Physics and philosophy: a civil and enlightening discussion

So, more on physics and philosophy:  this discussion thread involving Wayne Myrvold, Vishnya Maudlin, and Matthew Leifer is a model of civil discussion in which it looks like mutual understanding is increased, and that should be enlightening, or at least clarifying, to "listeners".  Matthew makes a point I made in my previous post:

Matthew Leifer [...] Wayne, I disagree with you that studying the foundations of quantum theory is philosophy. It is physics, it is just that most physicists do not realize that it is physics yet. Of course, there are some questions of a more philosophical nature, but I would argue that the most fertile areas are those which are not obviously purely philosophy.

Wayne Myrvold (June 12 at 6:42am)

Ah, but Matt, but part of the main point of the post was that we shouldn’t worry too much about where we draw the boundaries between disciplines. It’s natural philosophy in the sense of Newton, not counted as physics by many physicists, and may one day will be regarded as clearly part of physics by the physics community—- does it really matter what we call it? [...]

Matthew's response: "Well, it matters a lot on a personal level if you are trying to get a job doing foundations of quantum theory in a physics department 🙂 More seriously, I think there is a distinction to be made between studying the foundations of a theory in order to better comprehend the theory as it presently exists and studying them in order to arrive at the next theory."

Matthew puts a smiley face on the first sentence, and continues "More seriously..." But I think this is more serious than he is letting on here. In my view, thinking about M-theory and string theory and thinking about the foundations of quantum theory are roughly evenly matched as far as their likelihood (by which I mean probability) of giving rise to genuine progress in our understanding of the world (I'd give quantum foundations the advantage by about a factor of 10.) In fact, thinking about quantum foundations led David Deutsch to come up with what is pretty much our present concept of universal quantum computation. Yet you basically can't do it in a US physics department without spending much of your time on something else in order to get tenure. This is part of why I'm not just annoyed, but more like outraged, when I read pronouncements like Hawking's about philosophy being dead.

As with Wayne's post on which this thread comments, I thank Matthew Leifer for the link to this thread. Do read the whole thing if you find this topic area at all interesting as there are several other excellent and clearly expressed insights in it.

Myrvold on philosophy of physics and Hawking and Mlodinow

Since Hawking and Mlodinow's book "The Grand Design" (I keeping wanting to type "The Grand Illusion") is from 2010 (the stack of new copies I saw in the Harvard bookstore must have been remainders), there has, of course, been plenty of discussion of the "philosophy is dead" claim in the blogosphere.  Matthew Leifer kindly pointed me to a post by philosopher Wayne Myrvold in which Wayne tries to find what is reasonable in H & M's claim.  "The quest for the sorts of knowledge that Hawking and Mlodinow are talking has passed from people called philosophers to people called scientists, not because one group failed and had to pass on the torch, but because we started calling that quest “science,” rather than philosophy."  This is partly true, and my mention of "natural philosophy" was meant in part to allude to this, but let's look at the questions H&M pose again: "How can we understand the world in which we find ourselves?  How does the universe behave? What is the nature of reality?  Where did all this come from?  Did the universe need a creator?"  Inasmuch as philosophy of science is still a philosophical discipline, and not a part of science itself, the first question is still a major concern of what we call philosophy, even if scientists, obviously, have to address it at least tacitly because understanding the world is part of what they do.  As for the nature of reality, I suppose that depends in part upon what's meant by "the nature of reality".  But again, this is still a major concern of philosophy, even, perhaps especially, when reality is considered in its scientific aspect. What does it mean to say that the entities mentioned in scientific theories are real, when the theories they appear in get replaced by other theories, in which sometimes the old entities don't appear? It may be that physics will henceforth proveable to handle such questions with litle input from philosophers, but I don't think this is guaranteed. Inasmuch as science addresses the other two questions, about "where it all came from" and the existence of a creator, I also suspect that the broad point of view, and experience in the subtleties of the relevant concepts, of "analytic" philosophy, is still a valuable complement to science.  And then there are all the other questions that philosophy addresses.

Later, Myrvold says:

My own work consists, in part, of addressing the question, “What is the empirical success of quantum theory telling us about the world?”  This is a question that physicists don’t have to ask.  Much of the work done by physicists can proceed without an answer to this question.  Moreover, a case can be made, I think, that there have been moments in the development of quantum mechanics when progress was made by setting aside this question, at least temporarily.  But they can ask this question, and many of them do.  When they do so, they are engaged in philosophy of physics.

I guess physicists don't have to ask this, but many of them do. Plenty of scientists, in fact, think science is about finding out how the world is, beyond mere "empirical success". How "the way the world is" relates to "empirical success" is of course a classic philosophical question. But I think that often, when philosophers work on the question of what quantum theory tells us about the world, they are doing physics. This doesn't necessarily imply that Wayne is wrong that the physicists who ask that question are doing philosophy of physics. I take it rather to imply that this is where the unity of human thought that is suggested by terminology like calling science "natural philosophy" is evident. As I said in my first post on this subject, the people currently called "philosophers" have something to contribute, along with those called "physicists" and, perhaps especially, those who don't necessarily care what they are called.

I should point out that Wayne has a lot of good stuff to say following the paragraph I quoted, and I recommend reading it. (That's not to say I agree with all of it, of course.)