einstein thinking experiments

Albert Einstein used to ponder these 5 mind-melting questions for fun. Can you figure them out?

• Albert Einstein was well known for his thought experiments involving complex scientific ideas.
• Often he used real-world examples that helped non-scientists grasp his theories of relativity.
• He started pondering one of them, about chasing a beam of light through space, when he was 16.

Albert Einstein , one of the greatest minds of the 20th century, forever changed the landscape of science by introducing revolutionary concepts that shook our understanding of the physical world.

One of Einstein's most defining qualities was his remarkable ability to conceptualize complex scientific ideas by imagining real-life scenarios. He called these scenarios Gedankenexperiments , which is German for thought experiments.

Despite the name, Einstein's mental exercises incorporated data from actual experiments.

Here are a few thought experiments that demonstrate some of Einstein's most groundbreaking discoveries, including his special and general theories of relativity .

What would happen if you chased a beam of light as it moved through space?

Einstein started wondering about this when he was just 16 years old. 

If you could somehow catch up to the light and travel as fast as it is going, Einstein reasoned, you would be able to observe the light frozen in space. But since he knew light was a wave composed of changing magnetic and electric fields, it couldn't truly be still.   

"One sees in this paradox the germ of the special relativity theory is already contained," Einstein wrote in his " Autobiographical Notes ." This "special" theory applies to certain relationships between space and time, and he further explored it with another thought experiment involving trains and light.

Can 2 people experience the exact same event differently? 

Imagine you're standing on a train while your friend is standing outside the train, watching it pass by. If lightning struck near both ends of the train, your friend would see both bolts flash at the same time.

But on the train, you are closer to the bolt of lightning you're moving toward. So you see this lightning first because the light has a shorter distance to travel.

The setup for this experiment is a bit complicated and involves angled mirrors and poles. But the result is that time behaves differently for someone moving than for someone standing still. 

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It cemented Einstein's belief that time and space are relative and simultaneity — two events happening at the same time — depends on your perspective. This is a cornerstone of Einstein's special theory of relativity.

How does your space-traveling twin age compared to you?

Let's say you have a twin who was born at almost the exact same time as you.

But almost immediately, your twin boards a spaceship and launches into space to travel through the universe at nearly the speed of light. 

Since, according to Einstein's special theory of relativity, time moves slower the closer you reach the speed of light, your twin in the spaceship would age more slowly.

When the spaceship landed back on Earth, you would be celebrating your 65th birthday, while your twin hadn't even turned 10 yet, based on an estimation from Omni Calculator.

Is your elevator accelerating or floating in space?

Imagine you are in a windowless elevator, unable to see what's happening outside. Without visual cues, you don't know if you're in a stationary elevator on Earth or in space being hauled upwards. Gravity's tug and upward acceleration in zero gravity both pull you to the floor.  

The physics of both events is the same, Einstein decided, based on the "principle of equivalence." Similarly, if your elevator were to plummet far and fast, you would float as though you were in space.

Now consider Einstein's previous assertion that time and space are relative. If motion can affect time and space (like with the train experiment) and gravity and acceleration behave the same, that means gravity can actually affect time and space. 

If you put a bowling ball on a trampoline, it will depress the fabric. Place marbles close by, and they will roll toward the ball. Objects with huge mass can affect space-time in a similar way. 

The ability of gravity to warp space-time is a key part of Einstein's general theory of relativity, which he published a decade after the special theory and expanded upon it.

Can particles communicate faster than the speed of light?

Einstein wasn't the biggest cheerleader for quantum theory. In fact, he argued back and forth with physicist Niels Bohr over certain occurrences that he believed violated fundamental laws of physics.

One of Einstein's thought experiments had to do with quantum entanglement, which he called " spooky action at a distance ."

Imagine you have a two-sided coin that you can easily split in half. You flip the coin. Without looking at the outcome, you hand one side to your friend and keep the other side for yourself. Then your friend gets on a rocket ship and travels across the universe.

When you look at your coin, you see you're holding the heads side of the coin. Instantly you know that your friend, who is billions of light years away, has the tails side.

Einstein's version of this thought experiment is more complicated than coins and involves entangled particles that share a wave function. Both particles have the potential to be in two possible states, spin up and spin down. Measuring one gives you information about the other, no matter how far apart they are.

It's a bit like if your half of the coin was neither heads nor tails until you looked at it. Since the coin wasn't double-sided, you know your friend has tails when you have heads. But Einstein thought particles behaved more like real coins. They had some inherent property that made them "spin up" or "spin down" all along.

Other scientists have proven him wrong in the decades since. In 2022, three physicists won the Nobel Prize for demonstrating spooky action at a distance.

Watch: Physicist breaks down the science behind 10 iconic Marvel scenes

• Main content

Einstein’s Relativity Explained in 4 Simple Steps

The revolutionary physicist used his imagination rather than fancy math to come up with his most famous and elegant equation.

Albert Einstein’s theory of relativity is famous for predicting some really weird but true phenomena, like astronauts aging slower than people on Earth and solid objects changing their shapes at high speeds.

But the thing is, if you pick up a copy of Einstein’s original paper on relativity from 1905, it’s a straightforward read. His text is plain and clear, and his equations are mostly just algebra—nothing that would bother a typical high-schooler.

That’s because fancy math was never the point for Einstein. He liked to think visually, coming up with experiments in his mind’s eye and working them around in his head until he could see the ideas and physical principles with crystalline clarity. (Read “ 10 Things You (Probably) Didn’t Know About Einstein. ”)

To bring his process to life, National Geographic created an interactive version of one of Einstein’s most famous thought experiments : a parable about lightning strikes as seen from a moving train that shows how two observers can understand space and time in very different ways.

Here’s how Einstein got started on his thought experiments when he was just 16, and how it eventually led him to the most revolutionary equation in modern physics.

1895: Running Beside a Light Beam

By this point, Einstein’s ill-disguised contempt for his native Germany’s rigid, authoritarian educational methods had already gotten him kicked out of the equivalent of high school, so he moved to Zurich in hopes of attending the Swiss Federal Institute of Technology (ETH). (Also see “ Why the FBI Kept a 1,400-Page File on Einstein .”)

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First, though, Einstein decided to put in a year of preparation at a school in the nearby town of Aarau—a place that stressed avant garde methods like independent thought and visualization of concepts. In that happy environment, he soon he found himself wondering what it would be like to run alongside a light beam.

Einstein had already learned in physics class what a light beam was: a set of oscillating electric and magnetic fields rippling along at 186,000 miles a second, the measured speed of light. If he were to run alongside it at just that speed, Einstein reasoned, he ought to be able to look over and see a set of oscillating electric and magnetic fields hanging right next to him, seemingly stationary in space.

Yet that was impossible. For starters, such stationary fields would violate Maxwell’s equations, the mathematical laws that codified everything physicists at the time knew about electricity, magnetism, and light. The laws were (and are) quite strict: Any ripples in the fields have to move at the speed of light and cannot stand still—no exceptions.

Worse, stationary fields wouldn’t jibe with the principle of relativity, a notion that physicists had embraced since the time of Galileo and Newton in the 17th century. Basically, relativity said that the laws of physics couldn’t depend on how fast you were moving; all you could measure was the velocity of one object relative to another.

But when Einstein applied this principle to his thought experiment, it produced a contradiction: Relativity dictated that anything he could see while running beside a light beam, including the stationary fields, should also be something Earthbound physicists could create in the lab. But nothing like that had ever been observed.

This problem would bug Einstein for another 10 years, all the way through his university work at ETH and his move to the Swiss capital city of Bern, where he became an examiner in the Swiss patent office. That’s where he resolved to crack the paradox once and for all.

1904: Measuring Light From a Moving Train

It wasn’t easy. Einstein tried every solution he could think of, and nothing worked. Almost out of desperation, he began to consider a notion that was simple but radical. Maybe Maxwell’s equations worked for everybody, he thought, but the speed of light was always constant.

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When you saw a light beam zip past, in other words, it wouldn’t matter whether its source was moving toward you, away from you, or off to the side, nor would it matter how fast the source was going. You would always measure that beam’s velocity to be 186,000 miles a second. Among other things, that meant Einstein would never see the stationary, oscillating fields, because he could never catch the light beam.

This was the only way Einstein could see to reconcile Maxwell’s equations with the principle of relativity. At first, though, this solution seemed to have its own fatal flaw. Einstein later explained the problem with another thought experiment: Imagine firing a light beam along a railroad embankment just as a train roars by in the same direction at, say, 2,000 miles a second.

Someone standing on the embankment would measure the light beam’s speed to be the standard number, 186,000 miles a second. But someone on the train would see it moving past at only 184,000 miles a second. If the speed of light was not constant, Maxwell’s equations would somehow have to look different inside the railway carriage, Einstein concluded, and the principle of relativity would be violated.

This apparent contradiction left Einstein spinning his wheels for almost a year. But then, on a beautiful morning in May 1905, he was walking to work with his best friend Michele Besso, an engineer he had known since their student days in Zurich. The two men were talking with about Einstein’s dilemma, as they often did. And suddenly, Einstein saw the solution. He worked on it overnight, and when they met the next morning, Einstein told Besso, “Thank you. I’ve completely solved the problem.”

May 1905: Lightning Strikes a Moving Train

Einstein’s revelation was that observers in relative motion experience time differently: it’s perfectly possible for two events to happen simultaneously from the perspective of one observer, yet happen at different times from the perspective of the other. And both observers would be right.

Einstein later illustrated this point with another thought experiment. Imagine that you once again have an observer standing on a railway embankment as a train goes roaring by. But this time, each end of the train is struck by a bolt of lightning just as the train’s midpoint is passing. Because the lightning strikes are the same distance from the observer, their light reaches his eye at the same instant. So he correctly says that they happened simultaneously.

Meanwhile, another observer on the train is sitting at its exact midpoint. From her perspective, the light from the two strikes also has to travel equal distances, and she will likewise measure the speed of light to be the same in either direction. But because the train is moving, the light coming from the lightning in the rear has to travel farther to catch up, so it reaches her a few instants later than the light coming from the front. Since the light pulses arrived at different times, she can only conclude the strikes were not simultaneous—that the one in front actually happened first.

In short, Einstein realized, simultaneity is what’s relative. Once you accept that, all the strange effects we now associate with relativity are a matter of simple algebra.

Einstein dashed off his ideas in a fever pitch and sent his paper in for publication just a few weeks later. He gave it a title—“ On the Electrodynamics of Moving Bodies ”—that spoke to his struggle to reconcile Maxwell’s equations with the principle of relativity. And he concluded it with a thank you to Besso (“I am indebted to him for several valuable suggestions”) that guaranteed his friend a touch of immortality.

September 1905: Mass and Energy

That first paper wasn’t the end of it, though. Einstein kept obsessing on relativity all through the summer of 1905, and in September he sent in a second paper as a kind of afterthought.

It was based on yet another thought experiment. Imagine an object that’s sitting at rest, he said. And now imagine that it spontaneously emits two identical pulses of light in opposite directions. The object will stay put, but because each pulse carries off a certain amount of energy, the object’s energy content will decrease.

Now, said Einstein, what would this process look like to a moving observer? From her perspective, the object would just keep moving in a straight line while the two pulses flew off. But even though the two pulses’ speed would still be the same—the speed of light—their energies would be different: The pulse moving forward along the direction of motion would now have a higher energy than the one moving backward.

With a little more algebra, Einstein showed that for all this to be consistent, the object not only had to lose energy when the light pulses departed, it had to lose a bit of mass, as well. Or, to put it another way, mass and energy are interchangeable.

Einstein wrote down an equation that relates the two. Using today’s notation, which abbreviates the speed of light using the letter c , he produced easily the most famous equation ever written: E = mc 2 .

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September 1, 2015

Lost in Thought—How Important to Physics Were Einstein’s Imaginings?

Einstein’s thought experiments left a long and somewhat mixed legacy of their own

By Sabine Hossenfelder

Gedankenexperiment , German for “thought experiment,” was Albert Einstein’s famous name for the imaginings that led to his greatest breakthroughs in physics. He traced his realization of light’s finite speed—the core idea of special relativity—to his teenage daydreams about riding beams of light. General relativity, his monumental theory of gravitation, has its origins in his musings about riding up and down in an elevator. In both cases, Einstein crafted new theories about the natural world by using his mind’s eye to push beyond the limitations of laboratory measurements.

Einstein was neither the first nor the last theorist to do this, but his remarkable achievements were pivotal in establishing the gedankenexperiment as a cornerstone of modern theoretical physics. Today physicists regularly use thought experiments to formulate new theories and to seek out inconsistencies or novel effects within existing ones.

But the modern embrace of thought experiments raises some uncomfortable questions. In the search for a grand unified theory that would wed the small-scale world of quantum mechanics with Einstein’s relativistic description of the universe at large, the most popular current ideas are bereft of observational support from actual experiments. Can thought alone sustain them? How far can we trust logical deduction? Where is the line between scientific intuition and fantasy? Einstein’s legacy offers no certain answers: On one hand, his reliance on the power of thought was a spectacular success. On the other, many of his best-known thought experiments were based on data from real experimentation, such as the classic Michelson-Morley experiment that first measured the constancy of the speed of light. Moreover, Einstein’s fixation on that which can be measured at times blinded him to deeper layers of reality—although even his mistakes in thought experiments contributed to later breakthroughs.

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Here we will walk through some of Einstein’s most iconic thought experiments, highlighting how they succeeded, where they failed and how they remain vital to questions now at the frontiers of theoretical physics.

The Windowless Elevator

In his thought experiments, Einstein’s genius was in realizing which aspects of experience were essential and which could be discarded. Consider his most famous one: the elevator thought experiment, which he began devising in 1907. Einstein argued that inside a windowless elevator, a person cannot tell whether the elevator is at rest in a gravitational field or is instead being hauled up with constant acceleration. He then conjectured that the laws of physics themselves must be identical in both situations. According to this “principle of equivalence,” locally (in the elevator), the effects of gravitation are the same as those of acceleration in the absence of gravity. Converted into mathematical equations, this principle became the basis for general relativity. In other words, the elevator thought experiment motivated Einstein to make the daring intellectual leap that ultimately led to his greatest achievement, his geometric description of gravity.

Credit: Nigel Holmes

Spooky Action

Later in his career, Einstein fought hard against the tenets of quantum mechanics, particularly the uncertainty principle, which dictates that the more you know about one aspect of a fundamental particle, such as its position, the less you can know about another, related aspect of that particle, such as its momentum—and vice versa. Einstein thought that the uncertainty principle was a sign that quantum theory was deeply flawed.

During a years-long exchange with Danish quantum theorist Niels Bohr, Einstein conceived of a series of thought experiments meant to demonstrate that it is possible to violate the uncertainty principle, but Bohr dissected every one of them. This exchange bolstered Bohr’s conviction that quantum uncertainty was a fundamental aspect of nature. If not even the great Einstein could devise a way to precisely measure both the position and the momentum of a particle, then certainly there must be something to the uncertainty principle!

In 1935, along with his colleagues Boris Podolsky and Nathan Rosen, Einstein published what was meant to be his most potent critique of the uncertainty principle. Perhaps because Podolsky, not Einstein, drafted the actual text of the paper, this Einstein-Podolsky-Rosen (EPR) thought experiment was presented not as an easy-to-imagine scenario of boxes, clocks and light beams but as an abstract series of equations describing interactions between two generalized quantum systems.

The simplest version of the EPR experiment studies the paradoxical behavior of “entangled” particles—pairs of particles that share a common quantum state. It unfolds as follows: Imagine an unstable particle with a spin of zero decaying into two daughter particles, which speed off in opposite directions. (Spin is a measure of a particle’s angular momentum, but counterintuitively, it has little to do with a particle’s rate of rotation.) Conservation laws dictate that the spins of those two daughter particles must add up to zero; one particle, then, could possess a spin value of “up,” and the other could have a spin value of “down.” The laws of quantum mechanics dictate that in the absence of measurement, neither of the particles possesses a definite spin until one of the two speeding entangled particles is measured. Once a measurement of one particle is made, the state of the other changes instantaneously , even if the particles are separated by vast distances!

Einstein believed this “spooky action at a distance” was nonsense. His own special theory of relativity held that nothing could travel faster than light, so there was no way for two particles to communicate with each other instantaneously from opposite sides of the universe. He suggested instead that the measurement outcomes must be determined prior to measurement by “hidden variables” that quantum mechanics failed to account for. Decades of discussion followed until 1964, when physicist John Stewart Bell developed a theorem quantifying exactly how the information shared between entangled particles differs from the information that Einstein postulated would be shared through hidden variables.

Since the 1970s lab experiments with entangled quantum systems have repeatedly confirmed that Einstein was wrong, that quantum particles indeed share mutual information that cannot be accounted for by hidden variables. Spooky action at a distance is real, but experiments have demonstrated that it cannot be used to transmit information faster than light, making it perfectly consistent with Einstein’s special relativity. This counterintuitive truth remains one of the most mysterious conundrums in all of physics, and it was Einstein’s stubborn, mistaken opposition that proved crucial to confirming it.

Alice and Bob

Today some of the most significant thought experiments in physics explore how to reconcile Einstein’s clockwork, relativistic universe with the fuzzy uncertainties inherent to quantum particles.

Consider, for instance, the widely discussed black hole information paradox. If you combine general relativity and quantum field theory, then you find that black holes evaporate, slowly radiating away their mass because of quantum effects. You also find that this process is not reversible: regardless of what formed the black hole, the evaporating black hole always produces the same featureless bath of radiation from which no information about its contents can be retrieved. But such a process is prohibited in quantum theory, which states that any occurrence can, in principle, be reversed in time. For instance, according to the laws of quantum mechanics, the leftovers of a burned book still contain all the information necessary to reassemble that book even though this information is not easily accessible. Not so for evaporating black holes. And so we arrive at a paradox, a logical inconsistency. A union of quantum mechanics and general relativity tells us that black holes must evaporate, but we conclude that the result is incompatible with quantum mechanics. We must be making some mistake—but where?

The thought experiments created to explore this paradox typically ask us to imagine a pair of observers, Bob and Alice, who share a pair of entangled particles—those spooky entities from the EPR experiment. Alice jumps into the black hole, carrying her particle with her, whereas Bob stays outside and far away with his. Without Alice, Bob’s particle is just typical, with a spin that might measure up or down—the information that it once shared with its entangled partner is lost, along with Alice.

Bob and Alice play a central role in one of the most popular proposed solutions to the paradox, called black hole complementarity. Proposed in 1993 by Leonard Susskind, Lárus Thorlacius and John Uglum, all then at Stanford University, black hole complementarity rests on Einstein’s golden rule for a gedankenexperiment: a strict focus on that which can be measured. Susskind and his colleagues postulated that the information falling in with Alice must come out later with the evaporating black hole’s radiation. This scenario would usually create another inconsistency because quantum mechanics allows only pair-wise entanglement with one partner at a time, a property called monogamy of entanglement. That is, if Bob’s particle is entangled with Alice’s, it cannot be entangled with anything else. But black hole complementarity requires that Bob’s particle be entangled with Alice’s and with the radiation the black hole later emits even though this violates monogamy. At first sight, then, black hole complementarity seems to exchange one inconsistency with another.

But like a perfect crime, if no one actually witnesses this inconsistency, perhaps it can subvert nature’s otherwise strict laws. Black hole complementarity relies on the argument that it is physically impossible for any observer to see Alice and Bob’s entangled particles breaking the rules.

To envision how this perfect quantum-mechanical crime could unfold, imagine a third observer, Charlie, hovering near the black hole, keeping an eye on Alice and Bob. He watches as Bob stays outside and as Alice falls in, measuring the black hole’s emitted radiation all the while. In theory, information encoded in that radiation could tip off Charlie that Bob and Alice had violated the monogamy of their entanglement. To know for certain, however, Charlie would have to compare his observations not only with Bob’s measurement but also with Alice’s— inside the black hole. So he must hover at the horizon, measure the emitted radiation, then jump in to tell Alice what he has found. Amazingly enough, Susskind and Thorlacius showed that no matter how hard Charlie tries, it is impossible for him to enter the black hole and compare his information with Alice’s before they are both torn apart by tidal forces. Their grisly fate suggests no violations of quantum mechanics can ever be measured by anybody around a black hole, and so theorists can commit this crime against nature with impunity.

Suffice it to say, not all theorists are convinced that this argument is valid. One criticism of black hole complementarity is that it might violate Einstein’s equivalence principle—the one that grew out of his elevator thought experiment. Einstein’s general relativity predicts that just as the elevator’s passenger cannot distinguish between gravity and acceleration, an observer crossing a black hole’s horizon should not notice anything unusual; there is no way an observer can tell that he or she has slipped past the point of no return.

Now let us return to the entanglement of Alice and Bob. If the radiation that Bob sees from far outside the hole contains all the information that we thought vanished with Alice behind the horizon, then this radiation must have been emitted with an extremely high energy; otherwise it would not have escaped the strong gravitational pull near the horizon. This energy is high enough to vaporize any infalling observer before he or she slips past the black hole’s horizon. In other words, black hole complementarity implies that black holes have a “firewall” just outside the horizon—and yet the firewall directly contradicts the predictions of Einstein’s equivalence principle.

At this point, we have ventured deep into the realm of theory. Indeed, we might never know the solutions to these puzzles. But because those solutions could lead to an understanding of the quantum nature of space and time, these puzzles are, for better or worse, some of the most vibrant areas of research in theoretical physics. And it all goes back to Einstein’s musings about falling elevators.

Sabine Hossenfelder is a physicist and research fellow at the Frankfurt Institute for Advanced Studies in Germany. She currently works on dark matter and the foundations of quantum mechanics.

Einstein Thought Experiments

Albert Einstein famously used thought experiments—experiments carried out in the mind only—to work out complex ideas. Here, watch animations of Einstein chasing a light beam (which helped lead him to his theory of special relativity) and riding an elevator in free-fall (which convinced him that gravity and acceleration are one and the same). Finally, see a visualization of one of the basic concepts of general relativity—that bodies like stars and planets warp the "fabric" of space-time.

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Gedankenexperiment

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• University of Pittsburgh - Chasing a Beam of Light: Einstein's Most Famous Thought Experiment
• The Encyclopedia of Science Fiction - Thought Experiment
• Stanford Encyclopedia of Philosophy - Thought Experiments
• Nature - Renninger’s Gedankenexperiment, the collapse of the wave function in a rigid quantum metamaterial and the reality of the quantum state vector

Gedankenexperiment , term used by German-born physicist Albert Einstein to describe his unique approach of using conceptual rather than actual experiments in creating the theory of relativity .

For example, Einstein described how at age 16 he watched himself in his mind’s eye as he rode on a light wave and gazed at another light wave moving parallel to his. According to classical physics , Einstein should have seen the second light wave moving at a relative speed of zero. However, Einstein knew that Scottish physicist James Clerk Maxwell ’s electromagnetic equations absolutely require that light always move at 3 × 10 8 metres (186,000 miles) per second in a vacuum . Nothing in the theory allows a light wave to have a speed of zero. Another problem arose as well: if a fixed observer sees light as having a speed of 3 × 10 8 metres per second, whereas an observer moving at the speed of light sees light as having a speed of zero, it would mean that the laws of electromagnetism depend on the observer. But in classical mechanics the same laws apply for all observers, and Einstein saw no reason why the electromagnetic laws should not be equally universal. The constancy of the speed of light and the universality of the laws of physics for all observers are cornerstones of special relativity .

Einstein used another Gedankenexperiment to begin building his theory of general relativity . He seized on an insight that came to him in 1907. As he explained in a lecture in 1922:

I was sitting on a chair in my patent office in Bern. Suddenly a thought struck me: If a man falls freely, he would not feel his weight. I was taken aback. This simple thought experiment made a deep impression on me. This led me to the theory of gravity.

Einstein was alluding to a curious fact known in English physicist Sir Isaac Newton ’s time: no matter what the mass of an object, it falls toward Earth with the same acceleration (ignoring air resistance) of 9.8 metres (32 feet) per second squared. Newton explained this by postulating two types of mass: inertial mass, which resists motion and enters into his general laws of motion , and gravitational mass, which enters into his equation for the force of gravity . He showed that, if the two masses were equal, then all objects would fall with that same gravitational acceleration.

Einstein, however, realized something more profound. A person standing in an elevator with a broken cable feels weightless as the enclosure falls freely toward Earth. The reason is that both he and the elevator accelerate downward at the same rate and so fall at exactly the same speed; hence, short of looking outside the elevator at his surroundings, he cannot determine that he is being pulled downward. In fact, there is no experiment he can do within a sealed falling elevator to determine that he is within a gravitational field. If he releases a ball from his hand, it will fall at the same rate, simply remaining where he releases it. And if he were to see the ball sink toward the floor, he could not tell if that was because he was at rest within a gravitational field that pulled the ball down or because a cable was yanking the elevator up so that its floor rose toward the ball.

Einstein expressed these ideas in his deceptively simple principle of equivalence, which is the basis of general relativity: on a local scale—meaning within a given system, without looking at other systems—it is impossible to distinguish between physical effects due to gravity and those due to acceleration.

In that case, continued Einstein’s Gedankenexperiment , light must be affected by gravity. Imagine that the elevator has a hole bored straight through two opposite walls. When the elevator is at rest, a beam of light entering one hole travels in a straight line parallel to the floor and exits through the other hole. But if the elevator is accelerated upward, by the time the ray reaches the second hole, the opening has moved and is no longer aligned with the ray. As the passenger sees the light miss the second hole, he concludes that the ray has followed a curved path (in fact, a parabola).

If a light ray is bent in an accelerated system, then, according to the principle of equivalence, light should also be bent by gravity, contradicting the everyday expectation that light will travel in a straight line (unless it passes from one medium to another). If its path is curved by gravity, that must mean that “straight line” has a different meaning near a massive gravitational body such as a star than it does in empty space. This was a hint that gravity should be treated as a geometric phenomenon.

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Thought Experiment: How Einstein Solved Difficult Problems

Thought experiments are a classic tool used by many great thinkers. They enable us to explore impossible situations and predict their implications and outcomes. Mastering thought experiments can help you confront difficult questions and anticipate (and prevent) problems .

The purpose of a thought experiment is to encourage speculation, logical thinking and to change paradigms. Thought experiments push us outside our comfort zone by forcing us to confront questions we cannot answer with ease. They demonstrate gaps in our knowledge and help us recognize the limits of what can be known.

“All truly wise thoughts have been thought already thousands of times; but to make them truly ours, we must think them over again honestly, until they take root in our personal experience.” Johann Wolfgang von Goethe

Famous thought experiments

Thought experiments have a rich and complex history, stretching back to the ancient Greeks and Romans.

An early example of a thought experiment is Zeno’s narrative of Achilles and the tortoise, dating to around 430 BC. Zeno’s thought experiments aimed to deduce first principles through the elimination of untrue concepts.

In one instance, the Greek philosopher used it to ‘prove’ motion is an illusion. Known as the dichotomy paradox, it involves Achilles racing a tortoise. Out of generosity, Achilles gives the tortoise a 100m head start. Once Achilles begins running, he soon catches up on the head start. However, by that point, the tortoise has moved another 10m. By the time he catches up again, the tortoise will have moved further. Zeno claimed Achilles could never win the race as the distance between the pair would constantly increase.

Descartes conducted a thought experiment, doubting the existence of everything he could until there was nothing left he could doubt.  Descartes could doubt everything except for the fact that he could doubt. His process left us with the philosophical thought experiment of ‘a brain in a vat’.

In the 17th century, Galileo used thought experiments to affirm his theories. One example is his thought experiment involving two balls (one heavy, one light) which are dropped from the Leaning Tower of Pisa. Prior philosophers had theorized the heavy ball would land first. Galileo claimed this was untrue, as mass does not influence acceleration.

According to Galileo’s early biography (written in 1654), he dropped two objects from the Leaning Tower of Pisa to disprove the gravitational mass relation hypothesis. Both landed at the same time, ushering in a new understanding of gravity. It is unknown if Galileo performed the experiment itself, so it is regarded as a thought experiment, not a physical one.

In 1814, Pierre Laplace explored determinism through ‘Laplace’s demon.’ This is a theoretical ‘demon’ which has an acute awareness of the location and movement of every single particle in existence. Would Laplace’s demon know the future? If the answer is yes, the universe must be linear and deterministic. If no, the universe is nonlinear and free will exists.

In 1897, the German term ‘Gedankenexperiment’ passed into English and a cohesive picture of how thought experiments are used worldwide began to form.

Albert Einstein used thought experiments for some of his most important discoveries. The most famous of his thought experiments was on a beam of light, which was made into a brilliant children’s book . What would happen if you could catch up to a beam of light as it moved he asked himself? The answers led him down a different path toward time, which led to the special theory of relativity.

Natural tendencies

In On Thought Experiments , 19th-century Philosopher and physicist Ernst Mach writes that curiosity is an inherent human quality. Babies test the world around them and learn the principle of cause and effect. With time, our exploration of the world becomes more and more in depth. We reach a point where we can no longer experiment through our hands alone. At that point, we move into the realm of thought experiments.

Thought experiments are a structured manifestation of our natural curiosity about the world.

Mach writes:

Our own ideas are more easily and readily at our disposal than physical facts. We experiment with thought, so as to say, at little expense. It shouldn’t surprise us that, oftentime, the thought experiment precedes the physical experiment and prepares the way for it… A thought experiment is also a necessary precondition for a physical experiment. Every inventor and every experimenter must have in his mind the detailed order before he actualizes it.

Mach compares thought experiments to the plans and images we form in our minds before commencing an endeavor. We all do this — rehearsing a conversation before having it, planning a piece of work before starting it, figuring out every detail of a meal before cooking it. Mach views this as an integral part of our ability to engage in complex tasks and to innovate creatively.

According to Mach, the results of some thought experiments can be so certain that it is unnecessary to physically perform it. Regardless of the accuracy of the result, the desired purpose has been achieved.

“It can be seen that the basic method of the thought experiment is just like that of a physical experiment, namely, the method of variation. By varying the circumstances (continuously, if possible) the range of validity of an idea (expectation) related to these circumstances is increased.” Ernst Mach

Thought experiments in philosophy

Thoughts experiments have been an integral part of philosophy since ancient times. This is in part due to philosophical hypotheses often being subjective and impossible to prove through empirical evidence.

Philosophers use thought experiments to convey theories in an accessible manner. With the aim of illustrating a particular concept (such as free will or mortality), philosophers explore imagined scenarios. The goal is not to uncover a ‘correct’ answer, but to spark new ideas.

An early example of a philosophical thought experiment is Plato’s Allegory of the Cave , which centers around a dialogue between Socrates and Glaucon (Plato’s brother.)

A group of people are born and live within a dark cave. Having spent their entire lives seeing nothing but shadows on the wall, they lack a conception of the world outside. Knowing nothing different, they do not even wish to leave the cave. At some point, they are led outside and see a world consisting of much more than shadows.

Plato used this thought experiment to illustrate the incomplete view of reality most of us have. Only by learning philosophy, Plato claimed, can we see more than shadows.

Upon leaving the cave, the people realize the outside world is far more interesting and fulfilling. If a solitary person left, they would want others to do the same. However, if they return to the cave, their old life will seem unsatisfactory. This discomfort would become misplaced, leading them to resent the outside world. Plato used this to convey his (almost compulsively) deep appreciation for the power of educating ourselves. To take up the mantle of your own education and begin seeking to understand the world is the first step on the way out of the cave.

Moving from caves to insects, here’s a thought experiment from 20th-century philosopher Ludwig Wittgenstein.

Imagine a world where each person has a beetle in a box. In this world, the only time anyone can see a beetle is when they look in their own box. As a consequence, the conception of a beetle each individual has is based on their own. It could be that everyone has something different, or that the boxes are empty, or even that the contents are amorphous.

Wittgenstein uses the ‘Beetle in a Box’ thought experiment to convey his work on the subjective nature of pain. We can each only know what pain is to us, and we cannot feel another person’s agony. If people in the hypothetical world were to have a discussion on the topic of beetles, each would only be able to share their individual perspective. The conversation would have little purpose because each person can only convey what they see as a beetle. In the same way, it is useless for us to describe our pain using analogies (‘it feels like a red hot poker is stabbing me in the back’) or scales (‘the pain is 7/10.’)

Thought experiments in science

Although empirical evidence is usually necessary for science, thought experiments may be used to develop a hypothesis or to prepare for experimentation. Some hypotheses cannot be tested (e.g, string theory) – at least, not given our current capabilities.Theoretical scientists may turn to thought experiments to develop a provisional answer, often informed by Occam’s razor .

In a paper entitled Thought Experimentation of Presocratic Philosophy , Nicholas Rescher writes:

In natural science, thought experiments are common. Think, for example, of Einstein’s pondering the question of what the world would look like if one were to travel along a ray of light. Think too of physicists’ assumption of a frictionlessly rolling body or the economists’ assumption of a perfectly efficient market in the interests of establishing the laws of descent or the principles of exchange, respectively.

In a paper entitled Thought Experiments in Scientific Reasoning , Andrew D. Irvine explains that thought experiments are a key part of science. They are in the same realm as physical experiments. Thought experiments require all assumptions to be supported by empirical evidence. The context must be believable, and it must provide useful answers to complex questions. A thought experiment must have the potential to be falsified .

Irvine writes:

Just as a physical experiment often has repercussions for its background theory in terms of confirmation, falsification or the like, so too will a thought experiment. Of course, the parallel is not exact; thought experiments…no do not include actual interventions within the physical environment.

In Do All Rational Folks Think As We Do? Barbara D. Massey writes:

Often critique of thought experiments demands the fleshing out or concretizing of descriptions so that what would happen in a given situation becomes less a matter of guesswork or pontification. In thought experiments we tend to elaborate descriptions with the latest scientific models in mind…The thought experiment seems to be a close relative of the scientist’s laboratory experiment with the vital difference that observations may be made from perspectives which are in reality impossible, for example, from the perspective of moving at the speed of light…The thought experiment seems to discover facts about how things work within the laboratory of the mind.

“We live not only in a world of thoughts, but also in a world of things. Words without experience are meaningless.” Vladimir Nabokov

Biologists use thought experiments, often of the counterfactual variety. In particular, evolutionary biologists question why organisms exist as they do today. For example, why are sheep not green? As surreal as the question is, it is a valid one. A green sheep would be better camouflaged from predators. Another thought experiment involves asking: why don’t organisms (aside from certain bacteria) have wheels? Again, the question is surreal but is still a serious one. We know from our vehicles that wheels are more efficient for moving at speed than legs, so why do they not naturally exist beyond the microscopic level?

Psychology and Ethics — The Trolley Problem

Picture the scene. You are a lone passerby in a street where a tram is running along a track. The driver has lost control of it. If the tram continues along its current path, the five passengers will die in the ensuing crash. You notice a switch which would allow the tram to move to a different track, where a man is standing. The collision would kill him but would save the five passengers. Do you press the switch?

The Trolley Problem was first suggested by philosopher Phillipa Foot, and further considered extensively by philosopher Judith Jarvis Thompson. Psychologists and ethicists have also discussed the trolley problem at length, often using it in research. It raises many questions, such as:

• Is a casual observer required to intervene?
• Is there a measurable value to human life? I.e. is one life less valuable than five?
• How would the situation differ if the observer were required to actively push a man onto the tracks rather than pressing the switch?
• What if the man being pushed were a ‘villain’? Or a loved one of the observer? How would this change the ethical implications?
• Can an observer make this choice without the consent of the people involved?

Research has shown most people are far more willing to press a switch than to push someone onto the tracks. This changes if the man is a ‘villain’- people are then far more willing to push him. Likewise, they are reluctant if the person being pushed is a loved one.

The trolley problem is theoretical, but it does have real world implications. As we move towards autonomous vehicles, there may be real life instances of similar situations. Vehicles may be required to make utilitarian choices – such as swerving into a ditch and killing the driver to avoid a group of children.

The Infinite Monkey Theorem and Mathematics

“Ford!” he said, “there’s an infinite number of monkeys outside who want to talk to us about this script for Hamlet they’ve worked out.” Douglas Adams, The Hitchhiker’s Guide to the Galaxy

In Fooled By Randomness , Nassim Taleb writes:

If one puts an infinite number of monkeys in front of (strongly built) typewriters, and lets them clap away, there is a certainty that one of them will come out with an exact version of the ‘Iliad.’ Upon examination, this may be less interesting a concept than it appears at first: Such probability is ridiculously low. But let us carry the reasoning one step beyond. Now that we have found that hero among monkeys, would any reader invest his life’s savings on a bet that the monkey would write the ‘Odyssey’ next?

The infinite monkey theorem is intended to illustrate the idea that any issue can be solved through enough random input, in the manner a drunk person arriving home will eventually manage to fit their key in the lock even if they do it without much finesse. It also represents the nature of probability and the idea that any scenario is workable, given enough time and resources.

To learn more about thought experiments, and other mental models, check out our book series, The Great Mental Models .

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Albert Einstein’s thought experiments For Beginners In Plain English

Jermaine Matthew

The German physicist Albert Einstein was well known for using visualized thought experiments, or Gedankenexperiments , to enrich his understanding and communicate physical concepts. His career was characterized by various types of thought experiments. A young man in his mind imagined himself chasing beams of light. A mental image of moving trains and a flash of lightning gave him profound insight into special relativity as he explored its intricacies. Among the scenarios he considered while working on general relativity were a person falling off a roof, elevators accelerating, and blind beetles crawling on curved surfaces. His debates with Niels Bohr about the nature of reality even included fictional devices that showed how he could potentially circumvent the uncertainty principle of Heisenberg. Furthermore, Einstein foreshadowed the concept of quantum entanglement in his inquiry into the interaction between two particles that briefly correlated their states before separating.

Introduction

An experiment involves logical reasoning and hypothetical scenarios used to explore a theory or concept. Scientists use imaginary or natural elements in idealized environments to explore the implications of theories or laws. With some idealization, these experiments describe scenarios that could be conducted…

Written by Jermaine Matthew

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The Simple Idea Behind Einstein’s Greatest Discoveries

The flashier fruits of Albert Einstein’s century-old insights are by now deeply embedded in the popular imagination: Black holes, time warps and wormholes show up regularly as plot points in movies, books, TV shows. At the same time, they fuel cutting-edge research, helping physicists pose questions about the nature of space, time, even information itself.

Quanta Magazine

Original story reprinted with permission from Quanta Magazine , an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research develop­ments and trends in mathe­matics and the physical and life sciences.

Perhaps ironically, though, what is arguably the most revolutionary part of Einstein’s legacy rarely gets attention. It has none of the splash of gravitational waves , the pull of black holes or even the charm of quarks. But lurking just behind the curtain of all these exotic phenomena is a deceptively simple idea that pulls the levers, shows how the pieces fit together, and lights the path ahead.

The idea is this: Some changes don’t change anything. The most fundamental aspects of nature stay the same even as they seemingly shape-shift in unexpected ways. Einstein’s 1905 papers on relativity led to the unmistakable conclusion, for example, that the relationship between energy and mass is invariant, even though energy and mass themselves can take vastly different forms. Solar energy arrives on Earth and becomes mass in the form of green leaves, creating food we can eat and use as fuel for thought. (“What is this mind of ours: what are these atoms with consciousness?” asked the late Richard Feynman . “Last week’s potatoes!”) That’s the meaning of E = mc 2 . The “ c ” stands for the speed of light, a very large number, so it doesn’t take much matter to produce an enormous amount of energy; in fact, the sun turns millions of tons of mass into energy each second.

This endless morphing of matter into energy (and vice versa) powers the cosmos, matter, life. Yet through it all, the energy-matter content of the universe never changes. It’s strange but true: Matter and energy themselves are less fundamental than the underlying relationships between them.

We tend to think of things, not relationships, as the heart of reality. But most often, the opposite is true. “It’s not the stuff,” said the Brown University physicist Stephon Alexander .

The same is true, Einstein showed, for “stuff” like space and time, seemingly stable, unchangeable aspects of nature; in truth, it’s the relationship between space and time that always stays the same, even as space contracts and time dilates. Like energy and matter, space and time are mutable manifestations of deeper, unshakable foundations: the things that never vary no matter what.

“Einstein’s deep view was that space and time are basically built up by relationships between things happening,” said the physicist Robbert Dijkgraaf , director of the Institute for Advanced Study in Princeton, New Jersey, where Einstein spent his final decades.

The relationship that eventually mattered most to Einstein’s legacy was symmetry. Scientists often describe symmetries as changes that don’t really change anything, differences that don’t make a difference, variations that leave deep relationships invariant. Examples are easy to find in everyday life. You can rotate a snowflake by 60 degrees and it will look the same. You can switch places on a teeter-totter and not upset the balance. More complicated symmetries have led physicists to the discovery of everything from neutrinos to quarks—they even led to Einstein’s own discovery that gravitation is the curvature of space-time, which, we now know, can curl in on itself, pinching off into black holes.

Over the past several decades, some physicists have begun to question whether focusing on symmetry is still as productive as it used to be. New particles predicted by theories based on symmetries haven’t appeared in experiments as hoped, and the Higgs boson that was detected was far too light to fit into any known symmetrical scheme. Symmetry hasn’t yet helped to explain why gravity is so weak, why the vacuum energy is so small, or why dark matter remains transparent.

“There has been, in particle physics, this prejudice that symmetry is at the root of our description of nature,” said the physicist Justin Khoury of the University of Pennsylvania. “That idea has been extremely powerful. But who knows? Maybe we really have to give up on these beautiful and cherished principles that have worked so well. So it’s a very interesting time right now.”

Einstein wasn’t thinking about invariance or symmetry when he wrote his first relativity papers in 1905, but historians speculate that his isolation from the physics community during his employment in the Swiss patent office might have helped him see past the unnecessary trappings people took for granted.

Like other physicists of his time, Einstein was pondering several seemingly unrelated puzzles. James Clerk Maxwell’s equations revealing the intimate connection between electric and magnetic fields looked very different in different frames of reference—whether an observer is moving or at rest. Moreover, the speed at which electromagnetic fields propagated through space almost precisely matched the speed of light repeatedly measured by experiments—a speed that didn’t change no matter what. An observer could be running toward the light or rushing away from it, and the speed didn’t vary.

Einstein connected the dots: The speed of light was a measurable manifestation of the symmetrical relationship between electric and magnetic fields—a more fundamental concept than space itself. Light didn’t need anything to travel through because it was itself electromagnetic fields in motion. The concept of “at rest” — the static “empty space” invented by Isaac Newton—was unnecessary and nonsensical. There was no universal “here” or “now”: Events could appear simultaneous to one observer but not another, and both perspectives would be correct.

Chasing after a light beam produced another curious effect, the subject of Einstein’s second relativity paper, “Does the Inertia of a Body Depend Upon Its Energy Content?” The answer was yes. The faster you chase, the harder it is to go faster. Resistance to change becomes infinite at the speed of light. Since that resistance is inertia, and inertia is a measure of mass, the energy of motion is transformed into mass. “There is no essential distinction between mass and energy,” Einstein wrote.

It took several years for Einstein to accept that space and time are inextricably interwoven threads of a single space-time fabric, impossible to disentangle. “He still wasn’t thinking in a fully unified space-time sort of way,” said David Kaiser , a physicist and historian of science at the Massachusetts Institute of Technology.

Unified space-time is a difficult concept to wrap our minds around. But it begins to make sense if we think about the true meaning of “speed.” The speed of light, like any speed, is a relationship—distance traveled over time. But the speed of light is special because it can’t change; your laser beam won’t advance any faster just because it is shot from a speeding satellite. Measurements of distance and time must therefore change instead, depending on one’s state of motion, leading to effects known as “space contraction” and “time dilation.” The invariant is this: No matter how fast two people are traveling with respect to each other, they always measure the same “space-time interval.” Sitting at your desk, you hurtle through time, hardly at all through space. A cosmic ray flies over vast distances at nearly the speed of light but traverses almost no time, remaining ever young. The relationships are invariant no matter how you switch things around.

Einstein’s special theory of relativity, which came first, is “special” because it applies only to steady, unchanging motion through space-time—not accelerating motion like the movement of an object falling toward Earth. It bothered Einstein that his theory didn’t include gravity, and his struggle to incorporate it made symmetry central to his thinking. “By the time he gets full-on into general relativity, he’s much more invested in this notion of invariants and space-time intervals that should be the same for all observers,” Kaiser said.

Specifically, Einstein was puzzled by a difference that didn’t make a difference, a symmetry that didn’t make sense. It’s still astonishing to drop a wad of crumped paper and a set of heavy keys side by side to see that somehow, almost magically, they hit the ground simultaneously—as Galileo demonstrated (at least apocryphally) by dropping light and heavy balls off the tower in Pisa. If the force of gravity depends on mass, then the more massive an object is, the faster it should sensibly fall. Inexplicably, it does not.

The key insight came to Einstein in one of his famous thought experiments. He imagined a man falling off a building. The man would be floating as happily as an astronaut in space, until the ground got in his way. When Einstein realized that a person falling freely would feel weightless, he described the discovery as the happiest thought of his life. It took a while for him to pin down the mathematical details of general relativity, but the enigma of gravity was solved once he showed that gravity is the curvature of space-time itself, created by massive objects like the Earth. Nearby “falling” objects like Einstein’s imaginary man or Galileo’s balls simply follow the space-time path carved out for them.

When general relativity was first published, 10 years after the special version, a problem arose: It appeared that energy might not be conserved in strongly curved space-time. It was well-known that certain quantities in nature are always conserved: the amount of energy (including energy in the form of mass), the amount of electric charge, the amount of momentum. In a remarkable feat of mathematical alchemy, the German mathematician Emmy Noether proved that each of these conserved quantities is associated with a particular symmetry, a change that doesn’t change anything.

Noether showed that the symmetries of general relativity—its invariance under transformations between different reference frames—ensure that energy is always conserved. Einstein’s theory was saved. Noether and symmetry have both occupied center stage in physics ever since.

Post Einstein, the pull of symmetry only became more powerful. Paul Dirac, trying to make quantum mechanics compatible with the symmetry requirements of special relativity, found a minus sign in an equation suggesting that “antimatter” must exist to balance the books. It does. Soon after, Wolfgang Pauli, in an attempt to account for the energy that seemed to go missing during the disintegration of radioactive particles, speculated that perhaps the missing energy was carried away by some unknown, elusive particle. It was, and that particle is the neutrino.

Starting in the 1950s, invariances took on a life of their own, becoming ever more abstract, “leaping out,” as Kaiser put it, from the symmetries of space-time. These new symmetries, known as “gauge” invariances, became extremely productive, “furnishing the world,” Kaiser said, by requiring the existence of everything from W and Z bosons to gluons. “Because we think there’s a symmetry that’s so fundamental it has to be protected at all costs, we invent new stuff,” he said. Gauge symmetry “dictates what other ingredients you have to introduce.” It’s roughly the same kind of symmetry as the one that tells us that a triangle that’s invariant under 120-degree rotations must have three equal sides.

Gauge symmetries describe the internal structure of the system of particles that populates our world. They indicate all the ways physicists can shift, rotate, distort and generally mess with their equations without varying anything important. “The symmetry tells you how many ways you can flip things, change the way the forces work, and it doesn’t change anything,” Alexander said. The result is a peek at the hidden scaffolding that supports the basic ingredients of nature.

Video: David Kaplan explains how the search for hidden symmetries leads to discoveries like the Higgs boson.

The abstractness of gauge symmetries causes a certain unease in some quarters. “You don’t see the whole apparatus, you only see the outcome,” Dijkgraaf said. “I think with gauge symmetries there’s still a lot of confusion.”

To compound the problem, gauge symmetries produce a multitude of ways to describe a single physical system — a redundancy, as the physicist Mark Trodden of the University of Pennsylvania put it. This property of gauge theories, Trodden explained, renders calculations “fiendishly complicated.” Pages and pages of calculations lead to very simple answers. “And that makes you wonder: Why? Where does all that complexity in the middle come from? And one possible answer to that is this redundancy of description that gauge symmetries give you.”

Such internal complexity is the opposite of what symmetry normally offers: simplicity. With a tiling pattern that repeats itself, “you only need to look at one little bit and you can predict the rest of it,” Dijkgraaf said. You don’t need one law for the conservation of energy and another for matter where only one will do. The universe is symmetrical in that it’s homogeneous on large scales; it doesn’t have a left or right, up or down. “If that weren’t the case, cosmology would be a big mess,” Khoury said.

The biggest problem is that symmetry as it’s now understood seems to be failing to answer some of the biggest questions in physics. True, symmetry told physicists where to look for both the Higgs boson and gravitational waves —two momentous discoveries of the past decade. At the same time, symmetry-based reasoning predicted a slew of things that haven’t shown up in any experiments, including the “supersymmetric” particles that could have served as the cosmos’s missing dark matter and explained why gravity is so weak compared to electromagnetism and all the other forces.

In some cases, symmetries present in the underlying laws of nature appear to be broken in reality. For instance, when energy congeals into matter via the good old E = mc 2 , the result is equal amounts of matter and antimatter — a symmetry. But if the energy of the Big Bang created matter and antimatter in equal amounts, they should have annihilated each other, leaving not a trace of matter behind. Yet here we are.

The perfect symmetry that should have existed in the early hot moments of the universe somehow got destroyed as it cooled down, just as a perfectly symmetrical drop of water loses some of its symmetry when it freezes into ice. (A snowflake may look the same in six different orientations, but a melted snowflake looks the same in every direction.)

“Everyone’s interested in spontaneously broken symmetries,” Trodden said. “The law of nature obeys a symmetry, but the solution you’re interested in does not.”

But what broke the symmetry between matter and antimatter?

It would come as a surprise to no one if physics today turned out to be burdened with unnecessary scaffolding, much like the notion of “empty space” that misdirected people before Einstein. Today’s misdirection, some think, may even have to do with the obsession with symmetry itself, at least as it’s currently understood.

Many physicists have been exploring an idea closely related to symmetry called “duality.” Dualities are not new to physics. Wave-particle duality—the fact that the same quantum system is best described as either a wave or a particle, depending on the context—has been around since the beginning of quantum mechanics. But newfound dualities have revealed surprising relationships: For example, a three-dimensional world without gravity can be mathematically equivalent , or dual, to a four-dimensional world with gravity.

If descriptions of worlds with different numbers of spatial dimensions are equivalent, then “one dimension in some sense can be thought of as fungible,” Trodden said.

“These dualities include elements—the number of dimensions—we think about as invariant,” Dijkgraaf said, “but they are not.” The existence of two equivalent descriptions with all the attendant calculations raises “a very deep, almost philosophical point: Is there an invariant way to describe physical reality?”

No one is giving up on symmetry anytime soon, in part because it’s proved so powerful and also because relinquishing it means, to many physicists, giving up on “naturalness”—the idea that the universe has to be exactly the way it is for a reason, the furniture arranged so impeccably that you couldn’t imagine it any other way.

Clearly, some aspects of nature—like the orbits of the planets—are the result of history and accident, not symmetry. Biological evolution is a combination of known mechanisms and chance. Perhaps Max Born was right when he responded to Einstein’s persistent objection that “God does not play dice” by pointing out that “nature, as well as human affairs, seems to be subject to both necessity and accident.”

Certain aspects of physics will have to remain intact—causality for example. “Effects cannot precede causes,” Alexander said. Other things almost certainly will not.

One aspect that will surely not play a key role in the future is the speed of light, which grounded Einstein’s work. The smooth fabric of space-time Einstein wove a century ago inevitably gets ripped to shreds inside black holes and at the moment of the Big Bang. “The speed of light can’t remain constant if space-time is crumbling,” Alexander said. “If space-time is crumbling, what is invariant?”

Certain dualities suggest that space-time emerges from something more basic still, the strangest relationship of all: What Einstein called the “spooky” connections between entangled quantum particles. Many researchers believe these long-distance links stitch space-time together . As Kaiser put it, “The hope is that something like a continuum of space-time would emerge as a secondary effect of more fundamental relationships, including entanglement relationships.” In that case, he said, classical, continuous space-time would be an “illusion.”

The high bar for new ideas is that they cannot contradict consistently reliable theories like quantum mechanics and relativity—including the symmetries that support them.

Einstein once compared building a new theory to climbing a mountain. From a higher perspective, you can see the old theory still standing, but it’s altered, and you can see where it fits into the larger, more inclusive landscape. Instead of thinking, as Feynman suggested, with last week’s potatoes, future thinkers might ponder physics using the information encoded in quantum entanglements, which weave the space-time to grow potatoes in the first place.

Original story reprinted with permission from Quanta Magazine , an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

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Albert Einstein’s Unique Approach to Thinking

“I never came upon any of my discoveries through the process of rational thinking.” — Albert Einstein

In the arena of scientific achievement and the quest to discover genius, Albert Einstein stands alone. He remains a profoundly important figure who undertook extraordinary, groundbreaking work that not only shaped the pillars of modern physics but greatly influenced the philosophy of science.

Quite literally, Einstein changed the way we see and travel across the world and cosmos. He was responsible for the  world’s most famous equation  and for discovering the theory of relativity, considered to be mankind’s highest intellectual discovery.

Einstein went about his work in unique ways. From visualization to daydreaming and even a dash of musical inspiration, Einstein’s creative insights and philosophical vantage points help guide the work we tackle today.

The power of play

“A new idea comes suddenly and in a rather intuitive way. But intuition is nothing but the outcome of earlier intellectual experience.” — Albert Einstein

Einstein took breaks from his work to play the violin. Beethoven favored “long, vigorous walks” in which he carried a pencil and blank sheet music. Mahler, Satie, and Tchaikovsky all believed in the power of the regularly-scheduled mid-day walk.

For some, it’s walks and breaks in the day. For others, it’s applying time to deep interest in areas that are completely different from their professional work. From music to painting, the pursuit of creative endeavors has the ability to help us discover and connect what we know to what we aspire to know.  

He viewed taking music breaks as an important part of his creative process. In addition to music, he was a proponent of ‘combinatory play’ — taking seemingly unrelated things outside the realms of science (art, ideas, music, thoughts), and blending them together to come up with new ideas.  It’s how he came up with his most famous equation , E=mc2.

“Combinatory play seems to be the essential feature in productive thought,” Einstein  wrote in a letter  (italicized in part below) to Jacques S. Hadamard, who was studying the thought process of mathematicians.

“…Words or the language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The psychical entities which seem to serve as elements in thought are certain signs and more or less clear images which can be “voluntarily” reproduced and combined…but taken from a psychological viewpoint, this combinatory play seems to be the essential feature in productive thought — before there is any connection with logical construction in words or other kinds of signs which can be communicated to others.”  —Albert Einstein

Creativity can’t be taught, but it can be harnessed and embraced. Nothing stokes the fires of our creative wants more than the thought of instantaneous creative inspiration—the lightning bolt or apple falling from the sky. In reality, creativity blossoms when you feed it like a fire hungry for more logs. And, creativity reaches its maximum potential when it’s stoked in combination with knowledge, ideas, and skills you’ve acquired throughout life. It’s why filmmakers seek out inspiration in art museums and why composers find notes in the daily music of everyday life.

Ideas and interludes

As Maria Popova,  author of Brainpickings  writes, organic synthesis of ideas happens when we step back and examine the patterns. Don’t mistake these moments for the illustrious and oft-debated lightning bolt of inspiration, even though they can happen while we are walking, showering, or even meditating. Think of them as important moments that are part of a sequential creative process that happen while we work and play. Think of the work as peering through the lens of a microscope in a lab, and the creativity starts to percolate when you take a break from the lab, pick up an instrument, or go for a walk.

These interludes helped Einstein connect the dots of his experiments at opportune moments when he picked up the violin. “I fell in love with Albert because he played Mozart so beautifully on the violin,”  recalled his second wife, Elsa . “He also plays the piano. Music helps him when he is thinking about his theories. He goes to his study, comes back, strikes a few chords on the piano, jots something down, returns to his study.”

Beauty in the science

“This kind of mental play uses both unconscious and conscious thinking: scanning various stimuli and information, perceiving patterns and clear or hidden similarities between things or ideas, and playing with their interconnections, relationships, and links,”  notes researcher Victoria Stevens , who explored the neuroscience of creativity in  To Think Without Thinking .

Stevens notes that the link between problem solver and creative thinker is essential. “Combinatory play provides a fertile field for neuroaesthetic investigation into the direct link between play, imagination, creativity, and empathy,” she writes.

While this imaginative combinatory play was an essential part of Einstein’s productive thought, the same type of thinking and a playful nature are essential to all artistic creations.  

“Personally, I experience the greatest degree of pleasure in having contact with works of art,” Einstein said. “They furnish me with happy feelings of intensity that I cannot derive from other sources.”

Einstein’s work was greatly influenced by art, and influenced artists, in turn.

Salvador Dali’s surrealist work has roots in the tiniest scientific elements of Einstein’s work. Dali had great interest in quantum mechanics and nuclear physics, and these atomic particles are the foundation of his painting  The Persistence of Memory , thought by some to represent the flexing of time.

Daydreaming FTW

Einstein’s early  academic and learning struggles are often debated .

As a 15 year old, he dropped out of school.  Einstein left school  because his teachers didn’t approve of visual imagination for learning, skills which became fundamental to his way of thinking. “Imagination is more important than knowledge,” Einstein would say.

It’s no coincidence that around the same time, Einstein began to use thought experiments that would change the way he would think about his future experiments. His first, at age 16, saw him chasing after a light beam which would help launch his discovery of special relativity.

His innate ability to conceptualize complex scientific details became a hallmark of his research. His work on gravity was influenced by imagining riding a free-falling elevator. This flight of fancy eventually led him to understand that gravity and acceleration were essentially the same.  

Using these simple thought experiments, Einstein was able to understand that time and space are both shaped by matter—the basis for the theory of general relativity. It’s astonishing that this thought experiment changed everything we thought we knew about the universe. Newton’s ideas of the universe were one-dimensional, but Einstein proposed that our universe was four dimensions, where stars, planets, and celestial bodies formed a “fabric” that were dynamically influenced by the bending and curving of gravitational pull.

Only recently has mankind been equipped  to explore much of what his theory had proposed—supernovas, black holes, and the evolution of our solar system.

An enduring legacy

Nearly a century later, Einstein’s legacy remains strong as ever. His theories of gravity, space, and time continue to influence a new generation of scientists. As Einstein continued his work, he maintained a natural sense of understanding of the world and compassion and kindness about people around him.

It’s only fitting that he was very aware of the incredibly short time we have on this planet, while at the same time understanding that all the work he accomplished was directly related to those who came before him. It’s comforting to know that he realized his work would be instrumental for all those who had yet to arrive.

“How strange is the lot of us mortals! Each of us is here for a brief sojourn; for what purpose he knows not, though he sometimes thinks he senses it. But without deeper reflection one knows from daily life that one exists for other people…a hundred times every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving,”   Einstein said .

20 Things You Need to Know About Einstein

Everything you need to know about the smartest man of the 20th century

Thought Process

Yes, his great breakthroughs came from visual experiments performed in his head rather than the lab. They were called Gedankenexperiment -- thought experiments. At age 16, he tried to picture in his mind what it would be like to ride alongside a light beam. If you reached the speed of light, wouldn't the light waves seem stationery to you? But Maxwell's famous equations describing electromagnetic waves didn't allow that. He knew that math was the language nature uses to describe her wonders, so he could visualize how equations were reflected in realities. So for the next ten years he wrestled with this thought experiment until he came up with the special theory of relativity.

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Thought Experiments

Thought experiments are basically devices of the imagination. They are employed for various purposes such an entertainment, education, conceptual analysis, exploration, hypothesizing, theory selection, theory implementation, etc. Some applications are more controversial than others. Few would object to thought experiments that serve to illustrate complex states of affairs, or those that are used in educational contexts. The situation is different, however, with respect to the appropriation of imagined scenarios to investigate reality (very broadly conceived to include things like electrons, tables, rain, beliefs, morals, people, numbers, universes, and even divine beings). It is this use of thought experiments that attracts most of the attention inside and outside of philosophical discourse. Significant is the overlap here with many other central philosophical topics, such as the nature of the imagination, the importance of understanding in contrast to explanation, the role of intuition in human cognition, and the relationship between fiction and truth. Moreover, thought experiments are interdisciplinary in two important respects. Firstly, not only philosophers study them as a research topic, but also historians, cognitive scientists, psychologists, etc. Secondly, they are used in many disciplines, including biology, economics, history, mathematics, philosophy, and physics (although, interestingly, not with the same frequency in each).

Most often thought experiments are communicated in narrative form, frequently with diagrams. It is important to distinguish between the imagined scenarios that are featured in thought experiments, on the one hand, and the narratives that establish those scenarios in people’s mind, on the other. Once a scenario is imagined it may assume a life on its own, and this explains partly the creative power of a good thought experiment. Experimental results may obtain that actually run counter to the narrative that initiated the discussion of an imagined scenario. Besides, thought experiments should be distinguished from thinking about experiments, from merely imagining any experiments to be conducted outside the imagination, and from psychological experiments with thoughts, though there may be some overlap. They should also be distinguished from counterfactual reasoning in general, as they seem to require a palpable element, which explains the impression that something is experienced in a thought experiment (i.e., being seen, felt, heard, etc.; not literally, of course). In other words, though many call any counterfactual or hypothetical situation a thought experiment (see, e.g., Rescher 1991), this appears too encompassing.

It is a quite different matter as to whether there is a logical structure common to all of thought experiments. Based on such considerations of logical structure, a taxonomy has been proposed according to which all thought experiments fall into two classes: “Necessity Refuters” and “Possibility Refuters” (see Sorensen 1992, 132–160). Such proposals especially fuel the debate about identity conditions of thought experiments. What modifications to logical structure does a thought experiment tolerate before it ceases to exist and a new one is born? In other words, how much emphasis on propositional characteristics is appropriate in the analysis of thought experiments?

Looking at the development of the discussion about thought experiments over the past thirty years, it is fair to say that thought experiments were primarily an important topic in the philosophy of science and the philosophy of philosophy (“metaphilosophy”), before the scope widened up at a later point. There is a simple reason for that path. At the core of the discussion sits a relatively simple epistemological challenge that is presented in a particularly powerful manner by numerous thought experiments that the history of science has to offer. They suggest that we can learn about the real world by virtue of merely thinking about imagined scenarios. But how can we learn about reality (if we can at all), just by thinking? This is the central question. Are there really thought experiments that enable us to acquire new knowledge about nature without new empirical data? If so, where does the new information come from, assuming that it takes new information to learn anything new about the world by means of thought experiments? Finally, how can we distinguish good from bad instances of thought experiments? These questions seem urgent with respect to scientific thought experiments, because many “recognize them as an occasionally potent tool for increasing our understanding of nature” (Kuhn 1977, p. 241). “Historically their role is very close to the double one played by actual laboratory experiments and observations. First, thought experiments can disclose nature’s failure to conform to a previously held set of expectations. Second, they can suggest particular ways in which both expectation and theory must henceforth be revised” (Kuhn 1977, p. 261). Yet, questions surrounding the epistemological challenge that certain scientific thought experiments pose, are equally urgent with respect to thought experiments outside of the natural sciences. This is especially true with respect to philosophy itself. Philosophy offers numerous examples of thought experiments that play a role similar in importance to some scientific thought experiments. And this fact provokes in turn further inquiries into the relationship between the natural sciences and philosophy, especially with respect to phenomena that implicate both the natural sciences and philosophy, such as the mind and free will (see, e.g., Wilkes 1988; Young 2013).

If scientific practice has room for thought experiments, then the question arises as to why we would want philosophical methodology to be more discriminatory in this respect. One reason that is often offered is that results of scientific thought experiments may be subjected to further empirical testing. Obviously, this can’t be done for philosophical thought experiments. But, it seems difficult to accept a categorical separation of science and philosophy along these lines. The 17th century saw some of the most brilliant practitioners of thought experimentation in Galileo, Descartes, Newton, and Leibniz, all of whom pursued the project of “natural philosophy.” And in our own time, the creation of quantum mechanics and relativity are almost unthinkable without the crucial role played by thought experiments, most of which relate to important philosophical issues that arise from these scientific theories. Besides, much of ethics, philosophy of language, and philosophy of mind is based on the results of thought experiments in a way that seems very similar to scientific thought experiments (though some might contest this), including Searle’s Chinese room, Putnam’s twin earth, and Jackson’s Mary the colour scientist. Philosophy, even more than the sciences, would be severely impoverished without thought experiments. These observations partly explain why it has been argued that a more “unified” account of thought experiments is desirable (see Boniolo 1997; Cooper 2005, pp. 329–330; Gähde 2000). Of course, it is important not to downplay the significant differences between the sciences and philosophy. But an account of thought experiments seems more powerful if it can do justice to the fact that not only in the sciences we find many of them.

There have been several attempts to define “thought experiment” along the lines of traditional conceptual analysis (see, e.g., Picha 2011; McComb 2013), but likely it will be better to leave the term loosely characterized, so as not to prejudice the ongoing investigation. Of course, we need to have some idea as to what thought experiments are to guide a proper philosophical analysis (see Häggqvist 2009), but this does not mean that we need to begin with a technical definition, specifying necessary and sufficient conditions. In fact, many of the most important concepts we deal with remain rather loosely defined when philosophical inquiry begins, e.g., religion or democracy. Luckily, there are plenty of examples to refer to in order to circumscribe our subject matter well enough. As well as those already mentioned, there are Newton’s bucket, Heisenberg’s gamma-ray microscope, Einstein’s elevator, Leibniz’s mill, Parfit’s people who split like amoebas, and Thomson’s violinist. Everyone is probably familiar with some of these. Less familiar thought experiments include the mouse that breaks into the tabernacle of a medieval Roman Catholic Church building to feed on the consecrated wafers kept in there (see Fehige 2018). Roman Catholic Christians believe that a consecrated wafer is the “body of Christ”. The “substance” of the wafer, understood in terms of Aristotelian categories, is believed to be replaced. In its place is the “substance” of Christ’s body after consecration by a priest. Only the Aristotelian “accidents” of the wafer remain intact (smell, colour, texture, etc.). Does the mouse eat the “body of Christ” (if any human actually does)? If not, then the “body of Christ” seems to be less than an objective reality; if yes, the “body of Christ” must be able to do good in the absence of a believing human soul. Another example less known is “the dome” thought experiment, which is to prove indeterminism in Newtonian physics. Imagine a mass sitting on a radially symmetric surface in a gravitational field. Guided by Newton’s laws of motion one comes to realize that the mass can either remain at rest for all times, or spontaneously move in an arbitrary direction (see Norton 2008). This thought experiment triggers a number of very interesting questions concerning the nature of Newtonian theory, the meaning of “physical”, and the role of idealizations in physics. And, of course, does it show what it claims? (see Malament 2008).

This entry continues with an overview of the characteristics of thought experiments in light of examples in Section 1. Section 2 reviews several taxonomies for classfying thought experiments and Section 3 sketches a history of philosophical inquiry into the nature of thought experiments. Section 4 covers several views representing the current state of the debate. The entry concludes by highlighting some trends in discussions surrounding the so-called laboratory of the mind.

1. Important Characteristics of Thought Experiments

2. taxonomies of thought experiments, 3. the history of thought experiments, 4.1 the skeptical objection, 4.2 the intuition–based account, 4.3 the argument view, 4.4 conceptual constructivism, 4.5 experimentalism, 4.6 the mental–model account, 5. going forward, other internet resources, related entries.

Theorizing about thought experiments usually turns on the details or the patterns of specific cases. Familiarity with a wide range of examples is crucial for commentators, and the list is very long (see, e.g., Stuart et al. 2018, pp. 558–560) We will provide a few here. One of the most beautiful early instances (found in Lucretius, De Rerum Natura 1.951–987; see Bailey 1950, pp. 58–59) attempts to show that space is infinite: if there is a purported boundary to the universe, we can toss a spear at it. If the spear flies through, it isn’t a boundary after all; if the spear bounces back, then there must be something beyond the supposed edge of space, a cosmic wall that stopped the spear, a wall that is itself in space. Either way, there is no edge of the universe; thus, space must be infinite.

This example nicely illustrates many of the most common features of what it means to engage in the conduct of thought experiments: we visualize some situation that we have set up in the imagination; we let it run or we carry out an operation; we see what happens; finally, we draw a conclusion. The example also illustrates the fallibility of thought experiments. Since the time of Lucretius, we’ve learned how to conceptualize space so that it could be both finite and unbounded. Imagine a circle, which is a one-dimensional space. As we move around, there is no edge, but it is nevertheless finite. The universe might be a three-dimensional version of this topology. It is, therefore, true that we must try to be mindful of unexpected limitations due to “physical scale effects” (Klee 2008), or other such things, when imagining counterfactual scenarios.

Figure 1. “Welcome to the edge of the Universe”

Often a real experiment that is meant to be the analogue of a thought experiment is impossible to be carried out as such due to physical, technological, ethical, or financial limitations (see, e.g., Sorensen 1992, pp. 200–202); but physical unrealizability needn’t be a defining condition of thought experiments. Rather, the main point is that we seem able to get a grip on nature just by thinking, and therein lies the great interest for philosophy. That was the position of Ernst Mach (see Mach, 1897 and 1905; for a most instructive assessments of his views see Kühne 2006, pp. 165–202, and Sorensen 1992, pp. 51–75). Thought experiments are on a spectrum of different kinds of experiments. They allow us to tap into a great store of “instinctive knowledge” picked up from past experience. We will get back to Mach’s theory further down. His account of thought experiments remains one of the major theories of how thought experiments work. One of Mach’s favourite examples is due to Simon Stevin (see Mach, 1883, pp. 48–58). When a chain is draped over a double frictionless plane, as in Fig. 2a, how will it move? Add some links as in Fig. 2b. Now it is obvious. The initial setup must have been in static equilibrium. Otherwise, we would have a perpetual motion machine; and according to our experience-based “instinctive knowledge,” says Mach, this is impossible. We do not have to perform the experiment in the real world, which we could not do, anyway, since it would require a perfectly frictionless plane. Nevertheless the outcome seems compelling.

Figure 2. “How will it move?”

Judith Thomson provided one of the most striking and effective thought experiments in the moral realm (see Thomson 1971). Her example is aimed at a popular anti-abortion argument that goes something like this: A fetus is an innocent person. All innocent persons have a right to life. Abortion results in the death of a fetus. Therefore, abortion is morally wrong. In her thought experiment, Thomson asks you to imagine a famous violinist falling into a coma. The society of music lovers determines from medical records that you and you alone can save the violinist’s life by being hooked up to him for nine months. The music lovers break into your home while you are asleep and hook the unconscious (and unknowing, hence innocent) violinist to you. You may want to unhook him, but you are then faced with the following argument put forward by the music lovers: The violinist is an innocent person. All innocent persons have a right to life. Unhooking him will result in his death. Therefore, unhooking him is morally wrong. However, the argument, even though it has the same structure as the anti-abortion argument, does not seem convincing in this case. You would be very generous to remain attached for nine months, but you are not morally obligated to do so. The parallel with the abortion case is evident. Thomson’s thought experiment is effective in distinguishing two concepts that had previously been run together: “right to life” and “right to what is needed to sustain life.” The fetus and the violinist might each have the former, but it is not evident that either has the latter. The upshot is that even if the fetus has a right to life (which Thomson does not believe but allows for the sake of the argument), it may still be morally permissible to abort. Those opposed to Thomson’s view have two options. They can either dismiss her thought experiment as a useless fiction. In fact, thought experiments as a method in ethics have their critics (see, e.g., Dancy 1985). Alternatively, they can provide a different version of the same scenario to challenge the conclusion. It is a very intriguing feature of thought experiments that they can be “rethought” (see Bokulich 2001). Real experiments are frequently open to reinterpretation, too. In this respect there does not seem to be a principled difference between the two classes of experiments.

Like arguments, thought experiments can be criticized in different ways. Perhaps the set up is faulty; perhaps the conclusions drawn from the thought experiment are not justified. Similar criticisms can arise in real experiments. Counter thought experiments are perhaps another form of criticism. They do not target the premises or conclusions involved in a particular thought experiment but question the phenomenon, i.e. the non-propositional heart of an imagined scenario (see Brown 2007). For example, Daniel Dennett is convinced that Frank Jackson’s Mary thought experiment is poor evidence to oppose physicalism in philosophy of mind. In Jackson’s version, Mary, who knows everything physics and the neurosciences can possibly know about colours but grew up in a colourless environment (seeing only black, white and grey things), allegedly learns something new when she sees a red tomato for the first time. Now she knows what it is like to experience red. This is an argument for qualia as something over and above the physical. Instead of a red tomato, Dennett, in his version of the thought experiment, presents Mary with a bright blue banana. In his version of the story (which seems just as plausible as Jackson’s), Mary balks and says she is being tricked, since she knows that bananas are yellow, and this, says Mary, is a consequence of knowing everything physical about colour perception. Mary does not learn anything new when she sees coloured objects for the first time, so there is no case against physicalism after all. Jackson’s initial thought experiment was very persuasive, but Dennett’s seems equally so, thus, undermining Jackson’s argument, although there is greater resistence to the conclusion of the latter than the former! Dennett complains a great deal about the ongoing “Mariology”, as he calls the continuing acceptance of Jackson’s thought experiment as a poweful case against physicalism.

Clearly, thought experiments are characterized by an intriguing plasticity, and this raises the interesting question of what it is that preserves the identity of a thought experiment. Replacing a red tomato with a blue banana might still leave us with the same thought experiment––slightly revised. But, at what point do we get a new thought experiment? This is not merely a question about conceptual vagueness. It helps to facilitate a discussion of the intuitively most plausible view about the cognitive efficacy of thought experiments, according to which this power depends on their being arguments, in a fairly strict sense of argument. John D. Norton holds such a view, which will be discussed below. In light of cases where the discussion of one and the same thought experiment played an important role in settling a dispute, the following problem arises: how can one and the same thought experiment support opposing views about a particular matter if the arguments that correspond to the different versions of the thought experiment that were entertained by the disputing parties are significantly different? The dilemma is: we could say that if there is more than one argument then there is more than one thought experiment involved in the dispute. But if that is true then the disputing parties simply talked past each other. One party presented an argument that the other party ignored while presenting their own. Alternatively, we can say that one thought experiment can correspond to many different arguments. But, if that is true then it becomes unclear in what non-trivial sense thought experiments are supposed to be identical with arguments (see Bishop 1999, and the response by Norton 2004, 63–64).

The plasticity of thought experiments coheres with another feature of thought experiments, namely that they seem to have “evidential significance only historically and locally, i.e., when and where premises that attribute evidential significance to it […] are endorsed” (McAllister 1996, p. 248).

Many taxonomies can be found in the literature. They are not mutually exclusive. We will present three of them. The first follows the type of purpose thought experiments serve. A very rudimentary version of it can be found in Mach (1897 and 1905). Such a classification makes sense, because an “imaginary experiment should be judged on its specific purpose” (Krimsky 1973, p. 331). Thought experiments are conducted for diverse reasons (see, e.g., DeMay 2006; Sorensen 1992, pp. 7–15), and this in a variety of areas, including economics (see, e.g., Herfeld 2019; Thoma 2016), education (Helm and Gilbert 1985; Helm et al. 1985, Klassen 2006; Sriraman 2006; Stonier 1990), history (see, e.g., Maar 2014; Reiss 2009), literature (see, e.g., Davies 2007; Elgin 2004), mathematics (see, e.g. Brown 1991 [2011], pp. 90–97; Glas 1999), morality (see, e.g., Hauerwas 1996; Wilson 2016), as well as the natural sciences (see Krimsky 1973), the socio-political realm (see, e.g. Roberts 1993: Thaler 2016), and theology (see, e.g., Gregersen 2014; Fehige 2024). Thought experiments may be used to entertain. This is probably true of short stories or novels which some argue qualify as thought experiments if certain conditions apply (see, e.g., Davenport 1983). Some thought experiments fulfil a specific function within a theory (see Borsboom et al. 2002). Others are executed because it is impossible to run the experimental scenario in the real world (see, e.g., Sorensen 1992, pp. 200–202). Sometimes thought experiments help to illustrate and clarify very abstract states of affairs, thereby accelerating the process of understanding (see Behmel 2001). Again others serve as examples in conceptual analysis (see Cohnitz 2006). And, then there are those that matter in the process of theory discovery (Praem and Steglich–Peterson 2015). The thought experiments that have received most of the attention are taken to provide evidence for or against a theory, putting them on a par with real-world experiments (see, e.g., Gendler 2004). The different ways to use thought experiments, of course, do not exclude one another. Most obviously, for example, a thought experiment can both entertain and make a case against a theory.

A second taxonomy classifies thought experiments in terms of their logical structure (see Sorensen 1992, pp. 132–166). The idea is to divide all thought experiments into two types of “alethic refuters”: “Although there are a number of ways to classify thought experiments, a refutation format scores the most points when judged by familiarity, specificity, and simplicity. According to this scheme, thought experiments aim at overturning statements by disproving one of their modal consequences. Modalities are operators that are applied to propositions to yield new propositions. There are deontic modalities ( permissible, forbidden ), epistemic modalities ( know, believe ), and alethic modalities ( possible, necessary ). The alethic modalities are the best–known and more–basic modality. Hence, we won’t miss anything by concentrating on them” (Sorensen 1992, p. 135). One type of thought experiment “is designed to refute a statement by showing that something ruled out as impossible by that statement is really possible after all” (Sorensen 1992, p. 135). The most discussed examples in the metaphilosophical discussion on thought experiments is of such a type, namely the Gettier scenarios (see Grundmann & Horvarth 2014; Saint-Germier 2019). They are designed to refute the claim that all knowledge is justified, true belief. They serve as a “necessity refuter.” The other type collects examples of “possibility refuters”. They don’t affirm “the possibility of the thought experiment’s content”. Instead, they establish “copossibilities”. A wonderful example is the scenario of an omnipotent God who faces the task of creating a stone too heavy for that God to lift. It seems God cannot succeed. The notion of divine omnipotence causes some headache here.

A third taxonomy (see Brown 1991, chapter 2), which has not gone unchallenged (see Norton 1993b), is more limited than the first two insofar as it focuses largely on the class of those thought experiments that are taken to function in theory choice, which is the use of thought experiments that has been receiving most of the attention. According to this taxonomy, the main division is constructive vs. destructive and resembles Karl Popper’s distinction between apologetic and critical thought experiments. Popper actually distinguishes between three types of thought experiments: heuristic (to illustrate a theory), critical (against a theory) and apologetic (in favour of a theory) (see Popper 1959). His case in favour of a critical and against an apologetic use of thought experiments is very limited. He focuses exclusively on quantum physics and doesn’t really say much to address the primary epistemological challenge presented by the success of critical thought experiments.

Among destructive thought experiments , the following subtypes can be identified: the simplest of these is to draw out a contradiction in a theory, thereby refuting it. The first part of Galileo’s famous falling bodies example does this. It shows that in Aristotle’s account, a composite body (cannon ball and musket ball attached) would have to fall both faster and slower than the cannon ball alone. A second subtype is constituted by those thought experiments that aim to show that the theory in question is in conflict with other beliefs that we hold. Schrödinger’s well-known cat paradox, for instance, does not show that quantum theory (at least on some interpretations) is internally inconsistent (see Schrödinger 1935, p. 812; translation: Trimmer 1980, p. 328): “A cat is penned up in a steel chamber, along with the following diabolical device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of one hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The first atomic decay would have poisoned it. The q-function of the entire system would express this by having in it the living and the dead cat (pardon the expression) mixed or smeared out in equal parts.” This thought experiment shows that quantum theory (as interpreted by Bohr) is in conflict with some very powerful common sense beliefs we have about macro-sized objects such as cats––they cannot be both dead and alive in any sense whatsoever. The bizarreness of superpositions in the atomic world is worrisome enough, says Schrödinger, but when it implies that same bizarreness at an everyday level, it is intolerable. There is a third subtype of negative thought experiments, namely when, in effect, a central assumption or premise of the thought experiment itself is undermined. For example, as we have seen above, Thomson showed with her thought experiment that “right to life” and “right to what is needed to sustain life” had been run together. When distinguished, the argument against abortion is negatively affected.

A fourth sub-type of negative thought experiments are “counter thought experiments” (see Brown 2007). Norton very usefully introduces a related idea: “thought-experiment/anti-thought-experiment pairs” (see Norton 2004, pp. 45–49). Above, we have already encountered this subtype in our discussion of Lucretius’ spear-thought experiment, and with Dennett’s reply to Jackson’s much discussed Mary the colour scientist thought experiment. Here we would like to add one more example, namely Mach’s counter thought experiment against absolute space. In his Principia Mathematica , Newton offers a pair of thought experiments as evidence for absolute space. One is the bucket thought experiment with water climbing the wall (see Fig. 3), the other is about a pair of spheres joined by a cord that maintained its tension in otherwise empty space (see Fig. 4). The explanation for these phenomena, argues Newton, is absolute space: the bucket and the joined spheres are rotating with respect to space itself. In response, Mach modifies the scenario and argues, contra Newton, that the two spheres would move toward one another thanks to the tension in the cord, and if we rotated a very thick, massive ring around a stationary bucket, we would see the water climb the bucket wall. (For further discussion of Mach’s counter thought experiment to Newton’s see Kühne 2006, pp. 191–202). In short, the point of Mach’s counter thought experiments is to describe the phenomena of the thought experiments’ scenarios differently, that is, to declare that different things would happen. Mach’s counter thought experiment undermines our confidence in Newton’s thought experiments. Absolute space might be a plausible explanation of the phenomena in Newton’s thought experiments, but now, in light of Mach’s counter thought experiment, we’re not so sure of the phenomena itself and thus of the idea of absolute space.

Figure 3. Stages in the bucket experiment

Figure 4. Two spheres held by a cord in otherwise empty space

To be effective, counter thought experiments needn’t be very plausible at all. In a court of law a jury would convict provided guilt is established “beyond a reasonable doubt.” A common defence strategy is to provide an alternative account of the evidence that has just enough plausibility to put the prosecution’s case into some measure of doubt. That is sufficient to undermine it. A counter thought experiment need only do that much to be effective, and in this sense it operates like a “necessity refuter” in Sorensen’s sense.

In addition to destructive ones, there is a second type, the constructive thought experiments . Unsurprisingly, there are many ways they could provide positive support for a theory. One of these is to provide a kind of illustration that makes a theory’s claims clear and evident. In such cases thought experiments serve as a kind of heuristic aid. A result may already be well established, but the thought experiment can lead to a very satisfying sense of understanding. In his Principia Mathematica , Newton provides a wonderful example showing how the moon is kept in its orbit in just the same way as an object falls to the earth (see Ducheyne 2006, pp. 435–437). He illustrates this by means of a cannon shooting a cannon ball further and further (see Fig. 5). In the limit, the earth curves away as fast as the ball falls, with the eventual result being that the cannon ball will return to the spot where it was fired, and, if not impeded, will go around again and again. This is what the moon is doing. We could arrive at the same conclusion through calculation. But Newton’s thought experiment provides that elusive sense of understanding. It’s a wonderful example of the “aha effect” that is typical of many powerful thought experiments.

Figure 5. “The shot heard around the world”

Thomson’s violinist showed that abortion could be morally permissible even when the fetus has a right to life. Similarly, Einstein’s elevator showed that light will bend in a gravitational field, because according to the principle of equivalence, there is no difference between such a frame of reference and one that is accelerating in free space; the laws of physics are the same in all. Suppose then, an observer is inside an elevator sealed off from the outside so that the observer cannot tell whether he is in a gravitational field or accelerating. If it were accelerating, and if a light beam were to enter one side, then, due to the elevator’s motion, the beam would appear to drop or curve down as it crossed the elevator. Consequently, it would have to do the same thing if the elevator was in a gravitational field. Therefore, gravity ‘bends’ light.

Maxwell’s demon showed that entropy could be decreased: The second law of thermodynamics implies that heat won’t pass from a cold body to a hot one. In classical thermodynamics this law is quite strict; but in Maxwell’s kinetic theory of heat there is a probability, though extremely small, of such an event happening. Some thought this a reductio ad absurdum of Maxwell’s theory. To show how it is possible to violate the second law, Maxwell imagined a tiny creature who controls a door between two chambers. Fast molecules from the cold box are let into the hot box, and slow molecules from the hot are allowed into the cold. Thus, there will be an increase in the average speed in the hot box and a decrease in the average speed of molecules in the cold. Since, on Maxwell’s theory, heat is just the average speed of the molecules, there has been a flow of heat from a cold body to a hot one.

Parfit’s splitting persons shows that survival is a more important notion than identity when considering personhood (for a critical discussion see Gendler 2002a). We say they “show” such and such, but, “purport to show” might be better, since some of these thought experiments are quite contentious. What they have in common is that they aim to establish something positive. Unlike destructive thought experiments, they are not trying to demolish an existing theory, though they may do that in passing. To repeat an important point: in principle, given the fact that thought experiments can be rethought (see Bokulich 2001), and that the evidential significance is dependent on historical and local accomplishments (see McAllister 1996), it cannot be irrelevant to identify the intention of the thought experimenter, if one wants to determine the type of a thought experiment: “An imaginary experiment should be judged on its specific purpose” (Krimsky 1973, p. 331).

The practice of thought experiments is not an invention of modern science. That fact may be obscured by the dominance of scientific examples in the lively discussions about thouht experiments today. The Pre-Socratics “invented thought experimentation as a cognitive procedure and practiced it with great dedication and versatility” (Rescher 2005, p. 2). “There is no ancient Greek term corresponding to what we nowadays refer to as a thought experiment, and presumably ancient philosophers did not have our modern notion of a thought experiment. But there is no doubt that they did use thought experiments. In fact, they often employed them in ways similar to those of contemporary philosophers, that is, both for defending their own theories as well as for refuting the theories of their opponents ” (Ierodiakonou 2018, p. 31). (See also Becker 2018; Diamond 2002, pp. 229–232; Fuhrer 2009; Glas 1999; Ierodiakonou 2005; Ierodiakonou and Roux (eds.) 2011; Irvine 1991; Rescher 1991 and 2005, pp. 61–72). The situation is similar with respect to medieval natural philosophy, although there are further nuances to be considered (see King 1991). According to Edward Grant, during the late Middle Ages “the imagination became a formidable instrument in natural philosophy and theology in ways that would have astonished ancient Greek natural philosophers, especially Aristotle” (Grant 2007, p. 201). But this doesn’t mean that we have reason to think of Aristotle as an opponent of the conduct of thought experiments tout court . On the contrary, “Aristotle uses thought experiments for argumentative persuasion and in places where, due to the obscure nature of the subject matter or the counterintuitive nature of the thesis they are meant to support, insight cannot be readily communicated by appeal to observational facts” (Corcilius 2018, p. 73). With a few exceptions that involved problems of motion, “the scholastics” of the medieval period made no meaningful effort to transform their hypothetical conclusions into specific knowledge about the physical world. They did, however, assume that although these hypothetical conclusions were naturally impossible, God could produce them supernaturally if he wished. Special attention received also a class of medieval thought experiments that does not rely on counterfactuals but depends on theological assumptions to study matters non-theological, namely those thought experiments involving angels, whose existence were affirmed at that time (see Perler 2008). Angels are gone by now (see Clark 1992), but not thought experiments. While most thought experiments involving angels have Christianity as their context, there is evidence of the practice of thought experiments also in the context of Islam and Judaism (see McGinnis 2018; Fisch 2019). In fact, the case has been made “that Ibn Sina is the first philosopher in the Aristotelian tradition, and thus perhaps the first in Western philosophy overall, to try to identify the psychological processes that go into postulating a hypothetical scenario. Ibn Sina also exhibits an interest in accounting for why, and to what extent, such psychological acts are thought to carry weight in our study of nature” (Kukkonen 2014, p. 434).

Ernst Mach is commonly credited with introducing the word “thought experiment” ( Gadankenexperiment ) and thereby coining a term for philosophical discussion (recently done, for instance, by Krauthausen 2015, p. 15). “ This view is incorrect, however! […] it can be substantiated that it was used […] already in 1811” (Witt-Hansen 1976, p. 48; see also Buzzoni 2008, pp. 14–15; 61–65; Kühne 2005, pp. 92–224; Moue et al. 2006, p. 63). The conceptual history of “thought experiment” goes back at least to the Danish “Tankeexperiment,” as it was used by Hans-Christian Ørsted. We can go back even further and find in the work of the German philosopher-scientist Georg Lichtenberg (1742–1799) a tacit theory of “experiments with thoughts and ideas.” These experiments help to overcome habits of thought that can inhibit scientific progress, and make possible an enlightened philosophy (see Schildknecht 1990, pp. 21; 123–169; Schöne 1982). Lichtenberg’s “aphoristic experiments” (see Stern 1963, pp. 112–126) reflect “that Lichtenberg’s scientific preoccupations are the formal and thematic prolegomena to his work as a literary artist” (Stern 1963, p. 126). Lichtenberg’s reflections on thought experimentation resemble those of Popper and Thomas S. Kuhn, and it is plausible to think of him as one important figure of the very first period in the history of philosophical inquiry into thought experiments (see Fehige and Stuart 2014).

Accordingly, the modern history of the philosophical investigation into thought experiments can be divided into four stages: in the 18th and 19th century the awareness of the importance of thought experiments in philosophy and science emerges. In addition to Lichtenberg and Hans-Christian Ørsted, special mention should be made of Novalis (see Daiber 2001). The topic reemerges in a more systematic manner at the beginning of the 20th century with little relation to the attempts made at the first stage. The stakeholders of the second stage were Pierre Duhem, Mach, and Alexius Meinong (see Duhem 1913, pp. 304–311; Mach, 1883, pp. 48–58, 1897 and 1905; Meinong 1907). A third stage, probably due to the rediscovery of the importance of scientific practice for a proper understanding of science, followed in the first part of the second half of the 20th century. Again, the contributions of this stage bear little relation to the two previous stages. While the third period has seen a number of noteworthy contributions (Cole 1983; Dancy 1985; Dennett 1985; Fodor 1964; Helm and Gilbert 1985; Helm et al. 1985; Krimsky 1973; McMullin 1985; Myers 1986; Poser 1984; Prudovsky 1989; Rehder 1980a,b; Yourgrau 1962 and 1967), the protagonists of this period were Alexandre Koyré, Kuhn and Popper. The ongoing philosophical exploration of thought experiments began in the 1980s, and marks the fourth stage. Arguably, it has been the most prolific one of all four stages. With some very important sign-postings in place (Horowitz and Massey (eds.) 1991; Sorensen 1992; Wilkes 1988), the ongoing discussion took off in light of a debate between James Robert Brown and John D. Norton (see for a concise statement of each position Brown 2004 and Norton 2004), which many have found useful to establish a contrast with their own alternative accounts of thought experiments. These views “represent the extremes of platonic rationalism and classic empiricism, respectively” (Moue et al. 2006, p. 69). They will be described below.

4. Current Views on Thought Experiments

At this point it is important to recall the key epistemological challenge described in the introduction: how can we learn about the real world through merely thinking about imagined scenarios? This challenge sits at the center of the discussion about thought experiments even though we must note that not all of the work discussed below focuses on it directly. Still, this section describes six views that can be seen as responding in some way to this challenge: The Skeptical Objection, The Intuition-Based Account, The Argument View, Conceptual Constructivism, Experimentalism, and The Mental-Model Account.

Of course, particular thought experiments have been contested. But for the most part, the practice of thought experiments in the sciences has been cheerfully accepted. Pierre Duhem, the great historian of physics, is almost alone in what has been understood as an outright condemnation of scientific thought experiments (see Duhem 1913, pp. 304–311). A thought experiment is no substitute for a real experiment, he claimed, and should be forbidden in science, including science education. However, in view of the important role of actual thought experiments in the history of physics — from Galileo’s falling bodies, to Newton’s bucket, to Einstein’s elevator — it is unlikely that anyone will feel or should feel much sympathy for Duhem’s strictures. We hasten to add that Buzzoni (2018) questions the validity of this reading of Duhem, and argues that already Mach’s reception of Duhem’s views suggests a more nuanced reading of Duhem’s position.

Philosophers can be as critical as Duhem when it comes to thought experimenting in their own field (see Peijnenburg; Atkinson 2003; Thagard 2014; Wilson 2016). At least thought experiments in science, the skeptic claims, can be tested by physical experiment. However, this is clearly false, since frictionless planes and universes empty of all material bodies cannot be produced in any laboratory. True, the results of philosophical thought experiments cannot be even approximately tested. But, skeptics say little about why thought experiments enjoy such popularity in philosophy. We are inclined to say that skeptics underestimate the importance of thought experiments for the creative mind in any field. Also, one mustn’t forget that the cognitive power of real world experiments isn’t a self-evident matter either.

Few are outright skeptics, however. Many take a more ambiguous stance. Sören Häggqvist, for example, has developed a normative model for philosophical thought experiments (see Häggqvist 1996 and 2009). Surprisingly, none of the commonly accepted philosophical thought experiments satisfies his model. And the process of identifying successful thought experiments is only the first step in addressing the central epistemological challenge posed by thought experiments. It gets much messier once we begin to ask exactly how reliable “successful” thought experiments are. Granted, there is some justice in worrying about the reliability of philosophical thought experiments (see, e.g., Klee 2008). This might be true for ethics (see Dancy 1985, Jackson 1992; Wilson 2016), conceptual analysis (see Fodor 1964), and the philosophy of mind: “A popular strategy in philosophy is to construct a certain sort of thought experiment I call intuition pump. […] Intuition pumps are often abused, though seldom deliberately” (Dennett 1985, p. 12). The claim by Dennett and others is that thought experiments too often rest on prejudice and faulty common sense; they are inherently conservative, while real science will likely result in highly-counterintuitive outcomes. Dennett believes that thought experiments rest on naive “folk concepts,” which is why they can be so misguided. It is far from clear that this is a fair charge. Everything involved in Galileo’s thought experiment that produced the principle of relativity could be called “folk concepts.” If we are inside a ship and perform a number of experiments, such as walking about, tossing a ball, watching birds fly about, we could not tell whether we are at rest in port or sailing over a smooth sea. The upshot is that nature behaves the same either way; the laws of nature are the same in any inertial frame. This result is profound and is still with us in Einstein’s relativity, whether it is folk physics or not.

Frequently discussed is the skeptical challenge raised by Kathleen Wilkes. She expresses a deep suspicion of scenarios such as Derek Parfit’s people splitting like an amoeba (see Parfit 1987; Gendler 2002a). Wilkes wants philosophy “to use science fact rather than science fiction or fantasy” (Wilkes 1988, p. 1), and therefore to refrain from using thought experiments because they are “both problematic and positively misleading” (Wilkes 1988, p. 2). She claims that thought experiments about personal identity in particular often fail to provide the background conditions against which the experiment is set (see Wilkes 1988, p. 7). She thinks we would not know what to say if we encountered someone who split like an amoeba. She insists that a legitimate thought experiment must not violate the known laws of nature. We do agree with Wilkes that underdetermination can be a problem. But instead of dismissing thought experiments in philosophy we should consider it a crucial factor in assessing the quality of a thought experiment (see Rescher 2005, pp. 9–14). That is to say that the more detailed the imaginary scenario in the relevant aspects is, the better the thought experiment (see Brendel 2004, pp. 97–99; Häggqvist 1996, p. 28).

We also agree that the inferences drawn in thought experimenting are highly problematic if the hypothetical scenario “is inadequately described” (Wilkes 1988, p. 8). But Wilkes seems to think that the lack of description is unavoidable, which supposedly amounts to a reason against philosophical thought experiments on personal identity because persons are not natural kinds. This makes it impossible to fill in necessary information to make the thought experiment work given its unavoidable underdetermination. Wilkes thinks that “whenever we are examining the ranges of concepts that do not pick on natural kinds, the problem of deciding what is or what is not ‘relevant’ to the success of the thought experiment is yet more problematic than the same question as it arises in science; and, unlike the scientific problem, it may not even have an answer in principle” (Wilkes 1988, p. 15). She adds that scientific laws — especially those describing biological kinds like human beings — “are not disjoint and independent, detachable from one another […]. They are interrelated, to varying degrees of course” (Wilkes 1988, p. 29). This implies, for example, that “a full psychophysiological account of the processes of human perception must at some stage link up with part at least of linguistic ability; for we typically see things under a certain description, and that description may be a very sophisticated one” (Wilkes 1988, p. 29). These considerations have her rule out experiments that challenge the human monopoly of personhood. No thought experiment, claims Wilkes, is well conceived if it involves non-human animals or computers as persons. But also those thought experiments can be ruled out which involve the “fission or fusion of humans” because it is not theoretically possible. “The total impact of the sum of laws that group us together as human beings (a natural kind category) precludes our splitting into two […] or fusing with someone else” (Wilkes 1988, p. 36).

One can ascertain here all too well the inherent difficulties in thinking about personal identity and the limited benefit some thought experiments might have for what is deemed the proper metaphysics of personal identity. Nevertheless, good reasons have been given in favour of the use of thought experiments about personal identity (see Beck 2006; Kolak 1993; Hershenov 2008). We also feel that the problems about thought experiments on personal identity reveal more about the intricate nature of the subject than about the usefulness of philosophical thought experiments. And, disregarding other shortcomings in Wilkes’ skepticism (for further discussion of Wilkes’ views see Beck 1992; Brooks 1994; Focquaert 2003; Häggqvist 1996, pp. 27–34), her suggestion that thought experimental scenarios would have to satisfy current scientific knowledge about the relevant entities featured in a thought experiment is highly implausible. We learn a great deal about the world and our theories when we wonder, for instance, what would have happened after the big bang if the law of gravity had been an inverse cube law instead of an inverse square. Would stars have failed to form? Reasoning about such a scenario is perfectly coherent and very instructive, even though it violates a law of nature.

To some extent we should share Wilkes’s concern that thought experimenting seems to be constrained only by relevant logical impossibilities and what seems intuitively acceptable. This is indeed problematic because intuitions can be highly misleading and relevant logical impossibilities are fairly ungrounded if they cannot be supplemented by relevant theoretical impossibilities based on current science in order to avoid the jump into futile fantasy. But in order to dismiss thought experimenting as a useful philosophical tool one has to show that intuition cannot be a source of knowledge and that an epistemic tool should be useless because there is a serious chance it can fail. Timothy Williamson has argued that we should forget about intuition as a cushion in the philosophical armchair (see Williamson 2004a,b, 2008, pp. 179–207, and 2009; see also Schaffer 2017). The importance of intuitions in philosophy has been neglected in the past (see Williamson 2004b, p. 109–110), and for too long intuition didn’t receive the attention it deserves (see, e.g., DePaul and Ramsey (eds.) 1998). Besides the traditional divide between empiricists, rationalists and skeptics, it is not only a very non-uniform use of the word “intuition” that makes it difficult to assess the progress of the last years of philosophical inquiry about intuitions. The situation has been complicated by the contributions of experimental philosophers on intuitions who add different reasons to question their reliability (see for a careful critique of those reasons: Ludwig 2007; see also Ludwig 2018). Generally speaking, the reliability of intuitions has been challenged on two grounds. One stems from an evolutionary explanation of the capacity to intuit; another is due to experiments which supposedly show the cultural relativity or racial and gender sensitivity of intuitions (see, e.g., Buckwalter and Stich 2010): “…a substantial list of philosophical intuitions vary across demographic groups and…they are influenced by a number of prima facie irrelevant factors…Some writers…have urged that these findings justify a thoroughgoing skepticism about the use of intuitions as evidence in philosophy…But we think this conclusion is much too strong…” (Stich & Toba 2018, p. 379). After all, knowledge without intuitions (if only common sense assumptions) seems impossible.

The recent discussion of intuitions in epistemology has barely made an impact on philosophical reflections about thought experiments. As far as philosophical thought experiments are concerned, this is as it should be, according to Williamson. In this respect George Bealer can be cited in support of Williamson, because for Bealer the talk about philosophical thought experiments reveals a conceptual confusion. Philosophy, he claims, is about “rational intuitions” and thought experiments can be only about “physical intuitions” (see Bealer 1998, pp. 207–208, and 2002, p. 74). To many, this is an implausible claim based on a deeply problematic “phenomenology of intuitions” resulting in a strict separation of “rational intuitions” from “physical intuitions”, on such grounds as an alleged immutability of “rational intuitions”. There are good reasons to believe that thought experiments appeal to intuitions in order to give us new insights about different realms of investigation, including philosophy. This kind of positive connection is what Williamson has in mind when addressing the role of intuitions in philosophical thought experiments like the famous Gettier cases, which overnight found acceptance by the philosophical community in their aim to refute the view that knowledge is justified true belief. While Williamson expects “armchair methods to play legitimately a more dominant role in future philosophy” (Williamson 2009, p. 126), he thinks that “we should stop talking about intuition” (Williamson 2004b, p. 152). This does not impress proponents of what we call an intuition-based account of thought experiments, and probably for good reasons, given the problems in Williamson’s approach (see, e.g., Dohrn 2016; Ichikawa and Jarvis 2009; Schaffer 2017), and the strong empirical evidence in favour of the positive role that intuitions does play in human cognition (see Myers 2004).

What we term the “intuition–based account” of thought experiments comes in a naturalistic version (see Brendel 2004; Gendler 2007), and in a Platonic version (see Brown 1991a [2011]). We begin with a discussion of the latter. Brown holds that in a few special cases we do go well beyond the old empirical data to acquire a priori knowledge of nature (see also Koyré 1968). Galileo showed that all bodies fall at the same speed with a brilliant thought experiment that started by destroying the then reigning Aristotelian account. The latter holds that heavy bodies fall faster than light ones ( H > L ). But consider Figure 6, in which a heavy cannon ball ( H ) and light musket ball ( L ) are attached together to form a compound object ( H + L ); the latter must fall faster than the cannon ball alone. Yet the compound object must also fall slower, since the light part will act as a drag on the heavy part. Now we have a contradiction: H + L > H and H > H + L . That’s the end of Aristotle’s theory. But there is a bonus, since the right account is now obvious: they all fall at the same speed ( H = L = H + L ).

Figure 6. Galileo: “I don’t even have to look”

Brown claims this is a priori (though still fallible) knowledge of nature, since there are no new data involved, nor is the conclusion derived from old data. Moreover, is it some sort of logical truth (for a technical challenge of this claim see Urbaniak 2012). This account of thought experiments can be further developed by linking the a priori epistemology to accounts of laws of nature that hold that laws are relations among objectively existing abstract entities. It is thus a form of Platonism, not unlike Platonic accounts of mathematics such as that urged by Kurt Gödel.

The two most often repeated arguments against this sort of Platonism are: it does not identify criteria to distinguish good from bad thought experiments, and it violates the principle of ontological parsimony. These seem weak objections. Perhaps they find widespread acceptance because Platonism seems to be unfashionable these days (see Grundmann 2018), given the general popularity of various forms of naturalism. If intuitions really do the job in a thought experiment, the first objection is weak because neither rationalists nor empiricists have a theory about the reliability of intuitions. So the objection should be that intuitions probably just do not matter in human cognition. However, there are good reasons to question the truth of this claim (see Myers 2004). This is not to marginalize the problems that arise when admitting intuitions as a source of knowledge and justification, especially in philosophy (see Hitchcock 2012).

As for the second objection, the appeal to Occam’s razor is in general problematic when it is employed to rule out a theory. Whatever we eliminate by employing the principle of parsimony, we can easily reintroduce it by an inference to the best explanation (see Meixner 2000). And this is exactly what a Platonist contends his or her Platonism about thought experimenting to be, while conceding that the Platonic intuition appears miraculous. But are they really more miraculous than sense perception, which seems similar in many respects to Platonic intuition? One might want to say yes, because supposedly we have no clue at all how Platonic intuition works but we do have some idea about the nature of sense perception. We know that if an object is far away it appears smaller in vision, and under certain light conditions the same object can look quite different. However, is it really impossible to state similar rules to capture the nature of Platonic intuition? If you are drunk or lack attention you most probably will not be very successful in intuiting anything of philosophical value.

A review of the relevant psychological literature will reveal further criteria that could be employed to identify good and bad conditions for Platonic intuition while thought experimenting. Yet, proponents of the naturalistic version of the intuition–based account wonder how necessary Platonism is once this move is entertained in defence of the reliability of intuitions (see Miščević 2004). Elke Brendel defines intuitions as mental propositional attitudes accompanied with a strong feeling of certainty. In her view, we can tell two stories to make sense of their cognitive power and plasticity. One story relates to our biological constitution and evolutionary past. The other is about membership in specialized communities. Brendel’s account raises many questions, but it is difficult to resist its appeal. A universal set is appealing to anyone not trained in logic because most things we are familiar with can come in sets, such as books, tables, and philosophers. A set of all sets seems intuitively plausible. The intuition disappears once you worked yourself through the problems arising from the idea of a set of all sets. Brendel is quick to insist that such relativity of our intuitions doesn’t imply that they are cognitively useless. Without intuitions, we probably wouldn’t have knowledge, and thought experiments are sometimes the only way to access the intuitions that guide us in our cognitive lives (see Brendel 2004).

John D. Norton is the most influential advocate of what we call “the argument view” of thought experiments (see Norton 1991, 1993, 1996, 2004a,b, 2008). Even though the argument view seems to be a natural option for empiricists, it seems that most empiricists find Norton’s argument view too strong. For this reason, many participants in the debate about thought experiments place themselves between the extreme views of Norton and Brown, which function as useful foils for apparently more moderate outlooks. Perhaps (with tongue in cheek) they could agree with Bernard Shaw on the virtues of moderation, when Shaw said of the typical member of the middle class that he is moderately honest, moderately intelligent, and moderately faithful to his spouse. Norton claims that any thought experiment is really a (possibly disguised) argument; it starts with premises grounded in experience and follows deductive or inductive rules of inference in arriving at its conclusion. The picturesque features of any thought experiment which give it an experimental flavour might be psychologically helpful, but are strictly redundant. Thus, says Norton, we never go beyond the empirical premises in a way to which any empiricist would object.

There are three objections that might be offered against Norton. First, his notion of argument is too vague. However, this might not be the best objection: arguments can be deductive (which are perfectly clear) or inductive. If the latter are unclear, the fault is with induction, not with Norton’s argument view. Second, it is argued that Norton simply begs the question: every real world experiment can be rephrased as an argument, but nobody would say that real world experiences are dispensable. The account does not address the question: where do the premises come from? A thought experiment might be an essential step in making the Norton-style reconstruction. Third, a thought experiment that is presented in argument form loses its typical force. The soft-point in Brown’s Platonism is linked to the strength of Norton’s account because Norton claims that any other view implies a commitment to “asking the oracle.” “Imagine an oracle that claims mysterious powers but never delivers predictions that could not be learned by simple inferences from ordinary experience. We would not believe that the oracle had any mysterious powers. I propose the same verdict for thought experiments in science” (Norton 1996, pp. 1142–1143). Defenders of empiricist alternatives deny this dispensability thesis. Brendel (2018) offers a most comprehensive review of merits and perils of the argument view.

“Conceptual constructivism”, as we could call it, is among the empiricist alternatives to the argument view. The position has been taken up by Van Dyck (2003) to account especially for Heisenberg’s ɣ-ray microscope; but also by Gendler (1998) to makes sense of Galileo’s falling body thought experiment. Gendler’s proposal was advanced in more general terms by Camilleri (2014) in order to establish a firm middle ground between the views of Norton and Brown. Conceptual constructivism was first proposed by Thomas Kuhn (1964). He employs many of the concepts (but not the terminology) of his well-known Structure of Scientific Revolutions . On his view a well-conceived thought experiment can bring on a crisis or at least create an anomaly in the reigning theory and so contribute to paradigm change. Thought experiments can teach us something new about the world, even though we have no new empirical data, by helping us to re-conceptualize the world in a new way. Accordingly, some have entertained the option of conceptual constructivism in the form of a Neo-Kantian reading of Einstein’s famous clock in the box thought experiment. Such an approach is inspired by Michael Friedman’s proposal to conceive of scientific revolutions as times when a Kantian kind of natural philosophy plays a major role in guiding scientists from one paradigm to another. The work of Kuhn left us with a puzzle: if scientific rationality is absolutely dependent on a paradigm, and if during scientific revolutions one paradigm replaces another, not in degrees but absolutely, comparable to a “Gestalt” switch, then this transition from one paradigm to the next cannot be a matter of scientific rationality. Are scientific revolutions irrational periods in the history of science? Not necessarily; some kind of natural philosophy may guide the process. Friedman has a Kantian natural philosophy in mind; his proposal did not earn wide acceptance, but the problem remains (see Fisch 2017). Be that as it may, it is true that thought experiments are a valuable currency in times of scientific revolution. For example, Lennox (1991) has argued that the revolution brought about by Charles Darwin in 1859 was made possible by thought experiments (among other things, of course).

What we might term “experimentalism” encompasses a wide range of different approaches which all advance the view that thought experiments are a “limiting case” of ordinary experiments. Experimentalism was proposed first by Ernst Mach (1897 and 1905). He defines experimenting in terms of its basic method of variation and its capacity to destroy prejudices about nature. According to Mach, experimenting is innate to higher animals, including humans. The thought experiment just happens on a higher intellectual level but is basically still an experiment. At the centre of thought experimenting is a “Gedankenerfahrung”, an experience in thought. Such an experience is possible because thought experiments draw from “unwillkürliche Abbildungen von Tatsachen” (non-arbitrary images of facts) acquired in past experiences of the world. Some thought experiments are so convincing in their results that an execution seems unnecessary; others could be conducted in a real-world experiment, which is the most natural trajectory of a scientific thought experiment. In any case thought experiments can result in a revision of belief, thereby demonstrating their significance for scientific progress. Mach also appreciates the didactic value of thought experiments: they help us to realize what can be accomplished in thinking and what cannot.

In the spirit of Mach, Sorensen (1992) has offered an aspiring version of experimentalism that accounts for thought experiments in science and philosophy, and tackles many of the central issues of the topic. Sorensen claims that thought experiments are “a subset of unexecuted experiments” (1992, p. 213). By their logical nature they are paradoxes that aim to test modal consequences of propositions. The origin of our capacity of thought experimentation is explained in terms of Darwinian evolution (as in Genz 1999, pp. 25–29), though the explanation has been criticized to be only little more than a ‘just so story’ that fails, on a posteriori grounds, to epistemically underwrite that capacity (see Maffie 1997). Others are more optimistic (see Shepard 2008).

Experimentalism does not have to take a naturalistic turn as it does in Sorensen’s case. In a number of contributions Marco Buzzoni has defended a Neo-Kantian version of experimentalism (see Buzzoni 2004, 2007, 2008, 2011, 2011b, 2013, 2013b). Buzzoni (2008) argues for the dialectical unity of thought experiments and real-world experiments. Thought experiments and real-world experiments are claimed to be identical on the “technological-operational” level, and at least in science, one is impossible without the other: without thought experiments there wouldn’t be real-world experiments because we would not know how to put questions to nature; without real-world experiments there wouldn’t be answers to these questions or experience from which they could draw. Given the many scientific thought experiments that cannot be realized in the real-world, Buzzoni might be conflating thought experiments with imagined experiments to be carried out in the real-world (see Fehige 2012, 2013b; and Buzzoni 2013b).

Idealizations are common in both real experiments and thought experiments. So-called Aristotelian idealization might ignore, say, the colour of a falling object. Galilean idealizations ignore some physical aspects, such as air friction, to get at the underlying physics (McMullin 1985). So-called Platonic idelization goes beyond this and ignores what would be actually seen even in a Galilean idealization. For instance, a rapidly moving object in special relativity would not look contracted, but rather would look rotated (surprisingly, this phenomenon is not well known). This rotation is ignored as an irrelevant optical phenomenon to yield the correct thought experiment visualization, which is the well-known Lorentz contraction (Brown 2013).

The last of the many accounts that emerged in the discussion about thought experiments is what could be called the “mental–model account.” It attracts the most followers (see Andreas 2011; Bishop 1998; Cooper 2005; Gendler 2004; Palmieri 2003; Nersessian 1992, 1993, 2007; McMullin 1985; Miščević 1992, 2007, 2021). When we conduct a thought experiment, according to champions of this view, we manipulate a mental model instead of the physical realm: “The general claim is that in certain problem-solving tasks people reason by constructing a mental model of the situations, events, and processes that in dynamic cases can be manipulated through simulation” (Nersessian 2018, p. 319). Like physical models, mental models are non-propositional in nature. This means first of all “that the carefully crafted thought–experimental narrative focuses on the construction of a model of a kind of situation and manipulating that model through simulation affords epistemic access to certain features of current representations in a way that manipulating propositional representations using logical rules cannot” (Nersessian 2018, pp. 319–320). A narrative functions as a kind of user-manual for building the model, but it isn’t identical to a thought experiment. The biggest problem for the mental–model account is to explain how something non-propositional like a mental model can make an impact on the propositional realm, which happens when a thought experiment causes a revision in beliefs.

The mental–model approach is one of the most promising of all the accounts the literature on thought experiments has to offer, and this for several reasons. First, it does not seem to be much of a stretch to draw connections to the intuition–based account. In fact, intuitions maybe the missing link to connect the essentially non-propositional activities surrounding mental models, on the one hand, and the propositional aspects of thought experiments, on the other. After all, thought experiments involve propositional reasoning, and somehow the non-propositional and propositional aspects of thought experiments must be linked in any account of thought experiments. This is urgent insofar as thought experiments are credited with a meaningful role in theory discovery and theory choice. Second, the mental–model approach also allows for inclusion of important elements of experimentalism and the argument–view. Thought experiments are realized in the mind on mental models, and the method of variation is employed such that the results of the experiment may be subject to a careful reconstruction of propositional lines of reasoning to submit it for careful assessment and critique. Third, the mental–model approach enables us to bring an aspect into focus that has been widely neglected in the discussion so far: the bodily component of (thought) experiments. The exception is the work of the late David Gooding (1992, 1993, 1994, and 1999). Fourth, in critical engagement with such naturalistic proposals, those theories of the body may be put to work that the philosophical school of phenomenology has produced (see Fehige and Wiltsche 2013). To be welcomed, therefore, is the entry of phenomenology into the discussion on thought experiments (see Hopp 2014; Wiltsche 2018). Fifth, the mental–model account also relates naturally to the most intriguing discussions about the role of literary fiction in thought experiments.

Some have placed “literary fiction on the level of thought experiments” (Swirski 2007, p. 6). There are two readings of such a claim. According to the first, some literary fiction may be of cognitive power due to the fact that they are thought experiments. In other words, we shouldn’t outright reject the idea that literature can be of cognitive value. Dystopian novels such as Orwell’s 1984 and Huxley’s Brave New World are obvious examples. According to the second reading, the power of thought experiments is partially a function of the narrative that conveys it. The work of Novalis remains relevant for the exploration of this link between narrative development and thought experiment: experimental writing and experiments on imagined scenarios go hand in hand; words and thoughts coincide; mind and matter are entangled (see Daiber 2001). According to the mental–model approach, both readings have a valid point. Literary fiction and narratives of thought experiments can be powerful in establishing mental models in such a way that we can even learn new things about the world at times from the fictional elements of them. The common denominator is the work on mental models each may facilitate. It is in this context that an appreciation can grow for Catherine Elgin’s theory of exemplification to argue against the “valorization of truth in epistemology” (2004, p. 113). This is also the place to consider Andras Kertesz’s (2015) work on conceptual metaphor research in its relevance to the epistemological puzzle that thought experiments pose.

Finally, sixth, mention could be made of visual reasoning in mathematics, which often seems closely related to thought experiments. The standard view of mathematics is that the one and only source of evidence is a proof, and a proof is a derivation from axioms or first principles. Let’s overlook the problem of where the first principles come from. A simple example such as the following casts doubt on the standard view:

Theorem: 1 + 2 + 3 + … + n = n 2 /2 + n/2 Proof: See Figure 7.

Figure 7. Picture proof.

The proof works like this: Start at the top and work down, letting the little squares represent numbers, 1 + 2 + 3 + 4 + 5 . The total number of squares in the picture is equal to this sum. Notice also that the numbers of squares is equal to a large square with sides of length 5 that is cut in half along the diagonal, i.e., 5 2 /2 , plus the shaded bits that were cut off by the diagonal cut, i.e., 5/2 . It is plausible to claim that the diagram is a perfectly good proof of the theorem. One can “see” complete generality in the picture. Even though it only illustrates the theorem for n = 5 , somehow we can see that it works for every number, all infinitely many of them. The diagram does not implicitly suggest a “rigorous” verbal or symbolic proof. The regular proof of this theorem is by mathematical induction, but the diagram does not correspond to an inductive proof at all, since the key element in an inductive proof is the passage from n to n + 1 . The simple moral we could draw from the example is just this: We can in special cases correctly infer theorems from pictures, that is, from visualizable situations. There is an intuition and from this intuition we can grasp the truth of the theorem (see Brown 1999 [2008]).

Our assessment of the prospects of the mental–model account is very rough and speculative, though certainly not implausible. Of course, there are challenges to such a vision of a greater synthesis of the many different takes on thought experiments under the umbrella of the mental-model account. For example, some see additional support arising for the argument–view from computer simulations (see Beisbart 2012). Others find that “computational modeling is largely replacing thought experimenting, and the latter will play only a limited role in future practice of science, especially in the sciences of complex nonlinear, dynamical phenomena” (see Chandrasekharan et al. 2012, p. 239). But, there are also proposals such as that by Marcus Schulzke (2014) to think of video games philosophically as executable thought experiments. Whatever the merits of this particular proposal, future explorations of the relationship between computer simulations and thought experiments can build on outcomes of closer inquiries into it (see Behmel 2001, pp. 98–108; Di Paolo et al . 2000; El Skaf and Imbert 2013; Lenhard 2011; Stäudner 1998; Lenhard 2018). The work on the nature of the importance of scientific understanding (see, e.g., Stuart 2018) will inform that exploration as much as the fruits of continuing efforts to clarify the role of the imagination in thought experiments (see, e.g., Meynell 2014; Stuart 2017 and 2021).

We conclude with an interesting, but still relatively unexplored issue that concerns the relative importance of thought experiments in different disciplines. Physics and philosophy use them extensively. Chemistry, by contrast, seems to attract less attention in this respect. Why is this the case? Perhaps it is merely an historical accident that chemists never developed a culture of doing thought experiments. Perhaps it is tied to some deep feature of the discipline itself (see Snooks 2006). Economics and history use thought experiments, but apparently not anthropology. A good explanation would likely tell us a lot about the structure of these disciplines.

Related to this is the question of the difference, if any, between thought experiments in the sciences and those in philosophy. We have assumed throughout this entry that they are the same kind of thing. Not everyone sees them this way, so perhaps it should be considered an open question. On the one hand, philosophy and science seem to many to be different kinds of activities. That might suggest that thought experiments would differ in the two areas. On the other hand, there is a huge difference between thought experiments within a single field, e.g., Newton’s bucket attempts to establish absolute space while Schrödinger’s cat aims to show QM as then understood to be absurd. Is the difference between them less than the difference between either of them and Searle’s Chinese Room or Thomson’s violinist? The case one way or the other is not obvious. Of course, there are differences between constructive and destructive thought experiments, but this is true within any discipline. Perhaps for now the default attitude ought to be that there is no categorical difference between scientific and philosophical thought experiments. This should not be treated as a dogmatic principle, but rather a stimulus to look deeper for important subtle contrasts.

The number of papers, anthologies, and monographs has been growing immensely since the beginning of the 1990s. It might be useful to highlight that in existing literature, Kühne (2006) remains the most substantial historical study on the philosophical exploration of thought experiments. And Sorensen (1992) remains the most comprehensive philosophical study of thought experiments. More than other monographs both of these studies well exceed the author’s own systematic contribution to what is widely considered the primary epistemological challenge presented by thought experiments. Also, this bibliography does not include the many (we count about eight) popular books on thought experiments (like Wittgenstein’s Beetle and Other Classical Thought Experiments by Martin Cohen); nor do we list fiction that is related to the subject (like The End of Mr. Y by Scarlett Thomas, or God’s Debris by Scott Adams). Further, for undergraduate teaching purposes one might want to consider Doing Philosophy: An Introduction Through Thought Experiments (edited by Theodore Schick, Jr. and Lewis Vaughn, fifth edition, 2012, Boston: McGraw Hill Higher Education), and chapter 5 of Timothy Williamson’s short introduction to philosophical method (Oxford University Press, 2020). Moreover, a number of philosophical journals have dedicated part or all of an issue to the topic of thought experiments, including the Croatian Journal of Philosophy (19/VII, 2007), Deutsche Zeitschrift für Philosophie (1/59, 2011), Informal Logic (3/17, 1995), Philosophica (1/72, 2003), Perspectives on Science (2/22, 2014), Berichte zur Wissenschaftsgeschichte (1/38, 2015)), as well as TOPOI (4/38, 2019), HOPOS (1/11, 2021), and Epistemologia (12/2022). Furthermore, a companion to thought experiments exists now: The Routledge Companion to Thought Experiments was published in 2017. Each includes substantial state of the art reports. The bibliography that follows aims to list only publications that address thought experiments as such. Not included are the many specialized papers that discuss a particular thought experiment in its systematic contribution to the discussion of a particular issue (such as Putnam’s twin earth scenario to support semantic externalism). An exception is made, of course, when such work is cited. Unlike in previous versions of this entry, we no longer aim for comprehensiveness in the bibliography that follows.

• Aligica, Paul D., and Anthony J. Evans, 2009, “Thought Experiments, Counterfactuals and Comparative Analysis”, The Review of Austrian Economics , 22: 225–239.
• Andreas, Holger, 2011, “Zur Wissenschaftslogik von Gedankenexperimenten”, Deutsche Zeitschrift für Philosophie , 59: 75–91.
• Arthur, Richard, 1999, “On Thought Experiments as A Priori Science”, International Studies in the Philosophy of Science , 13: 215–229.
• Bailey, Cyril, 1950, Lucretius on the Nature of Things (translation of De Rerum Naturae ), ninth reprint, Oxford: Clarendon Press.
• Batens, Diderik, 2008, “On Possibilities and Thought Experiments”, in R. Almeder (ed.), Rescher Studies , Heusenstamm: Ontos Verlag, 29–57.
• Bealer, George, 1998, “Intuition and the Autonomy of Philosophy”, in M. DePaul and W. Ramsey (eds.), Rethinking Intuition: The Psychology of Intuition & Its Role in Philosophical Inquiry , Lanham: Rowman & Littlefield, 201–239.
• –––, 2002, “Modal Epistemology and the Rationalist Renaissance”, in T. S. Gendler and J. Hawthorne (eds.), Conceivability and Possibility , Oxford: Clarendon Press, 71–125.
• Beck, Simon, 1992, “Should we Tolerate People who Split?”, Southern Journal of Philosophy , 30: 1–17.
• –––, 2006, “These Bizarre Fictions: Thought Experiments, Our Psychology and Our Selves”, Philosophical Papers , 35: 29–54.
• Becker, Alexander, 2018, “Thought Experiments in Plato”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 44–56.
• Behmel, Albrecht, 2001, Was sind Gedankenexperimente? Kontrafaktische Annahmen in der Philosophie des Geistes – der Turingtest und das Chinesische Zimmer , Stuttgart: Ibidem.
• Beisbart, Claus, 2012, “How can Computer Simulations Produce New Knowledge?”, European Journal for Philosophy of Science , 2: 395–434.
• Belkin, Aron, and Tetlock, Philip E. (eds.), 1996, World Politics: Logical, Methodological, and Psychological Perspectives , Princeton: Princeton University Press.
• Bishop, Michael, 1998, “An Epistemological Role for Thought Experiments”, in N. Shanks (ed.), Idealization IX: Idealization in Contemporary Physics , Amsterdam/Atlanta, GA: Rodopoi, 19–33.
• –––, 1999, “Why Thought Experiments are Not Arguments”, Philosophy of Science , 66: 534–541.
• Bokulich, Alisa, 2001, “Rethinking Thought Experiments”, Perspectives on Science , 9: 285–307.
• Boniolo, Giovanni, 1997, “On a Unified Theory of Models and Thought Experiments in Natural sciences”, International Studies in Philosophy of Science , 11: 121–142.
• Borsboom, Denny, et al., 2002, “Functional Thought Experiments”, Synthese , 130: 379–387.
• Borstner, Bojan, and Gartner Smiljana (eds.), 2017, Thought Experiments between Nature and Society , Newcastle upon Tyne, UK: Cambridge Scholars Publishing.
• Brendel, Elke, 1999, “Gedankenexperimente als Motor der Wissenschaftsdynamik”, in J. Mittelstraß (ed.), Die Zukunft des Wissens. XVIII. Deutscher Kongress für Philosophie , Konstanz: UVK, 785–792.
• –––, 2004, “Intuition Pumps and the Proper Use of Thought Experiments”, Dialectica , 58: 88–108.
• –––, 2018, “The Argument View: Are Thought Experiments Mere Picturesque Arguments?”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 281–293.
• Brooks, David H. M., 1994, “The Method of Thought Experiment”, Metaphilosophy , 25: 71–83.
• Brown, James Robert, 1986, “Thought Experiments since the Scientific Revolution”, International Studies in the Philosophy of Science , 1: 1–15.
• –––, 1991 [2011], Laboratory of the Mind: Thought Experiments in the Natural Sciences , London: Routledge, Second Edition.
• –––, 1999 [2008], Philosophy of Mathematics: A Contemporary Introduction to the World of Proofs and Pictures , London and New York: Routledge, second edition.
• –––, 2004, “Why Thought Experiments Do Transcend Empiricism”, in C. Hitchcock (ed.), Contemporary Debates in the Philosophy of Science , Malden, MA: Blackwell, 23–43.
• –––, 2004b, “Peeking into Plato’s Heaven”, Philosophy of Science , 71: 1126–1138.
• –––, 2007, “Counter Thought Experiments”, Royal Institute of Philosophy Supplement 61 , 82: 155–177.
• –––, 2011, “Über das Leben im Labor des Geistes”, Deutsche Zeitschrift für Philosophie , 59: 65–73.
• –––, 2013, “What Do We See In a Thought Experiment?”in M. Frappier et al. (ed.), Thought Experiments in Science, Philosophy, and the Arts , New York and London: Routledge, 52–68.
• Bunzl, Martin, 1996, “The Logic of Thought Experiments”, Synthese , 106: 227–240.
• Buschlinger, Wolfgang, 1993, Denkkapriolen. Gedankenexperimente in Naturwissenschaften, Ethik und Philosophy of Mind , Würzburg: Königshausen & Neumann.
• Butkovic, Ana, 2007, “What is the Function of Thought Experiments: Kuhn vs. Brown”, Croatian Journal of Philosophy , VII: 63–67.
• Buzzoni, Marco, 2004, Esperimento Ed Esperimento Mentale , Milano: FrankoAngeli.
• –––, 2007, “Zum Verhältnis zwischen Experiment und Gedankenexperiment in den Naturwissenschaften”, Journal for General Philosophy of Science , 38: 219–237.
• –––, 2008, Thought Experiment in the Natural Sciences , Würzburg: Königshausen & Neumann.
• –––, 2011, “Kant und das Gedankenexperimentieren”, Deutsche Zeitschrift für Philosophie , 59: 93–107.
• –––, 2011b, “On Mathematical Thought Experiments”, Epistemologia: Italian Journal for Philosophy of Science , XXXIV: 61–88.
• –––, 2013, “Thought Experiments from a Kantian Point of View”, in M. Frappier et al. (ed.), Thought Experiments in Science, Philosophy, and the Arts , New York and London: Routledge, 90–106.
• –––, 2013b, “On Thought Experiments and the Kantian A Priori in the Natural Sciences: A Reply to Yiftach J. H. Fehige”, Epistemologia: Italian Journal for Philosophy of Science , XXXVI: 277–293.
• –––, 2015, “Causality, Teleology, and Thought Experiments in Biology”, Journal for General Philosophy of Science , 46: 279–299.
• –––, 2018, “Pierre Duhem and Ernst Mach on Thought Experiments”, HOPOS: The Journal of the International Society for the History of Philosophy of Science , 8: 1–27.
• Camilleri, Kristian, 2012, “Toward a Constructivist Epistemology of Thought Experiments in Science”, Synthese , 191: 1697–1716.
• Cargile, James, 1987, “Definitions and Counterexamples”, Philosophy , 62: 179–193.
• Chandrasekharan, Sanjay et al, 2013, “Computational Modeling: Is This the End of Thought Experiments in Science?”, in M. Frappier et al. (eds.), Thought Experiments in Philosophy, Science, and the Arts , London: Routledge, 239–260.
• Clark, Stephen R. L., 1992, “Where have all the Angels Gone?”, Religious Studies , 28: 221–234.
• Clatterbuck, Hayley, 2013, “The Epistemology of Thought Experiments: A Non-eliminativist, Non-platonic Account”, European Journal for Philosophy of Science , 3: 309–329.
• Cohnitz, Daniel, 2006, Gedankenexperimente in der Philosophie , Paderborn: mentis.
• Cole, David, 1984, “Thought and Thought Experiment”, Philosophical Studies , 45: 431–444.
• Cooper, Rachel, 2005, “Thought Experiments”, Metaphilosophy , 36: 328–347.
• Corcilius, Klaus, 2018, “Aristotle and Thought Experiments”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 57–76.
• Cowley, Robert (ed.), 1999, What-If? The World’s Most Foremost Military Historians Imagine What Might Have Been , New York: Putnam.
• ––– (ed.), 2001, More What-If?: Eminent Historians Imagine What Might Have Been , New York: Putnam.
• Crick, Nathan, 2004, “Conquering our Imagination: Thought Experiments and Enthymemes in Scientific Argument”, Philosophy and Rhetoric , 37: 21–41.
• Daiber, Jürgen, 2001, Experimentalphysik des Geistes: Novalis und das romantische Experiment , Göttingen: Vadenhoeck & Ruprecht.
• Dancy, Jonathan, 1985, “The Role of Imaginary Cases in Ethics”, Pacific Philosophical Quarterly , 66: 141–153.
• Davenport, Edward A., 1983, “Literature as Thought Experiment (On Aiding and Abetting the Muse)”, Philosophy of the Social Sciences , 13: 279–306.
• Davies, David, 2007, “Thought Experiments and Fictional Narratives”, Croatian Journal of Philosophy , VII: 29–45.
• De Baere, Benoit, 2003, “Thought Experiments, Rhetoric, and Possible Worlds”, Philosophica , 72: 105–130.
• De Mey, Tim, 2003, “The Dual Nature View of Thought Experiments”, Philosophica , 72: 61–78.
• –––, 2005a, “Remodeling the Past”, Foundations of Science , 10: 47–66.
• –––, 2005b, “Tales of the Unexpected: Incongruity-Resolution in Humour Comprehension, Scientific Discovery and Thought Experimentation”, Logic and Logical Philosophy , 14: 69–88.
• –––, 2006, “Imagination’s Grip on Science”, Metaphilosophy , 37: 222–239.
• Dennett, Daniel C., 1984, Elbow Room: The Varieties of Free Will Worth Wanting , Cambridge: MIT Press.
• –––, 1991, Consciousness Explained , New York: Little Brown.
• –––, 1995, “Intuition Pumps”, in J. Brockman (ed.), The Third Culture , New York et al.: Simon & Schuster, 181–197.
• –––, 2005, Sweet Dreams , Cambridge, MA: MIT Press.
• DePaul, Michael, and William Ramsey (eds.), 2002, Rethinking Intuition: The Psychology of Intuition & Its Role in Philosophical Inquiry , Lanham: Rowman & Littlefield.
• Diamond, Cora, 2002, “What if X Isn’t the Number of Sheep? Wittgenstein and Thought-Experiments in Ethics”, Philosophical Papers , 31: 227–250.
• Di Paolo, E. A. et al., 2000, “Simulation Models as Opaque Thought Experiments”, in M. A. McCaskill et al. (eds.), Proceedings of the Seventh International Conference on Artificial Life , Cambridge: MIT Press, 497–506.
• Ducheyne, Steffen, 2006, “The Argument(s) for Universal Gravitation”, Foundations of Science , 11: 419–447.
• Duhem, Pierre, 1913, La théorie physique son objet et sa structure, 2 nd edition, Paris: Chevalier & Rivière, used here in reprint of 1981, Paris: Librairie Philosophique J. Vrin (translated by P. Weiner, 1960, Aim and Structure of Physical Theory , Princeton: Princeton University Press).
• El Skaf, Rawad, and Cyrille Imbert, 2013, “Unfolding in the Empirical Sciences: Experiments, Thought Experiments and Computer Simulations”, Synthese , 190: 3451–3474.
• Elgin, Catherine Z., 1993, “Understanding: Art and Science”, Synthese , 95: 13–28.
• –––, 1993b, “True Enough”, in Ernest Sosa and Enrique Villanueva (eds.), Epistemology: Philosophical Issues: Volume 14 , Boston, MA: Blackwell Publishing, 113–131.
• –––, 2007, “The Laboratory of the Mind”, in J. Gibson (ed.), A Sense of the World: Essays on Fiction, Narrative and Knowledge , Oxon: Routledge-Taylor Francis, 43–54.
• –––, 2014, “Fiction as Thought Experiment”, Perspectives on Science , 22: 221–241.
• Fehige, Yiftach J. H., 2012, “Experiments of Pure Reason. Kantianism and Thought Experiments in Science”, Epistemologia: Italian Journal for Philosophy of Science , 35: 141–160.
• –––, 2013, “The Relativized A Priori and the Laboratory of the Mind: Towards a Neo-Kantian Account of Thought Experiments in Science”, Epistemologia: Italian Journal for Philosophy of Science , 36: 55–63.
• –––, 2018, “Thought Experiments and Theology”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 183–194.
• –––, 2024, Thought Experiments, Science, and Religion , Leiden: Brill.
• –––, and Harald Wiltsche, 2013, “The Body, Thought Experiments, and Phenomenology”, in M. Frappier et al. (eds.), Thought Experiments in Philosophy, Science, and the Arts , London: Routledge, 69–89.
• –––, and Michael T. Stuart, 2014, “Origins of the Philosophy of Thought Experiments: The Forerun”, Perspectives on Science , 22: 179–220.
• Fisch, Menachem, 2017, Creatively Undecided: Toward a History and Philosophy of Scientific Agency , Chicago: Chicago University Press.
• –––, 2019, “Gulliver and the Rabbis: Counterfactual Truth in Science and the Talmud”, Religions: An Open Access Journal of Theology , https://doi.org/10.3390/rel10030228.
• Focquaert, Farah, 2003, “Personal Identity and its Boundaries: Philosophical Thought Experiments”, Philosophica , 72: 131–152.
• Fodor, Jerry, 1964, “On Knowing What We Would Say”, Philosophical Review , 73: 198–212.
• Frappier, Melanie, and Letitia Meynell, and James Robert Brown (eds.), 2013, Thought Experiments in Philosophy, Science, and the Arts , London: Routledge.
• Fuhrer, Therese, 2007, “Der Geist im Vollkommenen Körper: Ein Gedankenexperiment in Augustins De civitate 22”, in D. Frede and B. Reis (eds.), Body and Soul in Ancient Philosophy , Berlin: de Gruyter, 465–491.
• Gähde, Ulrich, 2000, “Gedankenexperimente in Erkenntnistheorie und Physik: Strukturelle Parallelen”, in J. Nida-Rümlin, Rationalität, Realismus, Revision , Berlin: de Gruyter, 457–464.
• Gendler, Tamar S., 1998, “Galileo and the Indispensability of Scientific Thought Experiment”, The British Journal for the Philosophy of Science , 49:397–424.
• –––, 2000, Thought Experiment: On the Powers and Limits of Imaginary Cases , New York: Garland Press (now Routledge).
• –––, 2002a, “Personal Identity and Thought-Experiments”, Philosophical Quarterly , 52: 34–54.
• –––, 2002b, “Thought Experiment”, Encyclopedia of Cognitive Science , New York; London: Nature/Routledge.
• –––, 2004, “Thought Experiments Rethought— and Reperceived”, Philosophy of Science , 71: 1152–1164.
• –––, 2005, “Thought Experiments in Science”, Encyclopedia of Philosophy , New York: MacMillan.
• –––, 2007, “Philosophical Thought Experiments, Intuitions, and Cognitive Equilibrium”, Midwest Studies in Philosophy of Science , 31: 68–89.
• Gendler, Tamar S., and John Hawthorne (eds.), 2002, Conceivability and Possibility. New York/Oxford: Clarendon/Oxford University Press.
• Genz, Henning, 1999, Gedankenexperimente , Weinheim: Wiley-VCH.
• Georgiou, Andreas, 2007, “An Embodied Cognition View of Imagery-Based Reasoning in Science: Lessons from Thought Experiments”, Croatian Journal of Philosophy , VII: 29–45.
• Glas, Eduard, 1999, “Thought Experimentation and Mathematical Innovation”, Studies in History and Philosophy of Science , 30: 1–19.
• Gomila, Antoni, 1991, “What is a Thought Experiment?”, Metaphilosophy , 22: 84–92.
• Gooding, David C., 1992, “The Cognitive Turn, or, Why Do Thought Experiments Work?”, in R. N. Giere (ed.), Cognitive Models of Science , Minneapolis: University of Minnesota Press, 45–76.
• –––, 1993, “What is Experimental About Thought Experiments?”, Proceedings of the Philosophy of Science Association , 2: 280–290.
• –––, 1994, “Imaginary Science”, British Journal for the Philosophy of Science , 45: 1029–1045.
• –––, 1999, “Thought Experiments”, in E. Craig (ed.), Encyclopedia of Philosophy: Volume 9 , London: Routledge, 392–397.
• Grant, Edward, 2007, “Thought Experiments and the Role of the Imagination”, in A History of Natural Philosophy: From the Ancient World to Nineteenth Century , Cambridge: Cambridge University Press, 200–211.
• Gregersen, Niels H., 2014, “The Role of Thought Experiments in Science and Religion”, in Michael Welker (ed.) Science and Religion: Past and Future , Frankfurt/Main: Peter Lang, 129–140.
• Grosdanoff, Boris, 2007, “Reconstruction, Justification and Incompatibility in Norton’s Account of Thought Experiments”, Croatian Journal of Philosophy , VII: 69–79.
• Grundmann, Thomas, 2018, “Plato and the A Priori in Thought Experiments”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 293–308.
• Grudmann, Thomas and Joachim Horvath, 2014, “Thought Experiments and the Problem of Deviant Realisations”, Philosophical Studies , 170(3): 525–533.
• Hacking, Ian, 1993, “Do Thought Experiments have a Life of Their Own?”, Proceedings of the Philosophy of Science Association , 2: 302–308.
• Häggqvist, Sören, 1996, Thought Experiments in Philosophy , Stockholm: Almqvist & Wiksell International.
• –––, 2007, “The A Priori Thesis: A critical Assessment”, Croatian Journal of Philosophy , VII: 47–61.
• –––, 2009, “A Model for Thought Experiments”, Canadian Journal of Philosophy , 39: 56–76.
• Hauerwas, Stanley, 1996,“Virtue, Description, and Friendship: A Thought Experiment in Catholic Moral Theology”, Irish Theological Quarterly , 62: 170–184.
• Helm, Hugh, and John Gilbert, 1985, “Thought Experiments and Physics Education – Part 1”, Physics Education , 20: 124–131.
• Helm, Hugh, and John Gilbert, and Michael D. Watts, 1985, “Thought Experiments and Physics Education – Part 2”, Physics Education , 20: 211–217.
• Herfeld, Catherine, 2019, “Imagination Rather Than Observation in Econometrics: Ragnar Frisch’s Hypothetical Experiments as Thought Experiments”, HOPOS: The Journal of the International Society for the History of Philosophy of Science , 9: 35–74.
• Hershenov, David B., 2008, “A Hylomorphic Account of Thought Experiments Concerning Personal Identity”, American Catholic Philosophical Quarterly , 82: 481–502.
• Hintikka, Jaakko, 1999, “The Emperor’s New Intuitions”, The Journal of Philosophy , 96: 127–147.
• Hitchcock, Christopher, 2012, “Thought Experiments, Real Experiments, and the Expertise Objection”, European Journal for Philosophy of Science , 2: 205–218.
• Hopp, Walter, 2014, “Experiments in Thought”, Perspectives on Science , 22: 242–263.
• Horowitz, Tamara, 1998, “Philosophical Intuitions and Psychological Theory”, Ethics , 108: 367–385.
• Horowitz, Tamara, and Gerald Massey (eds.), 1991, Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield.
• Humphreys, Paul, 1993, “Seven Theses on Thought Experiments”, in J. Earman et al . (eds.), Philosophical Problems of the Internal and External World , Pittsburgh: University of Pittsburgh Press, 205–227.
• Ichikawa, Jonathan, and Benjamin Jarvis, 2009, “Thought-experiment Intuition and truth in Fiction”, Philosophical Studies , 142: 221–246.
• Ierodiakonou, Katerina, 2005, “Ancient Thought Experiments: A First Approach”, Ancient Philosophy , 25: 125–140.
• –––, 2018, “The Triple Life of Ancient Thought Experiments”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 31–43.
• Ierodiakonou, Katerina, and Sophia Roux (eds.), 2011, Thought Experiments in Methodological and Historical Contexts , Leiden: Brill.
• Inwagen, Peter van, 1998, “Modal Epistemology”, Philosophical Studies , 92: 67–84.
• Irvine, Andrew D., 1991, “Thought Experiments in Scientific Reasoning”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 149–166.
• Jackson, Frank, 1982, “Epiphenomenal Qualia”, Philosophical Quarterly , 32: 27–36.
• –––, 2009, “Thought Experiments and Possibilities”, Analysis , 69: 100–109.
• Jackson, M. W., 1992, “The Gedankenexperiment Method of Ethics”, The Journal of Value Inquiry , 26: 525–535.
• Janis, Allen I., 1991, “Can Thought Experiments Fail?”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 113–118.
• Kalin, Martin G., 1972, “Kant’s Transcendental Arguments as Gedankenexperimente”, Kant Studien , 63: 315–328.
• Kassung, Christian, 2004, “Tichy · 2 = ?: Relativitätstheorie als literarisches Gedankenexperiment”, in T. Macho and A. Wunschel (eds.), Science & Fiction , Frankfurt am Main: Fischer, pp. 17–32.
• Kertesz, Andras, 2015, “The Puzzle of Thought Experiments in Conceptual Metaphor Research”, Foundations of Science , 20: 147–174.
• King, Peter, 1991, “Mediaeval Thought-Experiments: The Metamethodology of Mediaeval Science”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 43–64.
• Klassen, Stephen, 2006, “The Science Thought Experiment: How Might it be Used Profitably in the Classroom?”, Interchange , 37: 77–96.
• Klee, Robert, 2008, “Physical Scale Effects and Philosophical Thought Experiments”, Metaphilosophy , 39: 89–104.
• Knox, Philip, and Jonathan Morton, and Daniel Reeve (eds.), 2018, Medieval Thought Experiments: Poetry, Hypothesis, and Experience in the European Middle Ages , Turnhout, Belgium : Brepols.
• Kolak, Daniel, 1993, “Metaphysics and Metapsychology of Personal Identity: Why Thought Experiments Matter in Deciding Who We Are”, American Philosophical Quarterly , 30: 39–50.
• Koyré, Alexandre, 1968, Metaphysics and Measurement , London: Chapman and Hall.
• Krauthausen, Karin, 2015, “Ermittlung der Empirie: Zu Ernst Machs Methode des Gedankenexperiments”, Berichte zur Wissenschaftsgeschichte , 38: 15–40.
• Krimsky, Sheldon, 1973, “The Use and Misuse of Critical Gedankenexperimente”, Zeitschrift für allgemeine Wissenschaftstheorie , 4: 323–334.
• Kuhn, Thomas S., 1964, “A Function for Thought Experiments”, reprinted in T. Kuhn, The Essential Tension , Chicago: University of Chicago Press, 1977, 240–265.
• Kühne, Ulrich, 2005, Die Methode des Gedankenexperiments , Frankfurt: Suhrkamp.
• Kujundzic, Nebojsa, 1995, “Thought Experiments: Architecture and Economy of Thought”, The Journal of the British Society for Phenomenology , 26: 86–93.
• –––, 1998, “The Role of Variation in Thought Experiments”, International Studies in the Philosophy of Science , 12: 239–243.
• –––, 2013, “Thought Experiments, Puzzles, and Paradoxes”, Philosophy Study , 3: 750–758.
• Kukkonen, Taneli, 2014, “Ibn Sina and the Early History of Thought Experiments”, Journal of the History of Philosophy , 53: 433–453.
• Laymon, Ronald, 1991, “Thought Experiments of Stevin, Mach and Gouy: Thought Experiments as Ideal Limits and as Semantic Domains”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 167–192.
• Lenhard, Johannes, 2011, “Epistemologie der Iteration: Gedankenexperimente und Simulationsexperimente”, Deutsche Zeitschrift für Philosophie , 59: 131–154.
• Lennox, James G., 1991, “Darwinian Thought Experiments: A Function for Just-So Stories”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 223–245.
• Ludwig, Kirk, 2007, “The Epistemology of Thought Experiments: First Person versus Third Person Appraoches”, Midwest Studies in Philosophy , 31: 128–159.
• –––, 2018, “Thought Experiments and Experimental Philosophy”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 385–405.
• Maar, Alexander, 2014, “Possible Uses of Counterfactual Thought Experiments in History”, Principia , 18: 87–113.
• Mach, Ernst, 1883, Die Mechanik in ihrer Entwicklung: Historisch-Kritisch Dargestellt , seventh edition, used here in reprint of 1988, Berlin; Akademie Verlag (trans. by J. McCormack, The Science of Mechanics , LaSalle Illinois: Open Court).
• –––, 1897, “Über Gedankenexperimente”, in: Zeitschrift für den physikalischen und chemischen Unterricht , 10: 1–5.
• –––, 1905, “Über Gedankenexperimente”, in Erkenntnis und Irrtum , Leipzig: Verlag von Johann Ambrosius Barth, 181–197, (translated by J. McCormack, in Knowledge and Error , Dordrecht: Reidel, 134–147).
• Macho, Thomas, and Anette Wunschel (eds.), 2004, Science and Fiction:Über Gedankenexperimente in Wissenschaft, Philosophie und Literatur , Frankfurt am Main: Fischer Verlag.
• Machery, Edouard, 2011,“Thought Experiments and Philosophical Knowledge”, Metaphilosophy , 42: 191–214.
• Maffie, James, 1997, “Just-so Stories about ‘Inner Cognitive Africa’: Some Doubts about Sorensen’s Evolutionary Epistemology of Thought Experiments”, Biology and Philosophy , 12: 207–224.
• Malmgren, Anna-Sara, 2011, “Rationalism and the Content of Intuitive Judgements”, Mind , 120: 263–327.
• Massey, Gerald, 1991, “Backdoor Analyticity”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 285–296.
• Mayer, Verena, 1999, “Was zeigen Gedankenexperimente?”, Philosophisches Jahrbuch , 106: 357–378.
• McAllister, James, 1996, “The Evidential Significance of Thought Experiments in Science”, Studies in History and Philosophy of Science , 27: 233–250.
• –––, 2004, “Thought Experiments and the Belief in Phenomena”, Proceedings of the 2002 Biennial Meeting of the Philosophy of Science Association, Philosophy of Science , 71: 1164–1175.
• –––, 2005, “The Virtual Laboratory: Thought Experiments in Seventeenth-Century Mechanics”, in H. Schramm et al. (eds.), Collection, Laboratory, Theater: Scenes of Knowledge in the 17th Century , New York: Walter de Gruyter, 35–56.
• McComb, Geordie, 2013, “Thought Experiment, Definition, and Literary Fiction”, in M. Frappier et al. (eds.), Thought Experiments in Philosophy, Science, and the Arts , London: Routledge, 207–222.
• McGinnis, Jon, 2018, “Experimental Thoughts on Thought Experiments in Medieval Islam”, in Michael T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 77–91.
• McMullin, Ernan, 1985, “Galilean Idealization”, Studies in History and Philosophy of Science , 16: 247–273.
• Meinong, Alexius, 1907, “Das Gedankenexperiment”, in Über die Stellung der Gegenstandstheorie im System der Wissenschaften (reprinted in the fifth volume of the collected works of Meinong, edited by Rudolf Haller and Rudolf Kindinger, Graz-Austria: Akademische Druck und Verlagsanstalt, 1973, 273–283 [67–77]).
• Meixner, Uwe, 2000, “On Some Realisms Most Realists Don’t Like”, Metaphysica , 1: 73–94.
• Malament, David B., 2008, “Norton’s Slippery Slope”, Philosophy of Science , 75: 799–818.
• Meynell, Letitia, 2014, “Imagination and Insight: A new Acount [sic!] of the Content of Thought Experiments”, Synthese , 191: 4149–4168.
• Milligan, Tony, 2019, “Thought Experiments and Novels”, Studia Humana , 8: 84–92.
• Miščević, Nenad, 2021, Thought Experiments , Cham: Springer.
• –––, 1992, “Mental Models and Thought Experiments”, International Studies in the Philosophy of Science , 6: 215–226.
• –––, 1997, “Categorial and Essentialist Intuitions: A Naturalist Perspective”, Acta Analytica , 12: 21–39.
• –––, 2004, “The Explainability of Intuitions”, dialectica , 58: 43–70.
• –––, 2007, “Modelling Intuitions and Thought Experiments”, Croatian Journal of Philosophy , VII: 181–214.
• Morrison, Margaret, 2009, “Models, Measurements, and Computer Simulations: the Changing Face of Experimentation”, Philosophical Studies , 143: 33–57.
• Moue, Aspasia S. et al., 2006, “Tracing the Development of Thought Experiments in the Philosophy of the Natural Sciences”, Journal for General Philosophy of Science , 37: 61–75.
• Myers, Mason C., 1968, “Thought Experiments and Secret Stores of Information”, International Philosophical Quarterly , 8: 180–192.
• –––, 1986, “Analytical Thought Experiments”, Metaphilosophy , 17: 109–118.
• Myers, David G., 2004), Intuition. Its powers and perils , New Haven; London: Yale University Press.
• Nersessian, Nancy, 1992, “How Do Scientists Think? Capturing the Dynamics of Conceptual Change in Science”, in R. Giere (ed.), Cognitive Models of Science , Minneapolis: University of Minnesota Press, 3–44.
• –––, 1993, “In the Theoretician’s Laboratory: Thought Experimenting as Mental Modeling”, Proceedings of the Philosophy of Science Association , 2: 291–301.
• –––, 2007, “Thought Experiments as Mental Modelling: Empiricism without Logic”, Croatian Journal of Philosophy , VII: 125–161.
• –––, 2018, “Cognitive Science, Mental Models, and Thought Experiments”, in Michael T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 309–326.
• Norton, John D., 1991, “Thought Experiments in Einstein’s Work”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 129–148.
• –––, 1993, “Einstein and Nordström: Some lesser known Thought Experiments in Gravitation”, in J. Earman et al. (eds.), The Attraction of Gravitation: New Studies in History of General Relativity , Boston: Birkhäuser, 3–29.
• –––, 1993b, “Seeing the Laws of Nature”, Metascience , 3:33–38.
• –––, 1996, “Are Thought Experiments Just What You Thought?”, Canadian Journal of Philosophy , 26: 333–366.
• –––, 2004a, “On Thought Experiments: Is There More to the Argument?” Proceedings of the 2002 Biennial Meeting of the Philosophy of Science Association, Philosophy of Science , 71: 1139–1151. [ Preprint available online ].
• –––, 2004b, “Why Thought Experiments Do Not Transcend Empiricism”, in C. Hitchcock (ed.), Contemporary Debates in the Philosophy of Science , Oxford: Blackwell, 44–66. [ Preprint available online ].
• –––, 2008, “The Dome: An Unexpectedly Simple Failure of Determinism”, Philosophy of Science , 75: 786–798.
• Ornelas, J., A. Cintora, and P. Hernandez, 2018, Trabajando en el Laboratorio de la Mente: Naturaleza y Alcance de los Experimento Mentales , San Luis Potosí: Universidad Autónoma de San Luis Potosí.
• Palmer, Anthony, 1984, “The Limits of AI: Thought Experiments and Conceptual investigations”, in S. Torrance (ed.), The Mind and the Machine: Philosophical Aspects of Artificial Intelligence , Chichester: Ellis Horwood, pp. 43–50.
• Palmieri, Paolo, 2003, “Mental Models in Galileo’s Early Mathematization of Nature”, Studies in History and Philosophy of Science , 34: 229–264.
• –––, 2005, “‘Spuntur lo scoglio più duro’: Did Galileo Ever Think the Most Beautiful Thought experiment in the History of Science?”, Studies in History and Philosophy of Science , 36: 305–322.
• Parfit, Derek, 1987, Reasons and Persons , Oxford: Clarendon Press.
• Peijnenburg, Jeanne, and David Atkinson, 2003, “When are Thought experiments Poor Ones?”, Journal for General Philosophy of Science , 34: 305–322.
• –––, 2007, “On poor and not so Poor Thought experiments: A reply to Daniel Cohnitz”, Journal for General Philosophy of Science , 38: 159–161.
• Perler, Dominik, 2008, “Thought Experiments: The Methodological Function of Angels in Late Medieval Epistemology”, in Isabel Iribarren and Markus Lenz (eds.), Angels in Medieval Philosophical Inquiry , Aldershot: Ashgate, 143–153.
• Picha, Marek, 2011, Kdyby chyby. Epistemologie myšlenkových experimentů , Olomouc: Nakladatelství Olomouc.
• Popper, Karl, 1959, “On the Use and Misuse of Imaginary Experiments, especially in Quantum Theory”, in The Logic of Scientific Discovery , London: Hutchinson, 442–456.
• Poser, Hans, 1984, “Wovon handelt ein Gedankenexperiment?”, in H. P. Poser and H.-W. Schütt (eds.), Ontologie und Wissenschaft. Philosophische und wissenschaftliche Untersuchungen zur Frage der Objektkonstruktion , Berlin: TUB-Dokumentationen, Issue 19: 181–198.
• Praem, Sara Kier, and Asbjorn Steglich–Petersen, 2015, “Philosophical Thought Experiments as Heuristics for Theory Discovery”, Synthese , 192: 2827–2842.
• Prudovsky, Gad, 1989, “The Confirmation of the Superposition Principle: The Role of a Constructive Thought Experiment in Galileo’s Discorsi” , Studies in History and Philosophy of Science , 20: 453–468.
• Pulte, Helmut, 2007, “Gedankenexperiment und Physikalisches Weltbild: Überlegungen zur Bildung von Naturwissenschaft und zur naturwissenschaftlichen Bildung im Anschluss an A. Einstein”, in Die Kultur moderner Wissenschaft am Beispiel Albert Einstein , München: Akademie Verlag, 39–68.
• Puskaric, Ksenija, 2007, “Brown and Berkeley”, Croatian Journal of Philosophy , VII: 177–180.
• Rehder, Wulf, 1980a, “Thought Experiment and Modal Logic”, Logique et Analyse , 23: 407–417.
• –––, 1980b, “Versuche zu einer Theorie von Gedankenexperimenten”, Grazer Philosophische Studien , 11: 105–123.
• Reiss, Julian, 2009, “Counterfactuals, Thought Experiments and Singular Causal Inference in History”, Philosophy of Science , 76: 712–723.
• –––, 2013, “Genealogical Thought Experiments in Economics”, in M. Frappier et al. (eds.), Thought Experiments in Philosophy, Science, and the Arts , London: Routledge, 177–190.
• Rescher, Nicholas, 1991, “Thought Experiments in Presocratic Philosophy”, in T. Horowitz and G. Massey (eds.), Thought Experiments in Science and Philosophy , Lanham: Rowman & Littlefield, 31–42.
• –––, 2003, Imagining Irreality , Chicago; La Salle: Open Court.
• –––, 2005, What If?: Thought Experimentation in Philosophy , New Brunswick, NJ: Transaction Publishers.
• Roberts, Francis, 1993, “Thought Experiments and Social Transformation”, Journal for the Theory of Social Behaviour , 23: 399–421.
• Robinson, Howard, 2004, “Thought Experiments, Ontology and Concept-Dependent Truthmakers”, Monist , 87: 537–553.
• Saam, Nicole J., 2017, “What is a Computer Simulation? A Review of a Passionate Debate”, Journal for General Philosophy of Science , 48: 293–309.
• Saint-Germier, Pierre, forthcoming, “Getting Gettier Straight: Thought Experiments, Deviant Realizations and Default Interpretations”, Synthese .
• Schabas, Margaret, 2008, “Hume’s Monetary Thought Experiments”, Studies in History and Philosophy of Science , 39: 161–168.
• Schildknecht, Christiane, 1990, Philosophische Masken: Literarische Formen der Philosophie bei Platon, Descartes, Wolff und Lichtenberg , Stuttgart: Metzler.
• Schlesinger, George N., 1995, “The Power of Thought Experiments”, Foundations of Physics , 26: 467–482.
• Schöne, A., 1982, Aufklärung aus dem Geist der Experimentalphysik: Lichtenbergsche Konjunktive , München: C. H. Beck.
• Schrödinger, E., 1935, “The Present Situation in Quantum Mechanics”, trans in J. Wheeler and W. Zurek (eds.), Quantum Theory and Measurement , Princeton: Princeton University Press.
• Schulzke, Marcus, 2014, “Simulating Philosophy: Interpreting Video Games as Executable Thought Experiments”, Philosophy and Technology , 27: 251–265.
• Shafer, Michael J., 2017, “’Filling In’, Thought Experiments and Intuitions”, Episteme , 14: 255–262.
• Shepard, Roger N., 2008, “The Step to Rationality: The Efficacy of Thought Experiments in Science, Ethics, and Free Will”, Cognitive Science , 32: 3–335.
• Snooks, R. J., 2006, “Another Scientific Practice Separating Chemistry from Physics”, Foundations of Chemistry , 8: 255–270.
• Sorensen, Roy A., 1992, Thought Experiments , Oxford: Oxford University Press.
• Souder, Lawrence, 2003, “What are we to think about Thought Experiments?”, Argumentation: An International Journal on Reasoning , 17: 203–217.
• Sriraman, Bharath, 2006, “An Ode to Imre Lakatos: Quasi-Thought Experiments to Bridge the Ideal and Actual Mathematics Classrooms”, Interchange , 37: 151–178.
• Starikova, Irina, 2007, “Proofs and Pictures”, Croatian Journal of Philosophy , VII: 81–92.
• Stern, J. P., 1963, Lichtenberg: A Doctrine of Scattered Occassions , London: Thames and Hudson.
• Stich, Stephen, and Kevin Toba, 2018, “Intuition and Its Critics”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 369–384.
• Stinner, Arthur, 1990, “Philosophy, Thought Experiments, and Large Context Problems in the Secondary Physics Course”, International Journal of Science Education , 12: 244–157.
• Stöltzner, Michael, 2003, “The Dynamics of Thought Experiments-Comment to Atkinson”, in M. Galavotti (ed.), Observation and Experiment in the Natural and Social Sciences , Kluwer: Dordrecht, 2003, 243–258.
• Stuart, Michael T., 2014, “Cognitive Science and Thought Experiments: A Refutation of Paul Thagard’s Skepticism”, Perspectives on Science , 22: 264–287.
• –––, 2016, “Taming theory with Thought Experiments: Understanding and Scientific Progress”, Studies in History and Philosophy of Science , 58: 24–33.
• –––, 2016b, “Norton and the Logic of Thought Experiments”, Axiomathes , 26: 451–466.
• –––, 2017, “Imagination: A Sine Qua Non of Science”, Croatian Journal of Philosophy , XVII: 9–32.
• –––, 2018, “How Thought Experiments Increase Understanding”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 526–544.
• –––, 2021, “Towards a Dual Process Epistemology of Imagination”, Synthese , 198: 1329–1350.
• Stuart, Michael T., Yiftach Fehige, and James R. Brown (eds.), 2018, The Routledge Companion to Thought Experiments , London and New York: Routledge.
• Swirski, Peter, 2007, Of Literature and Knowledge: Explorations in Narrative Thought Experiments, Evolution and Game Theory , London & New York: Routledge.
• Taliaferro, Charles, 2001, “Sensibility and Possibilia: A Defense of Thought Experiments”, Philosophia Christi , 3: 403–420.
• –––, and Elliot Knuths, 2017, “Thought Experiments in Philosophy of Religion: The Virtues of Phenomenological Realism and Values”, Open Theology , 3: 167–173.
• Tetlock, Philip E. et al. (eds.), 2009, Unmaking the West: What-If? Scenarios That Rewrite World History , Ann Arbor: University of Michigan Press.
• Thagard, Paul, 2014, “Thought Experiments Considered Harmful”, Perspectives on Science , 22: 288–305.
• Thaler, Mathias, 2016, “Unhinged Frames: Assessing Thought Experiments in Normative Political Theory”, British Journal of Political Science , 48: 1119–1141.
• Thoma, Johanna, 2016, “On the Hidden Thought Experiments of Economic Theory”, Philosophy of the Social Sciences , 46: 129–146.
• Thomson, Judith Jarvis, 1971, “A Defense of Abortion”, Philosophy and Public Affairs , 1: 47–66.
• Urbaniak, Rafal, 2012, “”Platonic“ Thought Experiments: How on Earth?”, Synthese , 187: 731–752.
• Urbaniec, Jacek, 1988, “In Search of a Philosophical Experiment”, Metaphilosophy , 19: 294–306.
• Van Bendegem, Jean Paul, 2003, “Thought Experiments in Mathematics: Anything But Proof”, Philosophica , 72: 9–33.
• Van Dyck, Maarten, 2003, “The Roles of One Thought Experiment in Interpreting Quantum Mechanics: Werner Heisenberg Meets Thomas Kuhn”, Philosophica , 72: 1–21.
• Walsh, Adrian, 2011, “A Moderate Defence of the Use of Thought Experiments in Applied Ethics”, Ethical Theory and Moral Practice , 14: 467–481.
• Weber, Erik, and Tim DeMey, 2003, “Explanation and Thought Experiments in History”, History and Theory , 42: 28–38.
• Wilkes, Kathleen V., 1988, Real People: Personal Identity without Thought Experiments , Oxford: Oxford University Press.
• Williamson, Timothy, 2004a, “Armchair Philosophy, Metaphysical Modality and Counterfactual Thinking”, Proceedings of the Aristotelian Society , CV: 1–23.
• –––, 2004b, “Philosophical ‘Intuitions’ and Scepticism about Judgement”, dialectica , 58: 109–153.
• –––, 2008, The Philosophy of Philosophy , Malden, MA, et al: Blackwell.
• –––, 2009, “Replies to Kornblinth, Jackson and Moore 1”, Analysis , 69: 125–135.
• Wilson, James, 2016, “VII–Internal Validity and External Validity in Thought Experiments”, Proceedings of the Aristotelian Society , CXVI: 127–152.
• Wiltsche, Harald, 2018, “Phenomenology and Thought Experiments: Thought Experiments as Anticipation Pumps”, in M. T. Stuart et al. (eds.), The Routledge Companion to Thought Experiments , London and New York: Routledge, 342–365.
• Winchester, Ian, 1990, “Thought Experiments and Conceptual Revision”, Studies in Philosophy and Education , 10: 73–80.
• Witt-Hansen, Johannes, 1976, “H. C. Orsted, Kant and The Thought Experiment”, Danish Yearbook of Philosophy , 13: 48–56.
• Ylikoski, Petri, 2003, “Thought Experiments in Science Studies”, Philosophica , 72: 35–59.
• Young, Garry, 2013, Philosophical Psychopathology: Philosophy Without Thought Experiments , Hampshire, UK: Palgrave Macmillan.
• Yourgrau, Wolfgang, 1964, “On the Logical Status of so-called Thought Experiments”, Proceedings of the Xth International Congress of the History of Science , Paris: Herman, 359–362.
• –––, 1967, “On models and thought experiments in quantum theory”, Monatsberichte der Deutschen Akademie der Wissenschaften zu Berlin , 9: 886–874.

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• Thought Experiments , entry in the Oxford Bibliographies , by James R. Brown and Michael T. Stuart.
• Thought Experiments and Religion , entry in the Oxford Encyclopedia of Religion , by Yiftach Fehige.
• Goodies , a collection of intriguing questions in the philosophy of science, some about thought experiments, by John Norton.
• An Interactive Version of Thomson’s violin thought experiment .
• Six famous thought Experiments Explained Quickly , a video tutorial.
• Ethical Thought Experiments Like the Trolley Dilemma , a video tutorial.

Descartes, René | Galileo Galilei | intuition | Leibniz, Gottfried Wilhelm | Mach, Ernst | moral psychology: empirical approaches | Platonism: in metaphysics | rationalism vs. empiricism

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Einstein's Problem Solving Skills: 5 Ways to Think

Albert Einstein was an iconic figure whose legacy remains to this day. This article explores five key ways Einstein thought, as revealed in three biographies of his life: visualization, combinatory play, intuition, imagination, and Gedanken experiments. These strategies allowed Einstein to make connections between seemingly unrelated ideas and explore the implications of his theories without the need for physical experiments or data. Einstein made groundbreaking discoveries through these strategies and shaped how we think about the world and the universe.

Introduction

Three biographies of Einstein

Five ways he thought

Visualization

Conjuring up a “picture” of the phenomena

Albert Einstein is one of the most iconic figures in history, and his legacy remains. His revolutionary theories and discoveries have shaped how we think about the world and the universe. While much has been written about Einstein's life and work, many aspects of his thinking remain a mystery. This article will explore five key ways Einstein thought, as revealed in three biographies of his life.

Visualization was one of the essential aspects of Einstein's thinking process.

He worked hard to conjure up a “picture” of the phenomenon he was investigating and waited for the image to reveal itself through action and interaction. This allowed him to gain a deeper understanding of the problem and make connections that he may not have been able to make otherwise.

The combinatory play was another essential way that Einstein thought. This involved bringing disparate pieces together in unpredictable combinations and exploring the outcomes. This allowed him to connect seemingly unrelated ideas and make unexpected discoveries.

Intuition was also an essential part of Einstein's thinking process. He believed in allowing his intuition free rein and accepting the results without explaining or questioning them. This allowed him to make leaps of logic that were not based on facts or data but on his internal understanding of the problem.

Imagination was also crucial to Einstein's thinking process. He believed that imagination was more important than knowledge and the key to unlocking new ideas and insights. He encouraged himself to open the gates to new thoughts and explore their possibilities of them.

Finally, Einstein relied heavily on Gedanken experiments. These experiments allow him to imagine a situation and explore the potential outcomes. This allowed him to explore the implications of his theories without the need for physical experiments or data.

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In conclusion, the five key ways in which Einstein thought are visualization, combinatory play, intuition, imagination, and Gedanken experiments. These strategies allowed him to connect seemingly unrelated ideas and explore the implications of his theories without the need for physical experiments or data. By utilizing these five strategies, Einstein made groundbreaking discoveries and shaped the way we think about the world and the universe.

Creative problem-solving begins with a willingness to think differently. -Albert Einstein IIENSTITU

What are the five ways Einstein used to think?

Albert Einstein, one of the most renowned physicists of all time, has been credited with numerous scientific breakthroughs, such as the Theory of Relativity. His numerous contributions to science have been documented in various books and articles. However, the methods behind his success remain a mystery. This article will discuss five of how Einstein thought, known as the "Einstein Method."

The first step in the Einstein Method is to think broadly. He was known to be a master of connecting seemingly unrelated concepts and topics, allowing him to make discoveries that otherwise would have been overlooked. He could also transform seemingly mundane ideas into something truly revolutionary.

The second step of the Einstein Method is to question everything. Einstein was a deep thinker and was not afraid to ask difficult questions, even if he didn't have the answers. He could take seemingly simple ideas and ask "why" until he deeply understood the underlying concepts.

The third step of the Einstein Method is to remain persistent and patient. Einstein was willing to take the time to carefully consider and analyze a problem, even if it took him months or years. He was also ready to make mistakes to learn and was not afraid to start from scratch if he was unsatisfied with the results.

The fourth step of the Einstein Method is to think outside the box. He was known to be a master of lateral thinking and was unafraid to consider unconventional theories or ideas. He was also willing to challenge conventional wisdom and accepted views if he believed something more was to be discovered.

The fifth and final step of the Einstein Method is to think deeply. Einstein was known for his ability to go beyond the surface level of a problem and explore the underlying concepts. He was willing to challenge the status quo and look for new solutions to old problems.

In conclusion, Albert Einstein's genius resulted from his ability to think in five distinct ways. He could think broadly, question everything, remain persistent and patient, think outside the box, and think deeply. These five steps of the Einstein Method have been proven time and time again to be highly effective in solving complex problems.

How did Einstein use visualization to solve problems?

Albert Einstein is widely regarded as one of the most brilliant minds of the twentieth century. His theories of relativity and quantum mechanics have been studied and expanded upon by scientists for decades. However, Einstein was not only a brilliant scientist but also an inventor and a master of visualization. He was able to use visualization to help him solve complex problems.

Visualization is a process in which one imagines a problem and visualizes the solution in their head. This allows a person to understand a problem's underlying principles better and come up with creative solutions. Einstein was a master of this technique, which is widely believed to be one of the critical factors that allowed him to develop his revolutionary theories.

One example of how Einstein used visualization to solve a problem can be seen in his work on the theory of special relativity. Einstein applied visualization principles to understand the approach by imagining himself riding on a light beam. This allowed him to conceptualize the idea of time dilation, a critical concept of special relativity.

Einstein also used visualization to help him understand the concept of space-time. To do this, he imagined a four-dimensional world in which time and space were intertwined. This allowed him to visualize the curved nature of space-time and the effects of gravity on it. This visualization permitted Einstein to understand and develop the general theory of relativity.

Einstein also utilized the power of visualization in his work on quantum mechanics. For example, he used visualization to help him understand the wave-particle duality of light and the uncertainty principle. By visualizing these concepts, Einstein was able to gain a better understanding of these complex principles.

Einstein's mastery of visualization was one of the critical factors that allowed him to develop revolutionary theories. His ability to imagine and visualize solutions to complex problems enabled him to see beyond the boundaries of traditional scientific thinking. This is one of the key reasons why he is regarded as one of the greatest scientific minds of all time.

How did Einstein use intuition and imagination to solve problems?

Albert Einstein was one of the most renowned scientists of the 20th century and was famous for his use of intuition and imagination to solve problems. He believed the ability to think imaginatively and intuitively was essential to scientific exploration. He used his intuition and creativity to develop innovative ideas and theories.

Einstein attributed his successes to his creative imagination and intuition. He believed creativity and intuition could be used to develop new theories and solve complex problems. He argued that intuition was an invaluable aid in developing scientific theories, as it allowed him to think outside the box and create ideas that were not constrained by traditional methods of inquiry.

Einstein used his intuition and imagination to develop his Theory of Relativity. First, he observed the motion of light and used his intuition and creativity to formulate an equation describing light's behavior. He then used his intuition to develop a mathematical model to explain light behavior. Einstein's Theory of Relativity revolutionized physics and is still used to describe the universe's behavior today.

Einstein also used his intuition and imagination to develop his Unified Field Theory. First, he used his intuition to identify the fundamental forces that govern the universe. He then used his vision to create a mathematical model that would describe the behavior of these forces.

Einstein's use of intuition and imagination to solve problems was instrumental in his success as a scientist. He believed that intuition and imagination were essential tools for scientific exploration. He used his intuition and imagination to develop new theories and solve complex problems. His use of intuition and imagination to solve problems revolutionized physics and remains an essential tool for scientific exploration today.

What are the five strategies of problem-solving in the context of academic research?

Akademik Araştırmada Problem Çözme Stratejileri 1. Problemi Tanımlama Akademik araştırmada problem çözmenin ilk adımı, problemin ne olduğunu açık ve kesin bir şekilde tanımlamaktır. Bu, araştırmanın temel sorusunu ve amacını belirleyerek başlar ve ardından sorunun nedenleri ve etkileri üzerinde odaklanmayı gerektirir. 2. Bilgi Toplama Problem çözmeye yönelik bir diğer strateji, sorunun anlaşılması ve çözülmesi için gereken bilgileri toplamaktır. Bu süreç, mevcut literatürü incelemeyi, daha önce yapılmış çalışmalardan ve uzman görüşlerinden yararlanmayı içerir. 3. Alternatif Çözüm Yolları Geliştirme Bir sonraki adım, problemi çözmek için farklı çözüm yollarını düşünmek ve değerlendirmektir. Bu, farklı yaklaşımları ve metodolojileri kullanarak, soruna birden fazla açıdan yaklaşmayı ve uygun çözümleri belirlemeyi içerir. 4. Çözümün Uygulanması Araştırmada problem çözmenin dördüncü stratejisi, seçilen çözüm yolu üzerinde çalışmaya başlamaktır. Bu süreç, gerekli verileri toplamayı, analiz etmeyi ve sonuçları yorumlamayı içerir. 5. Değerlendirme ve Revizyon Son olarak, problem çözme süreci içinde değerlendirmeyi ve revizyonu da içerir. Bu aşamada, çözümün etkili ve uygun olduğuna dair kanıtlar toplanarak, daha ileri araştırma veya uygulama için herhangi bir değişiklik yapılması gerekip gerekmediğini belirlemek önemlidir. Sonuç olarak, akademik araştırmada problem çözme stratejileri, problemin doğru bir şekilde tanımlanması, bilgi toplanması, alternatif çözüm yollarının geliştirilmesi, çözümün uygulanması ve sonuçların değerlendirilmesi ve gerektiğinde revize edilmesine dayanmaktadır. Bu stratejiler, araştırmacılara, problemleri etkili bir şekilde ele almak ve çözmek için gereken araçları sağlar.

In relation to Einstein's approach to problem-solving, can you explain his perspective on thinking differently to tackle complex issues?

Einstein'ın Problem Çözme Yaklaşımı Albert Einstein tarafından sıklıkla dile getirilen farklı düşünme anlayışı, problem çözmeye etkileyici ve yenilikçi bir yaklaşım sunar. Einstein, mevcut düşünce kalıplarını ve normları aşarak, karmaşık sorunlara çözüm getirebilecek yaratıcı ve özgün düşüncelere ulaşmanın önemini vurgular. Karmaşık Sorunlara Farklı Bakış Açısı Einstein, 'Bir sorunu yaratmak için kullanılan düşünce tarzını kullanarak çözüm bulamazsınız' şeklinde bir yaklaşım benimsemiştir. Bu, mevcut sorunları anlamak ve çözmek için farklı perspektiflerden, disiplinlerarası bilgi ve yöntemlerle yaklaşmak gerektiği anlamına gelir. Yaratıcılığın Rolü Einstein, yaratıcılığın bilim ve problem çözmedeki önemine inanıyor ve kendi başarılarında bu özelliğin büyük rolü olduğunu dile getiriyordu. Yaratıcılık ve hayal gücünün, bilimsel keşiflerin ve yeni fikirlerin birincil kaynağı olduğunu savunuyordu. Aşamalı Düşünme Metodu Einstein'ın problem çözme yöntemine göre, karmaşık sorunların üstesinden gelmek için aşamalı bir düşünme süreci benimsemek gereklidir. Farklı düşünme aşamaları, bilinmeyenlere odaklanmak ve problemi daha geniş ve bütünsel bir çerçevede görüp analiz etmeyi içerir. Deneyerek Öğrenme Einstein, bilgiyi deneyim yoluyla elde etme anlayışına sahipti. Yeni fikirler ve çözümler üretmek için yalnızca teorik bilgiden değil, öğrenmek ve yenilikleri deneyerek hedefe ulaşma sürecinin önemini vurguladı. Sonuç olarak, Einstein'ın problem çözme yaklaşımı, karmaşık konuları ele alırken farklı düşünme, yaratıcılık, aşamalı düşünme ve deneyimle öğrenme yöntemleri sayesinde başarılı sonuçlar elde etmeyi önerir. Bu yaklaşım, günümüz dünyasında bilgi patlaması ve değişen paradigmalarla birlikte düşünme ve problem çözme becerilerinin geliştirilmesinde hâlâ büyük öneme sahiptir.

How does adopting a problem-solving mindset contribute to better understanding and resolving challenges in various academic disciplines?

Sorun Çözme Odaklı Zihniyetin Önemi Farklı akademik disiplinlerdeki zorlukları anlamak ve çözmek için sorun çözme odaklı bir zihniyet benimsemek, önemli ölçüde katkıda bulunur. Bu zihniyet, öğrencilerin bulundukları alanın karmaşıklığını ve değişkenlerini daha iyi kavramalarını sağlar. Analitik Düşünce Geliştirme Sorun çözme odaklı düşünce, analitik düşünme becerilerini geliştirir. Bu sayede, öğrenciler problemleri daha kapsamlı olarak değerlendirebilir ve her durum için en uygun stratejileri belirleyebilirler. Yaratıcı Yaklaşımların Teşvik Edilmesi Sorun çözmeye yönelik zihniyet, yaratıcılığı ve yenilikçi düşünceyi teşvik eder. Çeşitli akademik disiplinlerde yeni ve etkili yöntemlerin keşfi için yaratıcı yaklaşımların kullanılması önemlidir. Etkili İşbirliği ve İletişim Sorun çözme becerisinin benimsenmesi, etkili işbirliği ve iletişim ihtiyacını ortaya koyar. Farklı disiplinlerdeki zorlukların üstesinden gelmek için takım çalışması ve açık iletişim önem taşır. Esneklik ve Uyum Kabiliyeti Sorun çözme odaklı zihniyet, öğrencilere esneklik ve uyum yetisi kazandırır. Bu özellikler, farklı akademik disiplinlerde karşılaşılan zorluklarla baş etme becerisini artırır. Sonuç olarak, sorun çözme odaklı bir zihniyet benimsemek, çeşitli akademik disiplinlerde karşılaşılan zorlukların üstesinden gelmek için önemli bir adımdır. Bu zihniyet, analitik düşünce, yaratıcılık, işbirliği ve esneklik gibi becerilerin geliştirilmesine olanak tanır. Bu sayede, öğrenciler başarılı çalışmalar yürütebilir ve alanlarında öncü olabilirler.

What are the key elements of Einstein's problem-solving philosophy, and how can they be applied in contemporary academic research?

**Einstein's Problem-Solving Philosophy** Einstein's problem-solving philosophy entails three crucial elements: a sense of curiosity, development of thought experiments, and engagement with the scientific community. The integration of these components in contemporary academic research can yield significant advancements and insights. **Curiosity-Driven Approach** Firstly, fostering a sense of curiosity is pivotal to Einstein's problem-solving approach. For Einstein, the desire to comprehend the natural world and unveil its underlying principles was a driving force behind his scientific inquiries. In the present academic landscape, embracing this spirit of curiosity encourages researchers to push boundaries, ask thought-provoking questions, and seek novel perspectives that enable breakthrough discoveries. **Thought Experiments** Secondly, Einstein emphasized the use of thought experiments, or Gedankenexperimente, to mentally simulate the implications of hypotheses and assumptions. This practice helps researchers to examine hypothetical scenarios, discern flaws in their underlying logic, and refine their approach accordingly. For example, imagine a researcher examining the impact of a stimulus on a group of individuals. By contemplating how different stimulus levels might exaggerate or negate the reaction, the researcher can craft a more robust experimental design. Thus, thought experiments provide a valuable tool for enhancing the soundness and intellectual merit of contemporary academic research. **Engagement with the Scientific Community** Lastly, Einstein's problem-solving philosophy highlights the importance of engaging with a diverse and intellectually rigorous scientific community. Einstein relied on the exchange of ideas, debate, and collaboration with other scientists to refine his theories and challenge prevailing paradigms. In the context of modern academic research, researchers can apply this principle by actively participating in conferences, workshops, and collaborative projects that stimulate cross-disciplinary discourse and foster innovative thinking. **Conclusion** In conclusion, Einstein's problem-solving philosophy - defined by curiosity, thought experiments, and engagement with the scientific community - can provide a robust foundation for optimizing contemporary academic research endeavors. By adopting these core components, researchers can stimulate innovation, refine their methodology, and facilitate advancements in the pursuit of knowledge.

How does incorporating the problem-solving way of thinking, as exemplified by Einstein, enhance the process of addressing and navigating complex issues in various fields of study?

Embracing Einstein's Approach Incorporating the problem-solving perspective, which Einstein famously exemplified, offers significant benefits when addressing and navigating multifaceted issues spanning diverse fields of study. Einstein's method focuses on understanding the root of a problem, breaking it down into manageable components, and testing hypotheses through experimentation. Adopting this mindset enables individuals to better comprehend and manage intricate problems, leading to innovative and adaptable solutions. Critical Analysis of Issues A vital aspect of Einstein's approach lies in his reliance on critical analysis. He believed that the key to tackling difficult problems is to think deeply about the fundamental principles involved. By emphasizing such analysis, students and professionals alike can develop a solid conceptual foundation. This understanding allows for more effective communication, as individuals can address underlying key factors contributing to a situation or problem. Breaking Down Complexities Another element of Einstein's method involves breaking down complex problems into smaller, manageable parts. This technique encourages focusing on each subproblem individually, simplifying the task and promoting a sense of cognitive clarity. Consequently, abstract issues become increasingly tangible, which facilitates informed decision-making based on clear evidence, rather than relying on intuition or guesswork. Experimentation and Hypothesis Testing Einstein's commitment to experimentation and hypothesis testing is essential. These processes can provide tangible evidence to support or refute an idea, thereby strengthening the basis for decision-making. The ability to test ideas methodically ensures that solutions are both creative and empirically grounded. This approach also fosters a culture of continuous learning, as individuals can learn from errors or misconceptions to refine their understanding of complex issues. Applicability in Various Fields The versatility of the problem-solving approach makes it well-suited for application across diverse areas of study. From science and engineering to business and social sciences, the skills developed through Einstein's methods enhance practitioners' abilities to analyze and navigate intricate problems. This promotes innovative thinking, heightens adaptability, and ultimately leads to more sustainable and effective solutions. In conclusion, integrating Einstein's problem-solving way of thinking into various fields of study enriches the process of addressing and navigating complex issues. This approach emphasizes critical analysis, simplification of complexities, and experimentation, improving decision-making and fostering learning. By cultivating such skills, professionals and students can develop innovative, adaptable solutions to the multifaceted challenges that arise across disciplines.

In light of Einstein's famous quote on problem-solving and thinking differently, what strategies can be employed to foster a more innovative and effective approach to tackling academic challenges?

**Einstein's Insight on Problem-Solving** Einstein's renowned quote, 'We cannot solve our problems with the same thinking we used when we created them,' suggests a strong need for adopting novel and innovative approaches to address academic challenges. A shift in mindset is crucial to overcoming obstacles and generating original solutions. **Encourage Creative Thinking** One strategy to cultivate innovation comprises fostering a learning environment that encourages creative thinking. By offering opportunities for brainstorming, active discussion, and open-minded questioning, educators can stimulate students to think differently and collaboratively, producing new insights and ideas. **Embrace Diverse Perspectives** Incorporating diverse perspectives is vital to cultivating an effective approach. By bringing together students from differing backgrounds, experiences, and cultures, inventive ideas can emerge. This fusion of viewpoints can spark fresh ideas and challenge established beliefs, promoting innovation. **Promote a Growth Mindset** Adopting a growth mindset is another essential strategy for tackling academic challenges. By emphasizing the importance of grit, perseverance, and flexibility, students become inspired to address problems from different angles, rather than giving up at the first sign of difficulty. With this mindset, failure is perceived as an opportunity for learning and growth, thereby fostering a generation of resilient, innovative problem-solvers. **Integrate Cross-disciplinary Approaches** Lastly, integrating cross-disciplinary approaches to problem-solving can result in more effective innovations. By combining techniques and knowledge from different fields, unexpected solutions may arise. The synthesis of ideas from various academic areas can provide an enriched perspective, fortifying a student's ability to tackle complex challenges. In conclusion, fostering innovation to tackle academic challenges must involve nurturing creative thinking, embracing diverse perspectives, adopting a growth mindset, and integrating cross-disciplinary approaches. By nurturing these qualities, we can instill a sense of curiosity, resilience, and adaptability in students, empowering them to approach challenges with fresh thinking, as Einstein advocated.

What are the primary characteristics of a problem-solving way of thinking, and how can this mindset be cultivated within academic fields?

Key Characteristics of Problem-Solving Thinking The primary characteristics of a problem-solving way of thinking include analytical skills, critical thinking, creativity, adaptability, and perseverance. These traits facilitate the identification and analysis of issues, the generation of innovative solutions, and the tenacious pursuit of success despite challenges. Developing Analytical Skills and Critical Thinking One crucial aspect of cultivating a problem-solving mindset is developing analytical skills and critical thinking. This includes evaluating information with a discerning eye, recognizing patterns and trends, and taking a systematic approach to solving problems. Students can improve these skills by engaging in debates, workshops, and discussions that require them to scrutinize complex and ambiguous concepts. Encouraging Creativity Another important element in fostering a problem-solving mindset is encouraging creativity. Students should be allowed to experiment with various strategies and ideas to find unique, innovative ways to address challenges. By providing a supportive environment where risk-taking and failures are accepted as valuable learning opportunities, educational institutions can help students build the confidence that enables successful problem-solving. Promoting Adaptability Problem-solvers must also possess adaptability, enabling the ability to acknowledge when an approach is ineffective and to revise strategies accordingly. Faculty can help nurture this skill by assigning projects that require flexibility and dynamism, such as interdisciplinary studies, group work, or assignments involving real-world situations that present unanticipated complications. Cultivating Perseverance Lastly, perseverance is a key ingredient to a problem-solving mindset. This trait motivates individuals to pursue resolutions to issues relentlessly despite setbacks and difficulties. Educators can instill this characteristic by providing a challenging academic environment where resilience is necessitated in overcoming obstacles. Integrating Problem-Solving into Academic Fields To successfully cultivate a problem-solving mindset within academic fields, educational institutions must incorporate these key characteristics into their curricula and teaching methodologies. By offering opportunities for the development of analytical skills, critical thinking, creativity, adaptability, and perseverance, academic institutions create well-rounded, capable problem-solvers that thrive in any context.

How does Einstein's perspective on problem-solving and the necessity of distinct thinking approaches contribute to our understanding of complex issues across various disciplines?

Einstein's Perspective on Problem-Solving Einstein's perspective on problem-solving involves approaching challenges with creativity and flexibility, emphasizing the importance of distinct thinking methods. This view is instrumental in helping us understand and navigate complex issues across diverse fields. Necessity of Distinct Thinking Approaches Einstein's perspective on problem-solving highlights the need for different thinking approaches to tackle complex issues, leading to better outcomes. By encouraging us to think beyond conventional wisdom, it contributes significantly to our ability to solve problems in various disciplines. Cross-Disciplinary Applications Einstein's ideas can be applied to multiple disciplines, giving them the flexibility to address complex issues by adopting innovative thinking processes. For example, in science, these principles can help us break through barriers, develop new technologies, and propel research forward. In the realm of economics, they can foster creative solutions to financial challenges or resource scarcity. Furthermore, in social science, they can lead to better understanding and resolution of societal conflicts. Promoting Critical Thinking Einstein's perspective on problem-solving promotes critical thinking and the development of analytical skills needed to grasp complex concepts. This emphasis on critical thinking is vital to mastering multidimensional issues faced in diverse fields. It inspires curiosity, fostering a spirit of inquiry and encouraging individuals to probe deeper into topics, leading to a more in-depth understanding of the subject matter. Encouraging Collaboration Using distinct thinking approaches also necessitates collaboration, as it encourages experts from different fields to work together towards solving complex problems. Einstein's perspective supports interdisciplinary collaboration, which combines insights from various subject areas, leading to more comprehensive solutions. In conclusion, Einstein's perspective on problem-solving and the need for distinct thinking approaches significantly contribute to our understanding of complex issues across various disciplines. By promoting flexibility, creativity, critical thinking, and collaboration, it creates space for us to develop innovative solutions to the challenges faced in today's rapidly evolving world.

In the context of Einstein's problem-solving philosophies, how can researchers and academics create an environment conducive to fostering innovative solutions and novel approaches?

Embracing Curiosity and Open-mindedness In line with Einstein's problem-solving philosophies, researchers and academics can foster an environment conducive to innovative solutions by embracing curiosity and promoting open-mindedness. Einstein believed that curiosity driven investigations led to great achievements, stating that 'the important thing is not to stop questioning.' Therefore, cultivating an atmosphere where questions are encouraged, welcomed, and valued can empower individuals to challenge conventional wisdom and search for novel approaches. Adopting a Multidisciplinary Approach To foster innovation within academia's confines, it is essential to promote cross-disciplinary collaborations and non-linear thinking. Einstein's success in understanding the universe's complexities hinged on his ability to draw from various disciplines, merging physics, mathematics, and philosophy. By encouraging researchers to adopt a multidisciplinary approach, academics can higher the probability of transcending traditional boundaries and igniting the intellectual curiosity needed for groundbreaking discoveries. Creating a Supportive Community Developing a community that supports and nurtures creative thinking is crucial to cultivating innovative environments. Einstein famously said, 'Anyone who has never made a mistake has never tried anything new.' As such, researchers and academics must create spaces where individuals can take risks without fear of failure, knowing that their peers and mentors are behind them. Recognizing that failures can lead to valuable learning experiences, such environments can foster a growth mindset and resilience, truly enabling novel ideas to flourish. Prioritizing Diversity and Inclusivity Lastly, nurturing a culture of inclusivity and diversity is paramount to generating innovative solutions. As Einstein emphasized, 'we cannot solve our problems with the same thinking we used when we created them.' By embracing individuals from diverse backgrounds and perspectives, academia can overcome the limitations of insular thinking and access a rich array of ideas, contributing to the generation of pioneering concepts and approaches. In conclusion, fostering innovative solutions and novel approaches within academia aligned with Einstein's problem-solving philosophies involves encouraging curiosity, adopting multidisciplinary thinking, creating supportive communities, and prioritizing diversity and inclusivity. Through these principles, researchers and academics can create environments that spur groundbreaking discoveries, thus advancing human knowledge and understanding.

What are the core principles of a problem-solving way of thinking, and how can they be implemented in academic research methodologies?

Core Principles of Problem-Solving Thinking The core principles of a problem-solving way of thinking encompass understanding the problem, devising a plan, implementing the solution, and evaluating the results. Integrating these principles into academic research methodologies enhances the research process by promoting clarity, offering direction, and enabling researchers to ensure the validity of their findings. Understanding the Problem In academic research, understanding the problem involves clearly defining the research question or hypothesis, specifying the objectives, and identifying the desired outcomes. This step is crucial as it allows researchers to gain a comprehensive understanding of the issue at hand, enabling them to make well-informed decisions throughout the research process. Devising a Plan Devising a plan requires the researcher to outline a systematic approach to collecting and analyzing data. They must decide on the research design, select appropriate data collection methods, and establish the sampling technique. By creating a detailed and structured plan, researchers ensure that they are equipped to address the research question effectively. Implementing the Solution Carrying out the planned research activities is crucial for generating empirical evidence to support or refute the research hypothesis. This phase involves data collection, data analysis, and interpretation of results. Researchers must adhere to ethical guidelines and maintain objectivity, ensuring the validity and reliability of their findings. Evaluating the Results The final step in the problem-solving way of thinking is evaluating the results. Researchers must draw conclusions based on the findings, discuss the implications of the results, and consider limitations and potential areas for further inquiry. This process allows researchers to assess the impact of their work and identify possible improvements for future iterations of their research. Implementing Problem-Solving Thinking in Academic Research Incorporating problem-solving thinking into academic research methodologies bolsters the quality of research by providing a structured, systematic, and ethical approach to addressing complex issues. By fostering a deeper understanding of the problem, devising a solid plan, implementing the solution, and evaluating the results, researchers can cultivate a rigorous and robust research process.

How did Einstein's perspective on problem-solving influence the development of his groundbreaking theories, and what insights can be gleaned for contemporary researchers?

Einstein's Problem-Solving Process Albert Einstein's innovative problem-solving approach played a pivotal role in shaping his groundbreaking theories, which subsequently transformed the landscape of modern physics. His exceptional methodology offers valuable insights for contemporary researchers, encouraging them to think beyond the conventional boundaries and embrace the power of imagination. Embracing Thought Experiments Remarkably, Einstein relied on thought experiments, where he envisioned hypothetical situations that helped him develop an intuitive understanding of abstract concepts. These mental explorations allowed him to refine his ideas before undertaking a mathematical formulation, as seen in his development of the General Theory of Relativity. Carrying out such thought experiments, contemporary researchers can stimulate creativity and gain new insights into complex issues. The Role of Intuition Einstein strongly believed in the power of intuition, which guided him in formulating and testing his theories. He once stated, 'There is no logical way to the discovery of the essential nature of the world. There is only the way of intuition.' This emphasis on intuitive thinking encourages contemporary researchers to trust their instincts and engage in hunch-driven exploration, which leads to groundbreaking discoveries. Overcoming Preconceived Notions A significant aspect of Einstein's problem-solving approach was his ability to question and dismantle pre-existing beliefs about the physical world. He challenged the long-held assumption that space and time were fixed entities, proposing the radical idea of space-time curvature in his General Theory of Relativity. Such tenacity in questioning established norms provides a valuable lesson for contemporary researchers to challenge the status quo and seek scientific advancement. Adopting an Interdisciplinary Approach Einstein's remarkable range of interests spanned across diverse fields, including philosophy, politics, and music. His exposure to different disciplines allowed him to synthesize ideas and view problems from multiple perspectives, contributing to his scientific breakthroughs. Contemporary researchers can benefit from adopting an interdisciplinary approach to problem-solving, fostering innovative thinking patterns and tapping into previously untapped sources of knowledge. In conclusion, Einstein's problem-solving approach embodies the essence of innovative thinking within the scientific realm. By embracing thought experiments, valuing intuition, questioning pre-existing beliefs, and fostering interdisciplinary thinking, contemporary researchers can make significant strides in their quest for knowledge and the development of novel theories.

In the context of Einstein's belief that we cannot solve problems with the same thinking that created them, what are some strategies for cultivating a transformative mindset in academic research and problem-solving?

Redefining the Inquiry Process One crucial strategy for cultivating a transformative mindset in academic research and problem-solving is redefining the inquiry process. Researchers ought to employ intellectual curiosity and reflexivity in order to question pre-existing assumptions, design innovative research questions, and pursue alternative research methods. This allows scholars to critically evaluate their own work, as well as that of others, creating more effective and inclusive academic practices. Embracing Interdisciplinarity Another essential approach to fostering transformative thinking in academia is embracing interdisciplinarity. By actively seeking connections and collaborations across various disciplines, researchers gain a broader contextual understanding of their subject matter. Drawing on insights and methodologies from multiple fields exposes academics to diverse perspectives, fostering creative and innovative solutions to critical problems. Encouraging Divergent Thinking Promoting divergent thinking is an essential step for cultivating a transformative mindset. Divergent thinking involves considering multiple possibilities and solutions to complex issues simultaneously. Encouraging this approach in academic research and problem-solving fosters a willingness to take risks, tolerate ambiguity, and tolerate uncertainty. Developing these individual attributes is essential for approaching challenges with an open mind, embracing novel ideas, and transcending traditional thought paradigms. Contextualizing Knowledge Production To cultivate a transformative mindset, academics must recognize the need for contextualizing knowledge production. Acknowledging the social, political, and historical contexts within which research is conducted enables researchers to challenge dominant paradigms and open doors for alternative interpretations. Additionally, contextualizing knowledge production contributes to tackling global issues by foregrounding the role of diverse thinkers and their respective cultural contributions. Adopting an Experiential Learning Approach Lastly, adopting an experiential learning approach in academic research and problem-solving is crucial for fostering transformative mentalities. Experiential learning emphasizes direct, hands-on experiences and practical applications, allowing researchers to challenge their worldviews and foster personal growth. Implementing this strategy enables individuals to actively build, evaluate and modify their assumptions and beliefs, leading to transformative learning experiences. In conclusion, cultivating a transformative mindset in academic research and problem-solving requires multiple shifts in thinking and practice. By redefining the inquiry process, embracing interdisciplinarity, encouraging divergent thinking, contextualizing knowledge production, and adopting an experiential learning approach, researchers can transcend traditional thought patterns and create innovative solutions that align with Einstein's belief in thinking differently to solve complex problems.

What are the five ways of developing problem-solving skills?

Developing Deep Understanding The development of problem-solving skills starts by having a deep understanding of a problem. This involves identifying the problem and considering its root causes. Use critical thinking skills to dissect complex problems. Consider assumptions, evaluate arguments, and understand logical connections between ideas. Practicing Diligence Secondly, practice diligence in addressing problems. Patience and perseverance play vital roles in problem-solving. The willingness to revise and refine your work significantly improves problem-solving skills. Effort could make the difference between successful conclusions and incomplete solutions. Adopting a Systematic Approach Thirdly, adopt a systematic approach when solving problems. Systems help to create order and structure. They support the meticulous examination of different solutions and their impacts. It is essential to explore all possible solutions while designing optimum outcomes. Incorporating Creative Thinking Fourthly, incorporate creative thinking into your problem-solving toolkit. Unconventional thinking opens the door to innovative solutions. It facilitates the brainstorming process, generating novel ideas and abstract concepts. Remember: thinking outside the box often uncovers optimal solutions. Learning from Mistakes Lastly, embrace mistakes as learning opportunities. Reflect upon failures and strive to understand what went wrong. This process enhances decision-making abilities, enriches knowledge, and builds resilience. Continuous learning remains vital for improving problem-solving skills. In closing, developing problem-solving skills involves deep understanding, practicing diligence, adopting a systematic approach, incorporating creative thinking, and learning from mistakes. These strategies foster resilience, innovation, and efficiency in problem-solving.

Did Einstein say we can't solve problems by using the same kind of thinking we used when we created them?

Interpreting Einstein's View A widely attributed quote to Einstein says that we cannot solve problems by using the same kind of thinking we used when we created them. However, despite its popularity, no documented evidence exists that the scientist actually verbalized or wrote this statement. Examining Its Authenticity While numerous online platforms and motivational speakers commonly attribute this quote to Einstein, no primary sources corroborate its authenticity. Several quote databases and collections of Einstein’s writings and speeches do not include this sentence. Possible Misinterpretation It is plausible that the statement is a misinterpretation or a paraphrase of Einstein’s actual beliefs. Einstein did emphasize the importance of innovative thinking and radical approaches to scientific breakthroughs in numerous instances throughout his career. Exploration of Similar Quotes Quotations with similar sentiments can be found in Einstein’s documented statements. For example, he once said, 'The true sign of intelligence is not knowledge but imagination.' This quote reflects the same underlying principle of seeking novel approaches to problems. Conclusion: Einsteins Perspective In conclusion, while Einstein might not have said the exact words, it is clear that he advocated for innovative thinking to solve complex problems. By embracing change and fostering curiosity, we can challenge pre-existing systems and ideologies to create effective solutions.

What are the thinking and problem-solving skills?

Understanding Thinking and Problem-Solving Skills Thinking skills denote our mental abilities to reason, make decisions, and create fresh ideas. Critical thinking involves analysing and critically evaluating information while creative thinking refers to generating innovative solutions. Role of Creative Thinking Creative thinking employs our imagination to formulate new concepts. It's pivotal in designing unique solutions to complex problems. These skills aid us in perceiving situations from varied perspectives and exploring innovative approaches. Importance of Critical Thinking Critical thinking is the process of systematically analyzing a complex situation by pinpointing assumptions, evaluating arguments, and drawing conclusions. It helps us understand the conceptual framework of an issue and draw reasoned conclusions about it. It's crucial in making informed decisions in daily life. Problem-Solving Skills Defined Problem-solving skills are a range of different skills that help us solve problems or challenge. These may include analytical thinking, communication skills, creativity, research, and decision-making abilities. They help us break down problems into smaller, more manageable parts. Value of Problem-Solving Skills Effective problem-solving implies recognizing a problem, understanding the nature of the problem, exploring possible solutions, implementing a solution, and reviewing the results. These skills are crucial in all aspects of life, from personal issues to professional tasks. In conclusion, thinking and problem-solving skills are integral to our daily interactions and decision-making processes. Developing these skills equips us to navigate complex situations and propose effective solutions. Therefore, they are highly valued in academic, personal and professional domains.

Yu Payne is an American professional who believes in personal growth. After studying The Art & Science of Transformational from Erickson College, she continuously seeks out new trainings to improve herself. She has been producing content for the IIENSTITU Blog since 2021. Her work has been featured on various platforms, including but not limited to: ThriveGlobal, TinyBuddha, and Addicted2Success. Yu aspires to help others reach their full potential and live their best lives.

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Einstein’s ‘Imaginary Elevator’ Thought Experiment Proven Right Again

Well, Einstein’s done it again!

That is to say, the gravitational theories of Albert Einstein have once again been confirmed, and to a new degree of precision. The equations of general relativity predicted a certain quantity would be zero, and physicists at the National Institute of Standards and Technology (NIST) have calculated a record-low, unbelievably tiny result — basically, as good to zero as we can get.

So what did they measure? The variation between different ultra-precise atomic clocks around the world as it orbited the sun. It’s … a bigger deal than it sounds like.

Elevator Action

Part of Einstein’s genius was his ability to think things through using just his imagination. These so-called  gedankenexperiments  (“thought experiments”) yielded many of his insights in formulating the theory of general relativity, which focuses on gravity’s effects.

Among the more famous examples is one focusing on an  imaginary elevator . Someone inside would be unable to distinguish a gravitational field from acceleration — the downward pressure you normally feel from Earth pulling at you could just as easily be the elevator accelerating ‘upward’ toward you in zero gravity. Stuck inside the elevator, with no windows, you couldn’t tell the difference.

The NIST team tested another aspect of the thought experiment, which says that everything inside the elevator would feel the same accelerations, and their relative properties would remain constant — zero change. It’s an idea called local position invariance (LPI). They used Earth itself as the elevator, and compared the “ticks” of a dozen atomic clocks all over the planet. After studying nearly 15 years’ worth of data the results were in: the difference was just 0.00000022 plus or minus 0.00000025. Pretty close to zero!

The results  appeared today in  Nature Physics .

Like Clockwork

It’s closer to zero than we’ve ever gotten before, thanks to improved tech, particularly the incredible accuracy of today’s atomic clocks, “so stable that they could be in error by no more than a thousand seconds over the life of our universe, ~14 billion years,” according to the paper.

Unfortunately, it’s also about as close as scientists can come with those clocks too — but new atomic clocks are already in the works and should provide even finer measurements in years to come.

But why bother, when we’re already so close to zero? Well, this isn’t just about NIST showing off. Because LPI should be a fundamental property of the universe, it’s part of the calculation of some of nature’s other fundamental values, such as the mass of certain particles. Having an improved figure for LPI means better numbers for everything else.

Plus, of course, confirming once again that, yep, ol’ Einstein really knew what he was talking about. Not that it’ll stop scientists from  trying to find out otherwise .

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Learn How to Think Like Einstein

Albert Einstein is widely considered one of the smartest people who ever lived, significantly impacting our understanding of the world around us. His General Theory of Relativity has redefined what we know about space and time and is one of the pillars of modern physics. What’s also remarkable about Einstein’s achievements is that they relied largely on his mental powers and the intricacy of his imagination. He was able to discern and relate very complex scientific concepts to everyday situations. His thought experiments, that he called Gedankenexperiments in German, used conceptual and not actual experiments to come up with groundbreaking theories.

CHASING A BEAM OF LIGHT

One of Einstein’s most famous thought experiments took place in 1895, when he was just 16. The idea came to him when he ran away from a school he hated in Germany and enrolled in an avant-garde Swiss school in the town of Aarau that was rooted in the educational philosophy of Johann Heinrich Pestalozzi, which encouraged visualizing concepts.

Einstein called this thought experiment the “ germ of the special relativity theory. ” What he imagined is this scenario – you are in a vacuum, pursuing a beam of light at the speed of light – basically going as fast as light. In that situation, Einstein thought, that light should appear stationary or frozen, since both you and the light would be going at the same speed. But this was not possible in direct observation or under Maxwell’s equations,  the fundamental mathematics that described what was known at the time about the workings of electromagnetism and light. The equations said that nothing could stand still in the situation Einstein envisioned and would have to move at the speed of light – 186,000 miles per second.

Artists pose in a laser projection entitled ‘Speed of Light’ at the Bargehouse on March 30, 2010 in London, England.  (Photo by Peter Macdiarmid/Getty Images)

Here’s how Einstein expanded on this in his Autobiographical Notes :

“If I pursue a beam of light  with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as an electromagnetic field at rest though spatially oscillating. There seems to be no such thing, however, neither on the basis of experience nor according to Maxwell’s equations. From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest. For how should the first observer know or be able to determine, that he is in a state of fast uniform motion? One sees in this paradox the germ of the special relativity theory is already contained.”

The tension between what he conceived of in his mind and the equations bothered Einstein for close to a decade and led to further advancements in his thinking.

LIGHTNING STRIKING A MOVING TRAIN

A 1905 thought experiment laid another cornerstone in Einstein’s special theory of relativity. What if you were standing on a train, he thought, and your friend was at the same time standing outside the train on an embankment, just watching it go by. If at that moment, lightning struck both ends of the train, it would look to your friend that it struck both of them at the same time.

But as you are standing on the train, the lighting that the train is moving towards would be closer to you. So you would see that one first. It is, in other words, possible for one observer to see two events happening at once and for another to see them happening at different times.

“Events that are simultaneous with reference to the embankment are not simultaneous with respect to the train,” wrote Einstein. 

The contradiction between how time moves differently for people in relative motion, contributed to Einstein’s realization that time and space are relative.

Lightning strikes during a thunderstorm on July 6, 2015 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

MAN IN FALLING ELEVATOR

Another thought experiment led to the development of Einstein’s General Theory of Relativity by showing that gravity can affect time and space. Here’s how he described it happened:

“I was sitting in a chair in the patent office at Bern when all of a sudden a thought occurred to me,” he remembered. “If a person falls freely, he will not feel his own weight.” He later called it “the happiest thought in my life.”

A 1907 thought experiment expanded on this idea. If a person was inside an elevator-like “chamber” with no windows, it would not be possible for that person to know whether he or she was falling or pulled upward at an accelerated rate. Gravity and acceleration would produce similar effects and must have the same cause, proposed Einstein. 

“The effects we ascribe to gravity and the effects we ascribe to acceleration are both produced by one and the same structure,” wrote Einstein.

One consequence of this idea is that gravity should be able to bend a beam of light – a theory confirmed by a 1919 observation by the British astronomer Arthur Eddington. He measured how a star’s light was bend by the sun’s gravitational field.

THE CLOCK PARADOX AND THE TWIN PARADOX

In 1905, Einstein thought – what if you had two clocks that were brought together and synchronized. Then one of them was moved away and later brought back. The traveling clock would now lag behind the clock that went nowhere, exhibiting evidence of time dilation – a key concept of the theory of relativity.

“ If at the points A and B of K there are clocks at rest which, considered from the system at rest, are running synchronously, and if the clock at A is moved with the velocity v along the line connecting B, then upon arrival of this clock at B the two clocks no longer synchronize but the clock that moved from A to B lags behind the other which has remained at B,“ wrote Einstein. 

This idea was expanded upon to human observers in 1911 in a follow-up thought experiment by the French physicist Paul Langevin. He imagined two twin brothers – one traveling to space while his twin stays on Earth. Upon return, the spacefaring brother finds that the one who stayed behind actually aged quite a bit more than he did.

Einstein solved the clocks paradox by considering acceleration and deceleration effects and the impact of gravity as causes of the for the loss of synchronicity in the clocks. The same explanation stands for the differences in the aging of the twins.

Time dilation has been abundantly demonstrated in atomic clocks, when one of them was sent on a space trip or by comparing clocks on the space shuttle that ran slower than reference clocks on Earth.

How can you utilize Einstein’s approach to thinking in your own life? For one – allow yourself time for introspection and meditation. It’s equally important to be open to insight wherever or whenever it might come. Many of Einstein’s key ideas occurred to him while he was working in a boring job at the patent office. The elegance and the scientific impact of the scenarios he proposed also show the importance of imagination not just in creative pursuits but in endeavors requiring the utmost rationality. By precisely yet inventively formulating the questions within the situations he conjured up, the man who once said “imagination is more important than knowledge” laid the groundwork for the emergence of brilliant solutions, even if it would come as a result of confronting paradoxes.

Competitions

“the einstein technique” of creative thinking for writers.

By Ken Miyamoto · June 26, 2020

How can screenwriters use Albert Einstein’s creative thinking technique — combinatory play — to better the development and writing of their screenplays?

Albert Einstein (March 14, 1879 – April 18, 1955) was one of the most brilliant minds that our world has seen. The famous theoretical physicist developed the theory of relativity and is considered to be the father of modern physics.

Because of his brilliance, many sought his outlook and perspective on many topics beyond science.

In 1945, a French mathematician was trying to understand the thinking patterns of famous and brilliant scientists. Einstein wrote a letter in response in which he stated:

“The words or the language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The psychical entities which seem to serve as elements in thought are certain signs and more or less clear images which can be ‘voluntarily’ reproduced and combined. It is also clear that the desire to arrive finally at logically connected concepts is the emotional basis of this rather vague play with the above-mentioned elements. But taken from a psychological viewpoint, this combinatory play seems to be the essential feature in productive thought — before there is any connection with logical construction in words or other kinds of signs which can be communicated to others.”

Einstein utilized a specific thought process — combinatory play — which would later become known as “The Einstein Technique” of creative thinking.

In Seeing What Others Don’t: The Remarkable Ways We Gain Insights ,  researcher Gary Klein wrote:

“At the age of sixteen, Einstein began to conduct thought experiments about beams of light. These thought experiments were mental exercises that helped Einstein appreciate properties of light and also helped him notice anomalies and inconsistencies. Einstein imagined different conditions and possibilities, pursuing these speculations for ten years.”

In his book  Sparks of Genius , researcher Robert Root-Bernstein explains:

“The young Einstein was thoroughly schooled in what modern scientists would call ‘thought experiments’: seeing and feeling a physical situation almost tangibly, manipulating its elements, observing their changes — all of this imagined in the mind.”

Here we apply Einstein’s creative thinking technique with conceptualizing screenplays, using the three stages that Einstein himself used to solve problems create concepts to explore.

1. Consciously Build a Mental Model of How Your Story Works

Visualization is a crucial part of the writing process, especially in screenwriting. You’re writing within a visual medium so it’s key to visualize your concepts, stories, settings, and characters first before you even come close to attempting to type them out.

So visualize as much of your cinematic story as you can. It may take days, weeks, and months to do so, but it’s worth it. Play it over and over in your head as you build on each visual, moment, and scene.

Start by visualizing the trailer of your movie. Then add a bit more to those beats to create a visual beginning, middle, and end.

2. Test Your Story in Your Mind By Mentally Stimulating Different Scenarios

The biggest mistake writers make is following their very first ideas. Einstein would test his ideas and models for an extended period of time before even coming close to any conclusions, theories, or discoveries.

Try to visualize different scenarios and outcomes within the story model that you’ve initially envisioned. Play with it. Visualize different results. Visualize what happens when your characters make different decisions.

You can even take the core concept and place it into different genres and envision how that concept would work as a comedy, science fiction piece, horror movie, action flick, or drama.

3. Test the Story in the Real World

Scientists would experiment in real life. Automakers would take a concept car and put it through multiple tests. Film editors and directors would take an edit of a film and screen it for test audiences or executives.

As a screenwriter, you can take selected versions of your story that you’ve been playing with in your head and share it with a trusted peer or mentor.

Or you can test it in the real world by starting the script and seeing how it pans out. If you don’t want to commit that visual play to a full script, you can write a synopsis or treatment to flesh it out even more.

If it doesn’t work, you can simply repeat the first two steps until you find what does work.

The Einstein Technique is simple. It centers on visualization. And like any great scientist, you can visually experiment by adding or subtracting different elements while envisioning the different outcomes.

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