The “Tuesday’s talk” thread was getting a bit long, so I thought I’d create this post where the discussion can continue further.
Kleiner posted this note:
“Do you think empirical science has to have a materialism metaphysics? I don’t think it does. In fact Aquinas makes arguments that begin (but do not always end) with empirical data. I would argue that without something immaterial, science (or any kind of intelligibility) is impossible (see recent Machuga lecture).
“In short, what I resist is your tendency toward reductionism. Moving from the claim that the body matters to full blown materialism. Moving from science to scientism. I just don’t see any real justification for these moves. In fact, making those moves undercuts your science. I think Hume is right, if you are going to restrict yourself to nothing other than empirical data, then you cannot even justify science (causation).”
No, I don’t think an empiricist has to be a materialist, George Berkeley and Ernst Mach were empiricists, and idealists. But that’s not what Kleiner has in mind, I think. He and Machuga really have in mind an argument between nominalists and realists.
The nominalist believes particular things (whether atoms, bodies, or simple ideas) are real, and all general things (concept of “DOG”, concept of “MASS”) somehow “ride upon” (supervene) upon the particular things. These general things are sometimes called “universals.”
The realist, on the other hand, thinks that these general things must be real. If they weren’t real, then there would be nothing in virtue of which all the particular dogs come to be correctly classified under the concept “DOG.” This might not sound compelling in the case of dogs, so here’s a more gripping example. Sceintists end up talking about kinds of things, like hydrogen. Well, what makes it true that this little bitty thing and that little bitty thing are both hydrogen atoms? “They have the same structure,” we answer. “Same structure”? Isn’t that just to say there is a thing (same structure) those two particular little bitty things have in common? That’s a universal, folks.
The realist then continues: universals, by definition, aren’t particular things. But every material thing is a particular thing. (Try to name one that isn’t!) So does it not follow that there exist immaterial things? And as a follow up: If we can somehow perceive or pick up on the existence of these immaterial things, then how can we be purely material beings?
(How’s that, Kleiner?)
My own answer — well, let me try this out as an answer, and see what happens — is that the question “is it material?” simply does not apply to universals like structure or function. It’s sort of like taking an adjective, verb, or adverb and asking what thing it refers to. Those parts of speech don’t refer to things; they’re not like nouns. They describe what things do, or what they are like. So the universal “DOG” actually is the property or cluster of properties dogs have in common. And if someone asks, “Is that universal material?” I want to answer, “No, but neither is it immaterial. It’s not a thing. It’s a property.” It’s tricky here because we can easily start talking about properties as if they are things — thus turning adjectives into nouns — and then start thinking that names of properties name things (i.e., universals). But we’re being misled by grammar.