I'll probably be making a lot of posts on this topic, but to inaugurate this blog, I'll share my thoughts on one of the main articles in the 2011-2012 "kerfuffle" between (some) physicists and (some) philosophers, a New York Times opinion piece by Jim Holt, author of Why Does the World Exist?: An Existential Detective Story (which is not bad by the way, it's worth reading).
The original story was posted here.
Holt begins:
A KERFUFFLE has broken out between philosophy and physics. It began earlier this spring when a philosopher (David Albert) gave a sharply negative review in this paper to a book by a physicist (Lawrence Krauss) that purported to solve, by purely scientific means, the mystery of the universe’s existence. The physicist responded to the review by calling the philosopher who wrote it “moronic” and arguing that philosophy, unlike physics, makes no progress and is rather boring, if not totally useless. And then the kerfuffle was joined on both sides.
This is hardly the first occasion on which physicists have made disobliging comments about philosophy. Last year at a Google “Zeitgeist conference” in England, Stephen Hawking declared that philosophy was “dead.” Another great physicist, the Nobel laureate Steven Weinberg, has written that he finds philosophy “murky and inconsequential” and of no value to him as a working scientist. And Richard Feynman, in his famous lectures on physics, complained that “philosophers are always with us, struggling in the periphery to try to tell us something, but they never really understand the subtleties and depths of the problem.”
Why do physicists have to be so churlish toward philosophy? Philosophers, on the whole, have been much nicer about science. “Philosophy consists in stopping when the torch of science fails us,” Voltaire wrote back in the 18th century. And in the last few decades, philosophers have come to see their enterprise as continuous with that of science. It is noteworthy that the “moronic” philosopher who kicked up the recent shindy by dismissing the physicist’s book himself holds a Ph.D. in theoretical physics.I'm going pass quickly over the question of how accurate these quotes are as a portrayal of those physicists' attitudes towards philosophy. Suffice to say, as an avid reader of all three physicists in the second paragraph, I'd agree that Hawking's attitude towards philosophy is bizarre, but I don't think these simple quotes do justice to the nuance of the others' views on philosophy, which I would characterize as more a wry ambivalence[1] -one that many naturalist philosophers, if less blunt language was used, would find agreeable- than simple dismissal. And on the matter of "niceness," I cannot help but see this as more a matter of academic politics than intellectual substance. After all, many philosophers have been rather acerbic about the "philosophical tradition."[2] I think we should just set the issue of "niceness" to the side, as I think most parties involved would agree that what they're interested in is truth.
Holt continues:
Physicists say they do not need any help from philosophers. But sometimes physicists are, whether they realize it or not, actually engaging in philosophy themselves. And some of them do it quite well. Mr. Weinberg, for instance, has written brilliantly on the limits of scientific explanation — which is, after all, a philosophical issue. It is also an issue about which contemporary philosophers have interesting things to say.
Mr. Weinberg has attacked philosophical doctrines like “positivism” (which says that science should concern itself only with things that can actually be observed). But positivism happens to be a mantle in which Mr. Hawking proudly wraps himself; he has declared that he is “a positivist who believes that physical theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality.” Is Mr. Hawking’s positivism the same positivism that Mr. Weinberg decries? That, one supposes, would be an issue for philosophical discussion.I'm going to be a stereotypical "analytic" philosopher and engage in a bit of logic-chopping here. Holt makes the jump from "Physicists say they do not need any help from philosophers" to "But sometimes physicists are...actually engaging in philosophy themselves." One can coherently, however, suppose that physicists are "doing philosophy" but don't need help from those officially designated by the divisions of today's academy as "philosophers." I would say that oftentimes scientists do "philosophy" (in the sense employed by Holt) better than official philosophers themselves.[3]
What Holt -and many other partisans of philosophy- is decrying here is a sort of "scientific imperialism" or "scientism" on the part of scientists. The problem is that I can just flip this accusation around. Indeed, it often seems to me that philosophers are to some extent projecting with their accusations of scientism, as they are engaging in a sort of philosophical imperialism. As James Ladyman and Don Ross say in their book Every Thing Must Go, such philosophers deplore the supposed philosophical "naivety" of scientists in what is really just an attempt to "domesticate" the findings of science[4], to cram the counter-intuitive and difficult ideas of modern science into (relatively) comfortable intuitive philosophical frameworks. They argue that scientists "don't understand" the implications of their own discoveries, when to me it often seems that what is actually going on is that the philosophers are unwilling (or unable) to really accept the science at face value.
Furthermore, if the "philosophical" contention that philosophy is just very general and very abstract science -a common one among naturalists- is correct, then the above is rendered more plausible. Sure, one could on this basis contend that all scientists are to some extent doing philosophy in a tacit fashion, and thus need help from the self-conscious philosophers. But I can just turn this around and say that what philosophers are doing is for the most part just bad science, so that philosophy's domain being made ever smaller by the "official" sciences, and what's left being as informed as much as possible by science, is a good thing. Just because philosophy as a field was chronologically antecedent to science doesn't necessarily imply any particular conceptual relationship between the two fields. It could just be historical accident. Of course, none of these assertions are self-evidently true and I don't wish to shut down discussion of the issue; quite the opposite. But these sorts of "anti-philosophical" worries seem like ones that should be taken extremely seriously, and the partisans of philosophy qua academic discipline seem to be glossing over them in a manner similar to what they accuse their opponents of.
The physicist Sir Roger Penrose is certainly not a positivist. He is a self-avowed “Platonist,” since he believes (like Plato) that mathematical ideas have an objective existence. The disagreement between Mr. Hawking the positivist and Mr. Penrose the Platonist — a philosophical one! — has hard scientific consequences: because of it, they take radically opposed views of what is going on when a quantum measurement is made. Is one of them guilty of philosophical naïveté? Are they both?
Finally, consider the anti-philosophical strictures of Richard Feynman. “Cocktail party philosophers,” he said in a lecture, think they can discover things about the world “by brainwork” rather than by experiment (“the test of all knowledge”). But in another lecture, he announced that the most pregnant hypothesis in all of science is that “all things are made of atoms.” Who first came up with this hypothesis? The ancient philosophers Leucippus and Democritus. And they didn’t come up with it by doing experiments.I don't disagree that the realism/anti-realism (or as it has been more recently called, the realism/empiricism debate) has scientific implications, but this seems to me trivial. It's not so much an issue of the foundations of quantum mechanics qua quantum mechanics as it is the ontological status of anything described by scientific theories. Furthermore, Penrose's small-P platonism is not just about scientific realism generally (though I have no doubt from his writings that he is a realist), but the existence of mathematical objects in particular.[5]
Feynman's point I think is more significant, and I think Holt misses it. First, it's worth noting that Feynman is opposed to "Cocktail party philosophers" in particular, not anything that might conceivably be done under the banner "philosophy." With his emphasis on experiment, I would interpret this remark as an opposition to armchair metaphysics and certain versions of conceptual analysis in particular, which again many naturalists (including myself) would find perfectly agreeable. And Feynman certainly doesn't deny that the Greek atomists came up with the atomic hypothesis in its basic form. What's important about modern science is that it has vindicated that hypothesis experimentally. To point out that a past philosopher has hypothesized an idea that would later be confirmed by science is certainly interesting, but doesn't really have much to do with Feynman's point.
Today the world of physics is in many ways conceptually unsettled. Will physicists ever find an interpretation of quantum mechanics that makes sense? Is “quantum entanglement” logically consistent with special relativity? Is string theory empirically meaningful? How are time and entropy related? Can the constants of physics be explained by appeal to an unobservable “multiverse”? Philosophers have in recent decades produced sophisticated and illuminating work on all these questions. It would be a pity if physicists were to ignore it.For the most part, where the philosophers in question are scientifically competent, the physicists haven't ignored the work. Instead, the've taken from it what is useful rather than swallowing the philosophers' entire self-image of the relationship between the disciplines. Just grabbing the nearest physics book on my shelf (Sean Carroll's From Eternity to Here, a book about time), the cited authors include the very David Z. Albert of Holt's article, as well as Huw Price and Craig Callender. And even when scientists like Krauss are a little too hasty in their rejection of philosophy, it's not like philosophy isn't guilty of wronging science. Just off the top of my head, I am reminded of Ludwig Boltzmann's suicide. Boltzmann's kinetic theory of gases presupposed the existence of atoms, but the acceptance of this (correct) theory was delayed past Boltzmann's lifetime because of distinctly philosophical arguments against the possibility of atoms.
Finally:
And what about the oft-heard claim that philosophy, unlike science, makes no progress? As Bertrand Russell (himself no slouch at physics and mathematics) observed, philosophy aims at knowledge, and as soon as it obtains definite knowledge in a specific area, that area ceases to be called “philosophy.” And scientific progress gives philosophers more and more to do. Allow me to quote Nietzsche (although I know that will be considered by some to be in bad taste): “As the circle of science grows larger, it touches paradox at more places.” Physicists expand the circle, and philosophers help clear up the paradoxes. May both camps flourish.I don't find the Nietzsche quote disagreeable, but I find the invocation of Russell bizarre. Let a reader correct me on this, but I was under the impression that Russell thought that it was once a determinate method for solving problems had been figured out that those problems were jettisoned from philosophy and became science. Indeed, Russell's view seems to be that philosophy does not gain much in the way of distinct knowledge, and instead clears up conceptual muddles enough so that science can proceed. Like Russell and the logical positivists after him, I don't find much disagreeable in this attitude, but at the same time I'm not sure it does the sort of work Holt and other partisans of philosophy as a discipline need it to do.
[1] Weinberg's views were rendered more clear at an October 2012 conference on naturalism, available here, and Feynman's views of the relationship between philosophy and science are much more nuanced than often supposed. His more hostile comments about philosophers seem to be out of the same naturalistic polemical spirit as Hume's "commit it to the flames." See, for example, The Character of Physical Law and The Meaning of It All.
[2]For very different reasons, see Hume, Nietzsche, Wittgenstein, Kierkegaard, Marx...
[3]Feynman's The Character of Physical Law and The Meaning of It All, Weinberg's Dreams of a Final Theory, Bohr's Atomic Physics & Human Knowledge, all of Darwin's work, Lakoff and Johnson's Metaphors We Live By, etc.
[4]This is the source of my blog's title
[5]Penrose and Hawking's differences over the interpretation of QM are not merely realism and anti-realism, they have substantively different views of the physics. Hawking prefers Everettian interpretations, whilst Penrose dislikes them not because of his realism, but because as a strongly relativist (in the physical sense) critic of string theory, he thinks it can be shown that any successful quantization of gravity will have inevitable nonlinearities that make interpretations based on the unitary evolution of the wavefunction according to a linear version of the Schrödinger equation unnecessary. In this he could be said to fall under the umbrella of dynamical collapse interpretations.
His platonism about mathematics is important to his thoughts about computation and digital physics in particular. Penrose (rightly or wrongly) thinks advocates of various forms of computationalism (about physics, about the mind, etc.) underestimate the importance of the fact that the real numbers are continuous. Penrose claims that true continuity poses an insurmountable problem for computationalism. Penrose's argument basically goes:
- The real numbers are integral to our best physical theories
- The reals are continuous
- Mathematical entities have ontological status (platonism)
- From 3, the reals have ontological status
- From 2, 3, 4, continuity has ontological status
- If continuity has ontological status, then computationalism is false
- From 5, continuity has ontological status
- From 5, 6, computationalism is false
One can be a realist, nominalist, computationalist, so I don't think Penrose's platonism is directly relevant to how the realism/anti-realism debate impinges on QM.
No comments:
Post a Comment