That “Back to Nietzsche” post set off a firefight (a philosophically friendly one, I hope), and one of the issues that came up has to do with the relation between naturalism and metaphysics.
“Naturalism” can mean many things, but one widespread meaning in philosophy is this: naturalism is the view that contemporary science is (roughly) right, leaving room open for future progress and changes, and there isn’t anything more to the world than what contemporary science discloses. (Again, this has to be understood in such a way as to allow for further developments in science that are continuous with it — like another kind of subatomic particle, further laws of nature, etc.) It is often linked up with materialism, though I really think “materialism” is losing its meaning. Naturalism takes as real stuff like matter, energy, forces and lines of force, probability distributions — anything that we can causally interact with, or (as Quine put it) anything that we have to quantify over when we put our understanding in its simplest expressions. (Quine said that “To be is to be the value of a bound variable” — how poetic!)
Now I understand that some philosophers object that there must be more to the world than naturalism claims. “More” could be souls, God, miracles, or final causes, intentionality, moral facts. And then the battle begins to see whether the naturalist can “explain away” the seeming presence of these things with the materials at hand. It is a battle I’ve been known to wage from time to time.
But in the end, my heart really isn’t in the battle, I guess because of the following line of thought. Working scientists chop away at the stuff they are trying to understand, predict, and explain. Never once do they say to themselves something like: “Damn! What we really need here is something from Aquinas!” and rush over to the Summa for some help. They just putter along, in relative philosophical ignorance, mapping the genome and making computers that play chess and creating new life forms and finding ways to get more crop production out of dirt and countless other amazing things.
Philosophers may complain: “There are so many metaphysical matters you scientists are ignoring or taking for granted!” But what does that show? To me it shows that metaphysics — at least as traditionally defined — doesn’t really matter when it comes to understanding the world. (Indeed, you could well argue that Galileo, Newton, and Einstein made progress precisely by ignoring metaphysical questions and sticking to measurement.) I just can’t bring myself to say, “You scientists, you think you understand the world, but you really don’t, unless you work out the metaphysics.” Any philosophical position which implies that philosophers have a better understanding of nature than scientists do seems to me plainly ridiculous. So, I say: so much the worse for traditional metaphysics.
“Metaphysics is dead! We have killed it!”
But why then am I a philosopher instead of a scientist? Because, in my view, a philosopher’s job is to try to put together a more global view of things than scientists can, in conjunction with philosophical concerns. Smashing atoms (or whatever) is a full-time job, and reading a mix of (more or less popularized) accounts of physics, biology, psychology, whatever, and asking philosophical questions about all the results, is a full-time job, so we need all kinds of people. It shouldn’t be a competition (science vs. philosophy), in my view, but a conjunctive effort. Some people advance knowledge, and other people try to piece it together and see what it means. I’d like to do more of this in the future: so far, I have limited myself mainly to the historical periods when doing philosophy was the primary way of gaining an understanding of the world! (Namely, before science gained its wings.) Philosophy is a handmaiden to science, I would admit.
All that being said, I do not want to insist that everyone should uncritically accept what scientists say. Some philosophers are raising intelligent objections to the stories scientists say, and that battle over science’s adequacy should continue. As I’ve said, my heart’s not in that battle, since no objection I’ve heard is as compelling to me as the prospect of a natural explanation for the phenomena in question; but if others want to argue over it, they should! And keep me posted. Heck, I’ll even join in from time to time!