Physics needs philosophy, and philosophy needs physics

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"Science and Culture Review" Issue 2, 2019, pp. 107-119 .

The "opposition philosophy" is a great contemporary physicist - Steven Weinberg, winner of the Nobel Prize in Physics and founder of the "Standard Model" of elementary particle physics - —The title of a chapter in the book I wrote. Weinberg eloquently argued that philosophy hurts physics more than it helps—while it may sometimes provide good insights, it is often a straitjacket that physicists themselves have to shed. Even more radically, Stephen Hawking famously wrote that “philosophy is dead.” His reasoning is that big questions that used to be left to philosophers are now being taken over by physicists. Similar sentiments are widespread among scientists, and they make no secret of it. Neil de Grasse Tyson, a well-known figure in the American science popularization circle, publicly declared in the same style: "...we understand the expanding universe,...we understand quantum physics,...this Each of these is far beyond what the entire community of philosophers could deduce from their seats... (They are) essentially out of date."

I disagree with these opinions. In this article I give some counter-arguments by arguing that philosophy has always played an essential role in the development of science, especially physics, and, presumably, will continue to do so.

This is a long-standing debate. Regarding this, there was an interesting scene in Athens during the classical period. At that time, the young people in the city who were in their golden years were educated in famous schools. Two schools stand out: the school of Isocrates and the Academy founded by Plato. The competition between the two is fierce, like that between Cambridge and Oxford, but it's not just about quality: the educational approaches between the two schools are very different. Isocrates provided a high level of practical education, teaching young people in Athens the skills and knowledge they needed to become politicians, lawyers, judges, architects, etc. The academy, on the other hand, focuses on 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 a good name: philosophy.

The differences between the two academic schools are deep-rooted. Isocrates criticized Plato's method of acquiring education and knowledge very directly:

Those who do philosophy, those who judge proofs and arguments... are accustomed to questioning, but they are practice duty but never contribute... Even if they happen to have the ability to control something, they automatically break it, and those who have no knowledge of (philosophical) argumentation, if they are trained in (concrete scientific) And have the right perspective and actually all do better. So for science, philosophy is useless.

This is clearly similar to the view of contemporary scientists who believe that philosophy has no role in science.

It happened that an outstanding young student in Plato’s Academy wrote a short essay in response to Isocrates’ criticism. This is the famous ancient article - "Protrepticus". Only part of it survives, and we know about it only through reconstructions from numerous citations by later generations. A group of classical scholars led by Doug Hutchinson and Monte Ransome Jonson recently completed a new reconstruction of it, now available online. The Exhortation is probably written in the form of a dialogue between two people defending two opposing positions. The surviving portions of the text are sufficient to allow one to understand the main arguments advanced by the young student in defense of philosophy in response to Isocrates.

The clever young man left Athens after writing this pamphlet, but eventually returned to open his own academy and a successful career. His name was Aristotle.

The developments in science and philosophy over the past 2000 years not only confirmed - and more likely - strengthened Aristotle's defense of philosophy against Isocrates' charge of its futility.

His argument still seems pertinent, and I was inspired to respond here to current assertions that philosophy is useless for physics.

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Aristotle’s first argument comes from the fact that:

General theories can support and often help practice progress.

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

Today, 2000 years have passed. During this period, both philosophy and science have developed significantly, and there are countless historical evidences of the influence of philosophy on science.

Here are some examples from astronomy and physics that illustrate this effect. I will mention just a few examples. In ancient astronomy, all we know is that the earth is round and its size, the size of the sun and the moon, the distance from the earth to the sun and the moon, the movement of the planets in the sky, and modern astronomy and modern physics Some of the foundations upon which science arose; and this ancient astronomy was a direct product of philosophy. The core questions that led to these developments were raised in the Academy and Lyceum, and they emerged from theoretical rather than practical concerns. Even though many centuries later Galileo and Newton made huge strides forward from their previous knowledge of physics and astronomy—particularly the Aristotelian worldview—they still relied heavily on what they had learned before Results. Galileo and Newton expanded upon previous knowledge, reinterpreted it, reframed it, and built upon it something new. In particular, Galileo's thinking would appear unreasonable without Aristotle's physics.

More importantly, without Galileo's tracing of Plato's thought, that is, his pursuit of the ideal mathematical order hidden behind the appearances, his work would be unreasonable. Galileo was guided by a fervent Platonism. In his works, Newton also clearly showed that many of his ideas borrowed from ancient philosophy, especially Democritus, such as concepts such as empty space, atomism, and natural linear motion, which originally originated from Philosophically motivated. In addition, his important discussions on the nature of time and space were based on the discussions and arguments between him and Descartes.

However, the direct influence of philosophy on physics is by no means limited to the period when modern physics was just born. This influence can be seen in every important step of progress. For example, in the 20th century: Two major developments in physics in the 20th century were strongly influenced by philosophy. Without a philosophy of time, they would be incomprehensible. Quantum mechanics originated from Heisenberg's intuition, which was rooted in his perception of the strong positivist philosophical atmosphere in which he was living at the time: knowledge can only be gained from observable things. Heisenberg's foundational paper of 1925 made this point explicit:

The goal of this work is to lay the foundations for a theory of quantum mechanics based solely on relationships between observable quantities in principle.

Similarly, it was an apparently philosophical attitude that led Einstein to discover special relativity: by limiting the scope to observables, we realize that the concept of simultaneity is misleading. Einstein explicitly acknowledged his debt 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 was influenced even more strongly by philosophy. Once again he explicitly acknowledges his debt to philosophy, this time from the critical thinking of Leibniz, Berkeley and Mach. Einstein's relationship to philosophy was indeed complex: for example, he admitted that Schopenhauer had been a convincing influence on him. This is less obvious in his physics, but Schopenhauer's ideas about time and appearance may not be difficult to discern in Einstein's ideas that led to general relativity; this influence has also been studied Pass. Is it really a coincidence that the greatest physicist of the 20th century had such an obvious focus on philosophy when he was young - he read Kant's three Critiques at the age of 15?

Why are there these effects? Because philosophy can provide methods for generating new ideas, novel perspectives, and critical thinking.

Philosophers have the tools and skills required in physics, but these are missing in the training and development of physicists: conceptual analysis, attention to ambiguity, precision in expression, finding in standard arguments The ability to identify gaps, create new perspectives, discover conceptual weaknesses, and identify alternative conceptual explanations. No one put it better than Einstein himself:

Knowledge of the historical and philosophical background gives us the kind of independence from the prejudices into which most scientists of our generation fall. This independence brought about by philosophical insight is—in my opinion—what distinguishes the mere craftsman or expert from the true seeker of truth.

Sometimes, a stronger statement is made: "Scientists can do nothing without first getting permission from philosophy."

Thus, if you read the greatest What scientists have said about the usefulness of philosophy, such as Heisenberg, Schr?dinger, Bohr, and Einstein, we will find that the opinions they expressed are completely opposite to those of Hawking and Weinberg.

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The following is Aristotle's second argument:

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

This is by no means as boring as it first seems. Let's examine what Weinberg and Hawking wrote. Both of them achieved significant scientific results. Weinberg, for example, found the correct symmetry group that describes the interactions between elementary particles, while Hawking discovered that black holes are hot and calculated their temperatures. In doing things like this, they're doing science. When they write things like "Philosophy has no use for physics" or "Philosophy is dead", they are not doing physics. So what are they doing? They are reflecting on what is the best way to develop science.

The problem here is the methodology of science. A central concern in the philosophy of science is, of course, to ask carefully how science is done, and how it might be done more effectively. It’s good that good scientists reflect on their own methodologies, and Weinberg and Hawking did. But so what?

They express a certain idea about scientific methodology. Is this the eternal truth about how science has always worked and should work? Is this the best understanding of science we have?

Neither. It is not difficult to trace the origin of this concept. It originated from the background of logical positivism, which was later modified by Popper and Kuhn. The current mainstream methodological ideology in theoretical physics comes from their two concepts of falsifiability and scientific revolution, both of which are very popular among theoretical physicists; they are often mentioned and Commonly used to guide research directions and evaluate research efforts.

So in asserting the futility of philosophy, Weinberg, Hawking and other "anti-philosophical" scientists are actually paying homage to certain philosophers of science, who may Have read their works or absorbed their concepts in their environment. It is impossible to go wrong with this imprint. When they view philosophy as a bunch of false propositions - propositions made up of words that have no proper meaning - a bunch of them are repeatedly mocked like Neil de Grasse Tyson. It is not difficult to trace these criticisms back to the anti-metaphysical stance of the Vienna Circle. Behind these curses against philosophy, one can almost hear the slogan of the Vienna Circle: "No metaphysics!"

So when Weinberg and Hawking claimed that philosophy was useless, they were actually expressing their disapproval of it. Supported by a specific philosophy of science. In principle, there's nothing wrong with this; the problem is, it's not a good philosophy of science.

On one side are Newton, Maxwell, Boltzmann, Darwin, Lavoisier and so many great scientists. They work with very different methodological perspectives (from the above-mentioned stance) and have made extraordinary achievements. Great scientific work. On the other hand, the philosophy of science since Carnap, Popper, and Kuhn has been evolving with the recognition that the ways in which science can be effectively conducted are far richer and more nuanced than depicted in the analyzes of these thinkers.

The mistake of Weinberg and Hawking was to regard a specific, limited understanding of science, limited by historical conditions, as if it were the eternal logic of science itself. The weakness of their position lies in the failure to recognize its fragile historical contingency. They treat science as a discipline with a clear and uncontroversial methodology, as if nothing has changed from Bacon to the detection of gravitational waves, or as if it is completely obvious what we should do and how to do it when doing science. of.

The actual situation is quite different. Science is constantly rethinking its understanding of itself and its achievements, methods, and tools. This flexibility is important to its success. Let's consider some examples from physics and astronomy. Inspired by the extraordinarily successful predictive theories of Hipparchus and Ptolemy, the real goal of astronomy was to find the right combination of wheels to describe the motion of celestial bodies revolving around the Earth. But contrary to expectations, it turns out that Earth itself is one of these celestial bodies. And especially after Copernicus, the real goal became to find the right combination of moving spheres to describe the motion of celestial bodies revolving around the sun. But again contrary to expectations, it turns out that abstract ellipsoidal orbits are better than spherical ones. Later, after Newton arrived, the goal of physics gradually became clear, which is to find the force acting on an object. Contrary to this scheme, it turns out that the world is best described in terms of dynamical fields rather than objects. After Faraday and Maxwell, it became clear that physics is about finding the laws of motion in space over time. Contrary to assumptions, it turns out that spacetime itself is also dynamic. After Einstein, it finally became clear that physics had to look only for deterministic laws in nature. Contrary to expectations, it turns out that we can at best give probabilistic laws. And so on. There have been ever-changing definitions of what scientists think science is, such as: general laws derived from observed phenomena, finding the ultimate composition of nature, explaining rules in empirical observations, and finding ways to make sense of the world. of tentative conceptual frameworks (this last one is my favorite).

Science is not a project written in stone, with defined objects, or with a fixed conceptual structure. It is our ever-evolving effort to better understand the world. In the course of its development it will repeatedly violate its own norms and its own stated methodological assumptions.

A common current description of what exactly scientists do - as we learn in school today - is to collect data (observations, experiments, measurements) and present them in the form of theories Talk through the data. The relationship between data and theory is complex, and people are far from reaching a complete understanding of it, because it is not clear how we obtain theory from data, and it is also unclear how the data itself carries theory. -laden). But let's ignore that. Over time, we acquire new data and the theory evolves. In this picture, scientists are described as rational beings who play the game with their intellect - a special language and a well-established cultural and conceptual structure.

The problem with this picture is that this conceptual structure also evolves. Science is not just the sum of our ever-increasing empirical information about the world and a string of changing theories; it is also the evolution of our conceptual structures. It is our constant pursuit of the best conceptual structure to grasp the world based on our existing knowledge level. Revisions to conceptual structures need to be derived from our own thinking. It's very much like that wonderful metaphor written by Otto Neurath that Quine often cites - that a sailor can only mend his ship as he sails.

The intertwining of "learning" and "conceptual change", this flexibility, and this continuous evolution of methodologies and goals have historically developed into a relationship between practical science and philosophical reflection. lasting dialogue. This is a further reason why much science has been profoundly influenced by philosophical reflection. This view of scientists, whether they like it or not, is steeped in philosophy.

Here we return to Aristotle: “Philosophy provides guidance for the study of what must be done.

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It is not because philosophy can give a final word on the correct methodology of science (this is exactly the opposite of the philosophical stance of Hawking and Weinberg), but because there are many conceptual tools in philosophy that can be used to deal with concepts. Continuous change. Scientists who deny the role of philosophy in scientific progress are the ones who think they have found the ultimate methodology. As a result, their minds are more closed to the conceptual flexibility they need. I think a stronger example can be given of the reason why the breakthroughs in theoretical physics in recent decades are relative. Poor, one reason is that many physicists today treasure the wrong philosophy of science. Popper and Kuhn - so popular among theoretical physicists - shed light on some important aspects of how good science works. , but their scientific picture is incomplete. I suspect that if they are accepted as conventions, it will mislead scientific research.

Kuhn. The emphasis on discontinuity and incommensurability has misled many theoretical and experimental physicists into underestimating the terrible cumulative aspect of scientific knowledge. Popper's emphasis on falsifiability was originally a problem. This demarcation criterion has also been misunderstood as a criterion for evaluation. The combination of the two produces a disastrous methodological confusion: in the search for new theories, past knowledge is irrelevant; Proven ideas are all equally interesting, all kinds of unmeasured effects are equally likely to occur, and the theorist's job is to let random possibilities fall from the sky and then develop them, because everything that is not falsified is actually It may be true.

This is the current "why not do it?" "Ideology: Any new idea is worthy of study simply 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 unforeseen consequences based on past knowledge. Kuhnian discontinuity; any experiment is equally interesting as long as it detects something that has not been measured.

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

Jumping arbitrarily in an unbounded possibility space is never an effective way to do science. The reasons are twofold: first, there are too many possibilities. The probability of finding a good choice purely by chance is negligible; more importantly, nature always shocks us that we, finite creatures, are far less creative and imaginative than we think we are. When we test far enough, most of the time we are just repeating the same old story in a different way: the innovations that really work cannot be found by just guessing.

The ones that really work. The most radical conceptual shifts and the most outrageous ideas are in fact always rigorously provoked and almost forced out by a flood of new data or a thorough analysis of the inherent contradictions of an existing successful theory. Science is. Operating on continuity, not discontinuity

Examples of the former—innovations forced by data—are Kepler’s ellipses and quantum theory Kepler didn’t just “take risks.” The "idea" of using ellipses came out: before he saw an ellipse, nature had to "splash" it in his face. He used ellipses to approximate the epicycle-deferent motion of Mars, and was shocked by This approximation worked better than his original model. Similarly, atomic physicists in the early 20th century struggled with the notion of discontinuity in their fundamental laws, doing their best to reject the clear message that spectroscopy had given them. In other words, discontinuities have emerged at the very core of mechanics. In both cases, important new ideas are forced to emerge in the face of data.

The second case. - Radical innovations derived from older theories - neither Copernicus nor Einstein relied significantly on new, accepted theories. Begin with a profound analysis: Ptolemaic astronomy, Newtonian gravity, and special relativity. The contradictions and unexplained coincidences they uncover open the way to new conceptual ideas.

No matter what. In this case, it is not just about fishing out some theories that have not been falsified and then testing the results they bring.

Rather, it is the clever use of induction, based on extensive and accumulating empirical and theoretical knowledge, that provides us with clues to move forward. We can move forward by carefully examining insights that have been empirically successful. Einstein's "theory of relativity" is not a "new idea": it is Einstein's understanding of why Galileo's theory of relativity holds true in a wide range of situations. There is no discontinuity here: in fact, it is an optimal continuity. This was Einstein's insightful "conservatism" in the face of those who were eager to abandon velocity relativity simply because of Maxwell's equations.

I think this lesson is ignored by too much contemporary work in theoretical physics, and a large number of research directions are too eager to throw away what we have found about nature.

Ironically, recent major advances in experimental physics are actually a refutation of today's random guessing style in theoretical physics. Recently, three major experimental results have appeared in basic physics: gravitational waves, the Higgs particle, and the lack of supersymmetry in the LHC. All three verified old physics and disproved widely circulated speculation. In these three examples, nature tells us: Don’t guess so haphazardly. Let's take a closer look at these examples.

The detection of gravitational waves - which has been awarded the Nobel Prize in Physics - is complete confirmation of the century-old general theory of relativity. But it's more than that. The recent almost simultaneous detection of the gravitational and electromagnetic signals caused by the merger of binary neutron stars (this event is called GW170817) has once again improved our understanding of the ratio of the propagation speeds of gravity and electromagnetic fields by 14 orders of magnitude. The consequence of this significant accumulation of our empirical knowledge is that we have had to rule out a host of alternatives to general relativity, which a large group of theorists have been working on in recent decades—while simultaneously confirming the century-old general theory of relativity. This is currently the best theory about gravity.

The detection of the Higgs particle at CERN has been widely publicized, confirming that the Standard Model of particle physics (created by Weinberg and others) is the best available version of high-energy physics theory, countering subsequent alternatives that received much attention.

While the Large Hadron Collider was already operational in Geneva, CERN's emphasis on the discovery of the Higgs particle also concealed the real surprise revealed in this particular exploration of high-energy physics: supersymmetry. Particles don't exist, despite a generation of theoretical physicists hoping to find them. Despite the river of pen and ink and the rapid flight of imagination, the minimal supersymmetric standard model suddenly found itself in deep trouble. So once again, nature seriously rejects these arbitrary guesses that legions of theoretical physicists believe.

I think that nature’s repeated slowdown on the current methodology of theoretical physics should inspire us to maintain a certain degree of humility in our philosophical attitude, rather than being furious.

I suspect that part of this problem lies in the fact that the dominant ideas of Popper and Kuhn have misled current theoretical inquiry. Physicists take established and successful theories too seriously. Misled by Kuhn's emphasis on incommensurability across scientific revolutions, they were unable to build from what was known, which is how science has always progressed. A good example is that many attempts to integrate gravity into other parts of fundamental physics abandon the background independence of general relativity.

Furthermore, the emphasis on falsifiability has led many physicists into ignorance of a fundamental aspect of scientific knowledge: namely, that there are degrees of reliability, and that the degree of trustworthiness can reach very high levels. high, even if not completely certain. This ignorance leads to a double negative effect: to dismiss insights from successful theories as irrelevant in the progress of science (because they might be disproven tomorrow), and to fail to understand that an exploration can be carried out even if it has not yet been disproven. Falsification may also have little credibility.

The scientific enterprise is built on a degree of reliability, and this reliability will be continuously updated based on new data or new theoretical developments. The Bayesian interpretation of confirmation, which has attracted recent attention in the scientific community, is common in the philosophy of science, but has been largely ignored in the theoretical physics community. In my opinion, this has a negative effect.

What I want to do here is not a criticism of Popper and Kuhn. Their writing is clear and insightful.

What I would like to point out is that some simple-minded versions of their views are too casually accepted by many physicists as the last word on scientific methodology.

Contemporary physics is far from being "immune" to philosophy, but is deeply influenced by philosophy. But the lack of philosophical awareness required to recognize this influence, and the refusal to listen to philosophers who try to remedy it, is the source of physics' weaknesses.

Wu

The following is the last argument in "Exhortation":

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

Today's basic physics is undergoing a profound conceptual change. This is due to the success of general relativity and quantum mechanics, and the current lack of a recognized quantum theory of gravity. resulting in an open "crisis" (in Kuhn's sense; I would rather call it an "opportunity"). This is why some scientists, including myself who work on quantum gravity, are more keenly aware of the importance of philosophy to physics.

Here are some of the topics currently discussed in theoretical physics: What is space? What is time? What is now? Is the world deterministic? Do we need to introduce observers to describe nature? Is physics better framed in terms of "reality" or in terms of "what we observe", or is there a third option? What is a quantum wave function? What exactly does "emergence" mean? Do theories that purport to describe the universe as a whole make sense? Does it make sense to think that the laws of physics are also evolving? It is clear to me that in approaching these topics, the nourishment of philosophical thinking from the past and the present cannot be ignored.

In loop quantum gravity, my own technical field, Newtonian space-time is reinterpreted as being represented by something that is granular, probabilistic, and fluctuating in the quantum sense. Something that comes out. Space, time, particles and fields merge into a single entity: a quantum field that does not exist in time or space. Variability of such fields requires only explicitness of the interactions between subsystems. The theory's basic equations have no explicit time or space variables. Geometry appears only in approximations. Objects exist in approximations. Realism is tempered by a strong relationalism. I think we physicists need to talk to philosophers because I think we need their help figuring this stuff out.

Lu

Finally, I would like to briefly talk about the opposite aspect: the relevance of science to philosophy.

The reason why I want to talk about this is just because some of the opposition to philosophy in the scientific community is just a response to the anti-scientific attitude in some areas of philosophy and other humanities disciplines.

A post-Heideggerian atmosphere now dominates some philosophy departments on the "continent", in which ignorance of science is something to be proud of. Science is not "real" knowledge; it misses real knowledge. "...the botanist's plants are not the field-side flowers; the geographer's 'origin' of the river is not the 'god of the glen'." This context implies that only the "field-side flowers" and "the head of the glen" are important. of.

There is also an example in sociology, another branch of today's intellectual circles: "No one is obliged to adopt a specific worldview to describe the scientific development of the 20th century." This argument is either boring ("no one forces you to be intelligent") or misleading, in the etymological sense of "leading in the wrong direction."

I understand this now: just as the best science is closely tied to philosophy, the best philosophy will be closely tied to science. This has obviously always been the case in the past: from Aristotle and Plato, to Descartes and Hume, to Kant and Hegel, to Husserl and Lewis, the best philosophy has always been closely coordinated with science. There have never been any great philosophers in the past who did not take seriously at all times the knowledge provided by the science of their time.

The history of science, an integral and essential part of our culture. It's still far from answering all the questions we want to ask, but it's still an extremely powerful tool. It can deal with countless problems, including those that concern ourselves and the universe as a whole. All of our knowledge is the result of many contributions from very different fields, from science to philosophy and of course literature and art, and our ability to integrate them.

It seems to me that those philosophers who disparage science—and there are many of them—are doing a serious disservice to sanity and civilization. When they say that all fields of knowledge do not penetrate into science, and that they are the ones who know better, they remind me of those two little old men sitting on the park bench: "Ah," one of them trembles "Look at these scientists who claim to be able to study consciousness and the origin of the universe." "Oh," said another, "How ridiculous! Of course they don't understand. We are the ones who can!"