The article is selected from:

Science and Culture Review No.2, 20 19, pp. 107- 1 19.

"Opposing Philosophy" is the title of a chapter in a book written by Steven Weinberg, a great contemporary physicist, winner of the Nobel Prize in Physics and founder of the "Standard Model" of elementary particle physics. Weinberg eloquently pointed out that philosophy does more harm than good to physics-although it may sometimes provide good insights, it is usually a tights that physicists must get rid of themselves. More radically, Stephen Hawking wrote a famous saying-"Philosophy is dead". His reason is that the big problems discussed by philosophers in the past are now taken over by physicists. Similar views are widely circulated among scientists, and scientists have made no secret of them. Neil de Grasse Tai Sen, a famous figure in American popular science circles, publicly declared in the same style: "... we know the expanding universe, ... we know quantum physics, ... each one is far beyond the range that the whole philosopher group can infer from sitting in a chair, ... (they) are out of date in essence."

I don't agree with these views. In this paper, I gave some refuting arguments. I will demonstrate that philosophy always plays an indispensable role in the development of science, especially in the development of physics. In addition, this situation is likely to continue.

This is a long-standing debate. There was an interesting scene in Athens in the classical period. At that time, all the young people in the golden age of this city were educated in famous schools. Among them, two schools stand out: Isocratus School and Academy established by Plato. The competition between the two schools is fierce, just like the competition between Cambridge and Oxford, but it's not just about quality: the education methods of the two schools are very different. Isokrates provides high-level practical education and teaches young people in Athens the skills and knowledge they need to become politicians, lawyers, judges and architects. On the other hand, the college focuses on discussing general questions about foundations: what is justice? What should be the best law? What is beauty? What is matter made of? Plato gave this way of asking questions a good name: philosophy.

The differences between the two schools are deeply rooted. Isocratus criticized Plato's direct access to education and knowledge;

Those who do philosophy, those who judge proofs and arguments ... are used to asking questions, but they never contribute to their actual duties ... Even if they happen to have the ability to control something, they will automatically destroy it, and those who have no knowledge of (philosophy) argumentation will actually do better if they are trained (in a specific science) and have a correct point of view. So philosophy is useless to science.

This is obviously similar to the view of contemporary scientists that philosophy has no effect on science.

As it happens, an excellent young student of Plato's Academy wrote an article in response to Aesop Crates' criticism. This is a famous article in ancient times-provocation. Only a part of it has survived, and this article can only be understood by reconstructing a large number of quotations from later generations. A group of classical scholars led by Doug Hutchinson and Monte Ransome Jonson recently completed a new reconstruction of it, and now it can be read online. The exhortation is probably written in the form of a dialogue between two people who defend two opposing positions. The existing part of the text is enough to make people understand the main arguments put forward by the young student in response to Aesop Kratos in order to defend philosophy.

The clever young man left Athens after writing this pamphlet, but he finally came back to start his own college and had a successful career. His name is Aristotle.

The development of science and philosophy in 2000 not only proved-more likely-but also strengthened Aristotle's defense against Aesop Crates' accusation that philosophy was useless. His argument still seems very pertinent now, and I am inspired by it to respond to these current assertions that philosophy is useless to physics.

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Aristotle's first argument comes from the fact that:

General theory can support and often contribute to the progress of practice.

I divide this matter into two aspects: one is the correlation between philosophy and science in the past; Second, whether philosophy today has nothing to do with science. Let's talk about the first point.

Today, 2000 has passed. During this period, both philosophy and science have made remarkable progress, and there are countless historical evidences of the influence of philosophy on science.

Here are some examples of astronomy and physics to illustrate this influence. Let me just give you a few examples. In ancient astronomy, we only know that the earth is round and its size, as well as the size of the sun and the moon, the distance from the earth to the sun and the moon, the movement of planets in the sky, and some foundations of modern astronomy and modern physics; And this ancient astronomy is the direct product of philosophy. The core issues that caused these progress were raised by Academy and Lv Keang, and they all came from theoretical rather than practical concerns. Although many centuries later, Galileo and Newton took a big step forward from the previous physics and astronomy, especially Aristotle's worldview, they still relied heavily on their previous achievements. Galileo and Newton expanded their previous knowledge, reinterpreted and reconstructed it, and established something new on this basis. Galileo's thoughts, in particular, would be unreasonable without Aristotle's physics.

More importantly, without Galileo's tracing back to Plato's thought, that is, his pursuit of the ideal mathematical order hidden behind the appearance, his work would be unreasonable. Galileo was guided by a fanatical Platonism. In his works, Newton also made it clear that many of his ideas borrowed from ancient philosophy, especially Democritus's concepts, such as empty space, atomism, natural linear motion, etc., which were originally derived from philosophical motives. In addition, his important exposition on the nature of time and space is based on his discussion and refutation with Descartes.

However, the direct influence of philosophy on physics is by no means limited to the period when modern physics was just born. This effect can be seen in every important step of progress. For example, in the 20th century, the two major advances in physics in the 20th century were strongly influenced by philosophy. If there is no philosophy about time, they will be unreasonable. Quantum mechanics originated from Heisenberg's intuition, which was rooted in the strong positivist philosophical atmosphere he felt at that time: only those observable things can people acquire knowledge. Heisenberg's groundbreaking paper 1925 clearly talks about this point:

The goal of this work is to lay a foundation for quantum mechanics theory based on the relationship between observable measurements in principle.

Similarly, it is obviously a philosophical attitude that led Einstein to discover the special theory of relativity: by limiting the scope to observable things, we realize that the concept of simultaneity is misleading. Einstein explicitly admitted that he referred to the philosophical works of Mach and Poincare. Without the input of these ideas, his special theory of relativity would be unreasonable. Although not from the same influence, Einstein's general theory of relativity is more influenced by philosophy. Once again, he explicitly admitted his reference to philosophy, this time from the critical thinking of Leibniz, Becquerel and Mach. The relationship between Einstein and philosophy is really complicated: for example, he admitted that Schopenhauer had a convincing influence on him. This is not obvious in his physics, but Schopenhauer's concepts of time and representation may not be difficult to identify from Einstein's thought of guiding general relativity; This effect has also been studied. Is it really a coincidence that the greatest physicist of the 20th century paid such obvious attention to philosophy when he was young-he read Kant's three criticisms when he was 15 years old?

Why are these effects? Because philosophy can provide new ideas, novel perspectives and critical thinking methods. Philosophers have the tools and skills needed by physics, but when training and cultivating physicists, these things are missing: concept analysis, attention to fuzziness, accuracy of expression, ability to find gaps in standard argumentation, creating new perspectives, finding weak links in concepts and finding alternative conceptual explanations. No one said it better than Einstein himself:

The knowledge of historical and philosophical background gives us independence from the prejudice that most scientists of our generation fall into. This independence brought by philosophical insights-in my opinion-is a sign that separates simple craftsmen or experts from those who really seek truth.

Sometimes, there is a stronger saying: "First of all, scientists can't do anything without the permission of philosophy."

Therefore, if we read what the greatest scientists such as Heisenberg, Schrodinger, Bohr and Einstein have said about the usefulness of philosophy, we will find that their views are completely opposite to those expressed by Hawking and Weinberg.

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The following is Aristotle's second argument:

People who deny the function of philosophy are also doing philosophy.

This is by no means so boring at first glance. Let's see what Weinberg and Hawking wrote. Both of them have made great scientific achievements. For example, Weinberg discovered the correct symmetric group describing the interaction between elementary particles, while Hawking discovered that black holes are hot and calculated their temperatures. When doing such a thing, they are doing science. When they write something like "philosophy is useless to physics" or "philosophy is dead", they are not doing physics. So what are they doing? They are thinking about the best way to develop science.

The problem here is scientific methodology. Of course, a central issue of philosophy of science is to ask questions carefully: how to do science and what will be more effective. Excellent scientists will reflect on their methodology, and Weinberg and Hawking have indeed done so, which is very good. But so what?

They expressed some concept about scientific methodology. This is the eternal truth about how science has always worked and how it should work. This is the best understanding of our existing science?

Neither. It is not difficult to trace the origin of this concept. It originated from the background of logical positivism and was revised by Popper and Kuhn. At present, the mainstream methodology in theoretical physics comes from the two concepts of falsifiability and scientific revolution, which are very popular among theoretical physicists. They are often mentioned and widely used to guide research direction and evaluate research work.

Therefore, when asserting that philosophy is useless, Weinberg, Hawking and other "anti-philosophy" scientists are actually paying tribute to some scientific philosophers, who have either read their works or absorbed their thoughts in their environment. This kind of marking is impossible to go wrong. When they regard philosophy as a bunch of false propositions-false propositions mean that the words that make up this proposition have no real meaning, and a bunch of things that are repeatedly ridiculed like Nell de glasser Tai Sen, these criticisms can be easily traced back to the anti-metaphysical position of the Vienna School. Behind these curses on philosophy, people can almost hear the slogan of Vienna School: "No metaphysics!" " "

Therefore, when Weinberg and Hawking claim that philosophy is useless, they are actually expressing their support for a particular philosophy of science. In principle, there is nothing wrong with this; But the problem is that it is not a good philosophy of science.

On the one hand, Newton, Maxwell, Boltzmann, Darwin and lavoisier, so many great scientists, worked with very different methodological viewpoints and made great scientific work. On the other hand, since Carnap, Popper and Kuhn, the philosophy of science has been developing, and people realize that the ways in which science can develop effectively are far richer and more subtle than those described in the analysis of these thinkers. The mistake of Weinberg and Hawking is that they regard a limited understanding of science limited by historical conditions as the eternal logic of science itself. The weakness of their position is that they don't realize its fragile historical contingency. They regard science as a discipline with a clear and indisputable methodology, as if it has not changed at all since Bacon detected gravitational waves, or as if it is completely obvious what we should do and how to do it in science.

The actual situation is quite different from this. Science is constantly rethinking its own understanding and achievements, methods and tools. This flexibility is very important for its success. Let's consider some examples from physics and astronomy. Inspired by the extremely successful prediction theory of hippies and Ptolemy, the real goal of astronomy is to find a suitable wheel combination to describe the motion of celestial bodies around the earth. But contrary to expectations, the earth itself is one of these celestial bodies. Especially after Copernicus, the real goal became to find a suitable combination of moving spheres to describe the motion of celestial bodies around the sun. But once again, it backfired. It turns out that the abstract ellipsoid orbit is better than the spherical orbit. Later, after Newton, the goal of physics gradually became clear, that is, to find the force acting on objects. Contrary to this plan, facts show that the world is best described by dynamic fields rather than objects. After Faraday and Maxwell, people began to clearly realize that physics is to discover the laws of motion in space with the passage of time. Contrary to the hypothesis, facts show that space-time itself is dynamic. After Einstein, people finally understood that physics must only look for the law of determinism in nature. Contrary to expectations, the facts show that the most we can give is the law of probability. And so on. What is science in the minds of scientists has always had ever-changing definitions, such as finding the ultimate composition of nature from the universal laws of observed phenomena, explaining the laws in empirical observation, and finding a temporary conceptual framework that can make the world meaningful (this last one is my favorite).

Science is not a project completed by carving it in stone. It has a clearly defined object or a fixed conceptual structure. This is our continuous development efforts to better understand the world. In the process of its development, it will repeatedly violate its own standards and methodological assumptions it claims.

The next common description of what scientists are doing-as we learned in school today-is to collect data (observation, experiment, measurement) and explain these data in theoretical form. The relationship between data and theory is complex, and people's understanding of it is still far away, because it is not clear how we get the theory from the data and how the data itself carries the theory. But we ignore this. With the passage of time, we have obtained new data and the theory is constantly developing. In this picture, scientists are described as rational beings who play this game with their wisdom-a special language and a perfect cultural and conceptual structure.

The problem with this picture is that the conceptual structure is also evolving. Science is not only the sum of our ever-increasing empirical information about the world and a series of ever-changing theories, but also the evolution of our conceptual structure. It is our constant pursuit to grasp the best conceptual structure of the world at the present level of knowledge. The revision of conceptual structure needs to be obtained from our own thinking. This is very similar to Quine's wonderful metaphor of otto neurath. A sailor can only repair his ship during the voyage.

The interweaving of "learning" and "concept change", this flexibility and the continuous evolution of this methodology and goal have developed into a lasting dialogue between practical science and philosophical reflection in history. This is the further reason why many sciences are deeply influenced by philosophical reflection. Whether scientists like it or not, this view is permeated with philosophy.

Here we go back to Aristotle: "philosophy provides guidance for studying what must be done."

It is not because philosophy can make the final decision on the correct methodology of science (which is completely contrary to the philosophical positions of Hawking and Weinberg), but because there are many conceptual tools in philosophy that can be used to cope with the constant changes of concepts. Scientists who deny the role of philosophy in scientific progress are those who think they have found the ultimate methodology. Therefore, their ideas are closer to the conceptual flexibility needed in the future. They were captured by the ideology of their time.

spend freely

I think we can give a more powerful example. I believe that one of the reasons for the poor breakthrough in theoretical physics in recent decades is that many physicists today regard the wrong philosophy of science as a treasure. Popper and Kuhn are very popular among theoretical physicists. They have inspired some important aspects of good scientific working methods, but their scientific picture is not complete. I suspect that if their opinions are accepted as routine, it will mislead scientific research. Let's see why this is so.

Kuhn's emphasis on discontinuity and incommensurability misled many theoretical and experimental physicists and made them despise the terrible accumulation of scientific knowledge. Popper's emphasis on falsifiability was originally a demarcation standard, but it was also misunderstood as an evaluation standard. The combination of the two has produced disastrous methodological confusion: when looking for new theories, past knowledge is irrelevant; And all kinds of unproven ideas are equally interesting, and all kinds of unmeasurable effects may occur. The job of a theorist is to let any possibility fall from the sky and then develop them, because everything that has not been falsified may actually be correct.

This is the current "why not do it?" Ideology: any new idea is worth studying just because it has not been falsified; Any idea has the same possibility, because taking a step forward on the road of knowledge will lead to unpredictable Kuhn discontinuity on the basis of past knowledge; Any experiment is equally interesting as long as it detects something that has not been detected.

I think this methodological philosophy has led to a mountain of useless theoretical work and many useless experimental explorations in physics.

It is never an effective way to do science to jump at will in the borderless possibility space. There are two reasons: first, there are too many possibilities, and the probability of accidentally finding a good choice can be ignored; More importantly, nature is always shocking us, and our limited creatures are far from being as creative and imaginative as we think. When we think we have explored far enough, most of the time we are just repeating the same old story in different ways: the innovation that really works can't be found by guessing.

In fact, the most drastic conceptual changes and deviant ideas that really work are always severely stimulated, almost forced by massive new data or a comprehensive analysis of the internal contradictions of existing successful theories. Science operates by continuity, not by discontinuity.

Examples of the former-data-driven innovation-are Kepler's ellipse and quantum theory. Kepler didn't just "suddenly" think of using an ellipse: before he saw the ellipse, nature had "sprinkled" the ellipse on his face. He used an ellipse to approximate the current circular-even wheel motion of Mars, and was shocked that this approximation was better than his original model. Similarly, at the beginning of the 20th century, parents of atomic physics struggled with the concept of discontinuity contained in the basic laws and tried their best to reject the clear information given by spectroscopy. In other words, the core part of mechanics actually appears discontinuity. In both cases, important new ideas are forced to appear in front of data.

Examples of the second case-the radical innovation of the old theory-are Heliocentrism and the general theory of relativity. Neither Copernicus nor Einstein relied much on new data. They all started with a profound analysis of successful and recognized theories: Ptolemy's astronomy, Newton's gravity and special relativity. The contradictions and unexplained coincidences they found opened the way for new conceptual ideas.

In either case, it is more than just fishing out some theories that have not been falsified and then testing the results they bring. On the contrary, it is based on extensive accumulated experience and theoretical knowledge, and the clever use of induction provides us with clues for progress. Only by carefully examining the successful insights in experience can we move forward. Einstein's "theory of relativity" is not a "new idea": it is Einstein's understanding of why Galileo's theory of relativity can be established on a large scale. There is no discontinuity here: in fact, it is the best continuity. This is Einstein's insightful "conservatism" when those people are eager to abandon the relativity of speed just because of Maxwell's equation.

I think this lesson has been ignored by too much contemporary theoretical physics work, and a lot of research directions are too eager to abandon what we have discovered about nature.

Ironically, in fact, the recent great progress in experimental physics is a refutation of the random guessing style in theoretical physics today. Recently, there are three experimental results in basic physics: gravitational waves, Higgs particles and LHC lack supersymmetry. All three have verified the old physics and denied the widespread speculation. In these three examples, nature tells us not to guess so casually. Let's take a closer look at these examples.

The detection of gravitational waves awarded the Nobel Prize in Physics is a complete confirmation of the general theory of relativity that has existed for a century. But it's more than that. Recently, the gravitational and electromagnetic signals generated by the merger of two neutron stars detected almost simultaneously (this event is called GW 1708 17) have improved our understanding of the ratio of gravitational and electromagnetic field propagation speed by 14 orders of magnitude. The consequence of this huge accumulation of our empirical knowledge is that we have to rule out a large number of alternatives to general relativity, and a large number of theorists have been studying these alternatives in recent decades-at the same time, it has been confirmed that general relativity with a history of one hundred years is the best theory about gravity at present.

The fact that Higgs particles were detected in CERN was widely publicized, which confirmed that the standard model of particle physics (founded by Weinberg et al.) was the best existing theory of high energy physics, and refuted the alternatives that attracted much attention later.

When the Large Hadron Collider was put into operation in Geneva, CERN's emphasis on the discovery of Higgs particles also concealed the real accident exposed in this special exploration of high-energy physics: supersymmetric particles did not exist, although a generation of theoretical physicists expected to find them. Although pen and ink converge into a river and imagination keeps flying, the minimum supersymmetric standard model suddenly finds itself in deep trouble. Therefore, Nature once again seriously rejects these arbitrary speculations that many theoretical physicists believe.

In my opinion, nature's repeated delay in the methodology of current theoretical physics should make us remain modest in our philosophical attitude, not furious.

I suspect that part of the reason for this problem is that the dominant ideas of Popper and Kuhn misled the current theoretical inquiry. Physicists attach too much importance to the established theory of success. Because Kuhn's emphasis on the incommensurability across the scientific revolution misled them, they could not build from what people knew, which is exactly the way science has been advancing. A good example is that many attempts to integrate gravity into other parts of basic physics give up the background independence in general relativity.

In addition, the emphasis on falsifiability makes many physicists fall into ignorance of a fundamental aspect of scientific knowledge: that is, there is a degree of reliability, and the degree of credibility can reach a high level, even if it is not completely certain. This ignorance leads to double negative effects: in the progress of science, the insights in the theory of success are considered irrelevant (because they may be falsified tomorrow), and ignorance of an exploration may have only a small credibility even if it is not falsified.

Scientific undertakings are based on reliability. Based on new data or new theoretical development, this reliability will be constantly updated. Bayesian interpretation of evidence, which has recently attracted the attention of the scientific community, is very common in philosophy of science, but it is mostly ignored in theoretical physics. In my opinion, this has a negative effect.

What I want to do here is not to criticize Popper and Kuhn. Their works are clear and insightful. What I want to point out is that some simple versions of their views are too casually taken as the final conclusion of scientific methodology by many physicists.

Far from being immune to philosophy, contemporary physics is deeply influenced by philosophy. However, the source of weakness in physics is the lack of philosophical awareness needed to realize this influence and the refusal to listen to the opinions of philosophers trying to make up for this influence.

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The following is the last argument of the "encouragement article":

The more science is in serious confusion and confusion, the more it needs philosophy.

Today's basic physics is undergoing a profound conceptual change, which is due to the success of general relativity and quantum mechanics, and there is still a quantum theory of gravity that can be recognized by people (in Kuhn's sense; I prefer to call it "opportunity". This is why some scientists who do quantum gravity, including myself, are more keenly aware of the importance of philosophy to physics.

The following are some topics discussed by the most theoretical physics circles at present: What is space? What is the time? What is it now? Is the world deterministic? Do we need to introduce observers to describe nature? Is physics better structured according to "reality" or "what we observed", or is there a third choice? What is quantum wave function? What does "emerging" mean? Is it meaningful to describe the universe The Theory of Everything? Is it meaningful to think that the laws of physics are also evolving? For me, discussing these topics, the nourishment of philosophical thinking from ancient times to the present is obviously not to be ignored.

In the technical field of loop quantum gravity, Newton's space-time is reinterpreted as something granular, probabilistic and fluctuating in the quantum sense. Space, time, particles and fields merge into a single entity: a quantum field that does not exist in time or space. Variables in this field only require the clarity of the interaction between subsystems. The basic equation of this theory has no definite time or space variables. Geometry only appears in approximations. This object exists in the approximate value. Realism is reconciled by powerful relational theory. I think we physicists need to discuss with philosophers, because I think we need their help to understand these things.

Land (dry)

Finally, I want to talk briefly about the opposite problem: the correlation between science and philosophy.

The reason why I want to talk about this is only because some remarks made by the scientific community about philosophy are just a response to the anti-scientific attitude of some fields of literature such as philosophy.

Now there is a post-Heidegger atmosphere in some philosophy departments in mainland China, and ignorance of science has become something to be proud of. Science is not "real" knowledge; It misses the real knowledge. "... botanists' plants are not flowers beside the fields; The' source' of rivers demarcated by geographers is not the' source of valleys'. This context implies that only Flowers by the Field and The Source of the Valley are important.

Sociology, another branch of today's intellectual circles, also has an example: "No one has the obligation to adopt a world view to describe the scientific development of the 20th century". This statement is either boring ("no one forces you to be intelligent") or misleading. The so-called "misleading" means "leading in the wrong direction" in the etymological sense.

I understand now: just as the best science is closely related to philosophy, so is the best philosophy. Obviously, this has always been the case: from Aristotle and Plato, to Descartes and Hume, to Kant and Hegel, to Husserl and Louis, the best philosophy is always closely coordinated with science. In the past, no great philosopher took seriously the knowledge provided by the science of their time.

The history of science is an indispensable part of our culture. It is far from answering all the questions we want to ask, but it is still an extremely powerful tool. It can deal with countless problems, including those that concern ourselves and those that discuss the whole universe. All our knowledge is the result of many contributions from very different fields, from science to philosophy, of course, literature and art, and our ability to integrate them. In my opinion, philosophers who belittle science-many of them-are seriously hurting reason and civilization. When they say that all fields of knowledge can't penetrate into science and that they are the ones who know more, they remind me of two little old men sitting on a park bench: "Ah", one of them said with a trembling voice, "Look at these scientists who claim to be able to study consciousness and the origin of the universe." "Oh," said another, "that's ridiculous! Of course they don't understand. We can! "