Originally I had thought I’d break a long post into two parts, but then I got carried away. So this ended up as a kind of online note-taking and thinking out loud prompted by some recent books I’ve read. Oh well, here goes again…

I’ve said I’m partial to the idea of rehabilitating metaphysics, bringing it out of the realm of armchair reflection and Platonic rationalism and seeing how it might play a role in systems that make contact with reality tests. There is, I think, another advantage to doing this. We can thereby assimilate rehabilitated metaphysical claims to the more innocent and unavoidable existence claims we find in science and in everyday life.

One motivation for a return to metaphysics seems to have been a realization that scientific theories include catalogs of objects that are supposed to exist and behave in certain ways. The existence of these objects does genuine explanatory work, even if they are not directly observable. For example, according to quantum chromodynamics, we cannot detect unconfined quarks. This doesn’t greatly bother physicists, and we generally think quarks are quite real. (Though interestingly, physicists will also shy away from claiming things are real in contexts where “real” stands for some metaphysical Realness.)

I can be tempted, in an antimetaphysical mood, to flirt with instrumentalism, saying that such objects are convenient fictions. But that would be overdoing things. It invites questions such as whether ordinary rocks are also convenient fictions. Moreover, in the name of opposing metaphysics, instrumentalists might be introducing a disguised idealist or dualist metaphysics, making everything real happen in the observing mind. We should avoid taking commonsense views of observation and mind as givens.

It is better, I think, to accept that existence claims in everyday and scientific contexts are innocuous. In any case, such claims tread much more lightly than claims about metaphysical insight into Ultimate Reality. In physics, for example, we can take particles or fields to be the more fundamental entities in the context of our present theories. But the difference here is a matter of emphasis and conceptual clarity; particles and fields are inseparable however we choose our emphasis. And if, in the future, we end up adopting a different description of the basic furniture of the universe according to physics, we will do this because of the usual mutual interaction between theory and experiment that fixes belief in physics, not because of some kind of metaphysical reflection.

Now, if we rehabilitate metaphysical naturalism by using this more innocuous kind of existence claims, we can get a fallible, broadly scientific claim about the nature of our world. Instead of being a metaphysical doctrine in the classic sense, naturalism becomes akin to an ambitious scientific theory with very broad scope.

Consider physicalism, perhaps the most uncompromising version of naturalism available. The kind of physicalism I am partial to is, I think, a broadly scientific theory rather than a metaphysical doctrine. Andrew Melnyck’s “realization physicalism” is along these lines, and I largely agree with Melnyk. Moreover, mounting another of my hobbyhorses, I like to argue that physical explanations that combine chance and necessity suffice to describe all we know in the world, including intelligence and so forth. There is no need to make claims about Ultimate Reality in any of this—only ambitious claims analogous to the way physicists expect the known laws of physics to apply everywhere in the universe and make predictions based on this expectation. Saying that we can best understand the world without supernatural or transcendent realities is not radically different from claiming that we can do biology better without postulating the existence of animal spirits or life forces.

Emphasizing on natural science as a model of avoiding metaphysics is bound to raise questions about scientism. Doesn’t this ignore realms of genuine knowledge where Platonic metaphysics is legitimate, such as mathematics? Aren’t I pushed toward assimilating everything into some scientific method, even discourses such as ethics and possibly religion? I’ll try to get to these next, though I really have to figure out how to stop this before I find myself typing part 58.