What is the value of a thought experiment?

Thought experiments refer to experiments that are carried out using imagination and are experiments that cannot be done (or are not done in reality) in reality. For example, in Einstein's famous thought experiment on relative motion, and in Einstein's popular science book The Evolution of Physics, co-authored by Einstein and Infeld, there is an experiment that asks the reader to imagine a smooth, frictionless ground and sphere, but this is not possible in reality (or temporarily).

Thought experiments require imagination, not the senses. Albert Einstein once said:"The truth of the theory is in your mind, not in your eyes.

And in the midst of this. Most of Galileo's experiments were thought experiments, and history has proven that he did not throw two iron balls from the Leaning Tower of Pisa at the same time to prove Aristotle wrong. A thought experiment is a rational thinking activity that takes place in a person's mind.

This mental activity follows the format of an experiment, so it is also called"Experiments"。Today, with the increasing development of science, our cognitive activities are becoming more and more distant from daily intuitive experience and intuition, the instruments and equipment required for scientific research activities are becoming more and more purified and idealized, and physical and chemical experiments sometimes cannot meet the needs of scientific development, and the use of thought experiments to conduct scientific research has become an inevitability. Thought experiment is a set of pure and idealized instruments and equipment and research objects designed and constructed by scientists in their minds, and they carry out purely idealized experimental operation and control of it, so that certain factors related to the experimental object are expressed in the form of absolute simplification, purification, setting and limitation; Then, through the perception and description of this idealized object, the mental activity of discovering and obtaining scientific facts and natural laws.

Thought experiments were highly integrated and fully developed by Einstein, and are called thought experiments and ideal experiments. Later, it was called"Abstract experiments"、"Hypothetical thoughts"、"Thought experiments"with"Ideal for experiments"Wait a minute.

Thought experiments have been germinating since ancient times, and the ancient Greek scientist Archimedes always made a kind of thought when studying area and volume"Experiments"。"Imagine measuring the area of a flat object cut into a shape with a uniform material so that you can understand their relationship and then prove it mathematically. "In the 5th century B.C., Zeno used a thought experiment to demonstrate"Achille chasing turtles"、"The arrow does not move"and other propositions.

Thought experiments have also been done in China, in the ancient Zhuangzi's "Tianxia Chapter"."One foot of air, half of it is taken in a day, and it is inexhaustible"Such an example to demonstrate the infinite divisibility of matter. Thought experiments were originally developed mainly from physics, which is related to the fact that physics mainly began with the study of the motion of macroscopic objects, and most of Aristotle's research in physics was thought experiments.

In modern times, it has gradually transformed from a speculative form to a scientific thought experiment. Scientific thought experiments began with Galileo, and it can be said that the 17th century was the period of the origins of scientific thought experiments. In the modern scientific period, because scientific exploration is broader and deeper, thought experiments are more indispensable.

Experiments are one of the most basic methods of scientific understanding in natural science. Any actual experiment is a perceptual material activity, a perceptual cognitive activity. Scientists, instruments and equipment, objects of investigation, and environmental conditions are all perceptual existence and perceptual intuitive objects, which constitute the realistic scientific practice and cognitive system.

All physical and chemical experiments will be limited by subjective and objective conditions, as well as the operation of instruments and equipment, etc., therefore, the relevant factors of the object to be examined cannot be absolutely simplified.

The so-called thought experiment is to use one's own imagination to complete relevant academic experiments and complete academic verification, and there are similar thought experiments in history, such as Einstein's research on relative motion is a thought experiment, which cannot be done in reality, because there can be no smooth and frictionless plane. In quantum mechanics, what are the dry divisions of thought experiments?

Schrödinger's catSchrödinger's cat is a very important and classic thought experiment in history. The experimental process is to enclose a cat and some toxic and radioactive particles in a box with a cat, and within the closed time, the law of decay of radioactive elements is used to trigger the counter, so as to release toxic gases to kill the cat. Schrödinger believed that if the box was opened at a specific time, the cat would be in a state of life and death.

This experiment is actually a paradox in quantum mechanics.

Bell inequality Bell inequality is a mathematical inequality that is contrary to reality proposed by physicist Bell, this theorem is based on a strict restriction on the correlation of particle measurements, in quantum mechanics, the separation system needs to exist a certain degree and logic in the theory of localized reality, and Bell's inequality is the opposite, Bell inequality proposes that under this localized reality condition, quantum has uncertainty. Scientists then studied Bell's inequality and the theory of defining reality, and found that the theory in quantum mechanics was correct.

In quantum mechanics, the over-distance effect of quantum entanglement exists, in this experiment, a laser is used to segment a particle and turn it into an entangled photon pair, in the academic study of quantum entanglement, this state will destroy the balance of the quantum system, so the entangled photon pair will eventually disappear. Theoretically, this phenomenon is from a microscopic point of view, but from a macroscopic point of view, the existence of this phenomenon has not been verified. Therefore, the over-distance effect of quantum entanglement only exists in the microscopic theoretical world.

It's a simulation experiment in your head! For example, Stephen Hawking.

Although ideal experiments and thought experiments are both abstract thought experiments, they are different, and if the relationship between the two is confused, it will objectively inevitably lead to blindness in scientific research, make researchers at a loss, and even adversely affect the development of science and technology. In the history of science, there are many examples of indiscriminate between the two types of thought experiments. For example, in the case of superconductivity, it was generally believed that the phenomenon of zero resistance was an idealized state that could not be achieved before experiments.

To a certain extent, this understanding has affected the practical exploration of it. Another example is Albert Einstein.

And Infeld had conceived one"Single-lease reed electron diffraction"experiment, and considered it an ideal experiment, in fact impossible to realize, but this idea was later adopted by the Soviet Union.

Scientists have succeeded in doing this through physicochemical experiments. Ideal experiment refers to the idealization of the experimental object and the experimental process, and logical thinking.

with intuition, visual thinking.

Organic combination highlights the ideal state of things and conditions, but it does not exist in practice. This ideal state cannot be expressed in physicochemical experiments, and the results of ideal experiments are only approximate descriptions of the limits of objective facts.

An ideal experiment is not the same as an ideal model. An ideal model is a model that describes an ideal object through a high degree of abstraction. Many of the phenomena in the field of natural sciences are idealized objects, such as particles, absolute rigid bodies, absolute black bodies, ideal fluids, ideal solutions, etc., and these ideal object models can be returned to prototypes.

The ideal debris zone experiment eliminates the interference that cannot be excluded in the physicochemical experiment, and makes the research problem highly idealized. The results of an ideal experiment, while infinitely close to objective facts, can never be achieved in practice. Carnot Thermal Cycle Experiment, conceived by Albert Einstein"Twin Paradox Experiment"etc., are ideal experiments.

Thought experiments refer to experimental activities carried out in the mind through logical deduction under specific conditions, relying on scientific principles.

The essential precursor of the thought experiment lies in the fact that it is based on the theoretical principle of wisdom and liquidity, but it must also rely on empirical appearances, which connect with the objective world through concepts and logic, showing that it is mainly based on logical reasoning, but it also contains empirical content. Because it reveals access to natural information and leads people to new discoveries. Thought experiments are often seen as idealized products, such as discussing how something can move in a plane without friction, without the need for experimentation at all, because it only involves calculations.

Galileo once proposed:"No stupid experiments, I'm sure the result will happen the way I told you, because it has to happen that way. "Galileo means:

Thought experiments can produce a result that does not require materialization experiments. The famous French historian of science, Alexandre Kovaret, asks us to acknowledge the credit of Galileo for making us realize the use of thought experiments and thus saving us the trouble of doing actual experiments.

According to the format of the physicochemical experiment, the main process and results are presented in a logical form. Maher said"The basic square scrambling stare slip method of the thinking simulation experiment is the same as that of the physical experiment.

It is a specific scientific research method that is used when physical and chemical experiments cannot be carried out. Although the result is an unconfirmed understanding of slow waxing, it can be tested by scientific practice when the physical and chemical conditions are met. After Galileo repudiated Aristotle's law of falling bodies, Stavin conducted an experiment that confirmed this insight.

Stavin wrote:"The experiment against Aristotle is this: if we take two lead balls, one of which is ten times heavier than the other, and drop them from a height of thirty feet at the same time, and land them on a plank or something that makes a clear sound, then we see that the light lead ball does not take ten times as long as the heavy lead ball, but falls on the plank at the same time, so that the sound they make sounds like one sound.

The evaluation of thought experiments is to examine the consistency between thought experiments and objective facts, objective processes, and their laws. The evaluation of thought experiments is a complex process, which not only makes judgments on the attributes and functions of the experimental object through practice, but also confirms the real and objective needs through practice, so as to compare the performance of the object with the needs of the subject, and finally make a reasonable evaluation. In this process, the influence of subjective factors will be more permeated, such as individual differences, the background and culture of the times, people's emotions, emotions, etc., will affect the evaluation results to varying degrees.

The evaluation of thought experiments includes value evaluation and scientific evaluation.

The value evaluation of thought experiments should examine whether the value goals tended to by thought experiments conform to actual scientific needs, whether they meet the objective requirements of human development, and what kind of impact they have on the development of society. It is the process and result of people's conception of grasping the value of thought experiments, and the value of them. The value evaluation of thought experiments should be measured by a certain value scale.

Different historical periods have different value scales. The value standard of a thought experiment must be objective, and all subjective things, such as interests and hobbies, are not the value standard of a thought experiment.

The scientific evaluation of thought experiments is made by comparing the subjective understanding of the experimental subject with the objective facts. Only theories that truthfully reflect the objective changes and objective connections that occur within the object can obtain scientific evaluation. On the other hand, theories that cannot be consistent with objective facts, no matter how self-consistent and complete their experiments are, and how consistent their narratives are with life experience, cannot strictly say establish their scientific nature.

And those "thought experiments" that deliberately use false concepts and use some vague and ambiguous judgments in an attempt to evade testing and defuse counterexamples cannot be labeled as scientific because they do not even have the minimum testability. In a sense, a series of conclusions can be derived through thought experiments that can be finally observed.

Although the empirical and scientific evaluation of thought experiments is very complicated due to the particularity of the thought experiments themselves, for example, when the objective conditions do not meet the direct test, they can only be evaluated with the help of indirect tests, but when the conditions that can be directly tested are met, people prove the factual conclusions through observation or experiments, so as to prove the thought experiments. If "t" is used to represent the thought experiment, and "e" is used to represent the observable empirical statement contained in t, then the scientific evaluation mode of the thought experiment can be expressed as:

T may be true. t→e1，e2，……En has observed the ,...... of E1, E2en t is more likely to be true.

There are many aspects involved in evaluating the value and scientificity of thought experiments, but the most important evaluation is the scientific evaluation of thought experiments. Through the evaluation of thought experiments, the understanding and practice of thought experiments are given meaning, and human activities are guided and regulated to develop in a direction that is beneficial to human beings themselves.