Price on Quine again

This time around, Price splits the claims attributed to Quine into two:

1. Realism
2. Naturalism, that is, the claim that what is real is what we would be committed to by an ideal scientific theory, or, more immediately, what we have reason to think is real is what we are committed to by our best present scientific theories.

In a way that is by now familiar, Price argues that those who think Quine is a thick (real) realist have misunderstood him. This time, he concludes

1. Quine and Carnap are in complete agreement about the status of realism.
2. Quine denies the coherence of any ordinary–philosophical (internal–external) distinction.
3. Quine and Carnap disagree about the existence of standards for what we should accept as thinly real: Quine is a monist; he thinks there is a single standard—naturalism, but Carnap is a pluralist—he thinks we can accept multiple kinds of things as thinly real on various grounds.

He gives the so-called Quine-Putnam indispensability argument for the existence of mathematical objects as exemplifying the mistake. "The" argument is more or less as follows:

Our physical theories are, by and large, true.
Our physical theories, indispensably, quantify over mathematical objects.
Therefore, Mathematical objects exist.

There are two readings of the argument, as Price emphasizes: The thick realist reading takes it to be a genuine argument with an important conclusion. Since the argument is attributed to Quine, that exemplifies why so many have gotten Quine wrong. The thin reading is that there is not really an argument here at all, only a restatement of something implicit in the premises.

The thin version of the "argument" consists simply of noting that physical theories we take seriously make use mathematical objects. There is nothing more to it. The thick version, which is suggested by the form I put the argument in makes it look like there is a new stronger conclusion drawn on the basis of the premises. The only way to get that out of the argument is to implicitly supply something like the following:

1. Our physical theories make ordinary (thin, internal) use of the existence of mathematical objects.
   
2. Naturalism tells us that what is ordinarily required for physics is philosophically (really, externally) real.
   Therefore,

So, Quine thinks that, to the extent that there is a subject matter of ontology at all, it consists in producing coherent, precise versions of theories connected to physics. That will give us a single unified (monist) picture of what there (thinly) is.

Carnap thinks that, to the extent that there is a subject matter of ontology at all, it consists in producing coherent, precise, useful theories that we may be, in one sense or another, committed to. The physics has dropped out, and the unified notion of commitment has too. It is open, by Carnap's lights, to take mathematical objects to exist on mathematical grounds. Equally, it seems, we might end up with ontological commitments based on their utility for moral theory or aesthetics (or at least so Price thinks).

Price notes, quite correctly, that nothing Quine says in the debate about ontology provides any motivation for his naturalism. His monism is of a thin sort that is not incompatible with a kind of pluralism. He thinks that pluralism is superior because

• It avoids an unwarranted commitment built in at the beginning to some special things.
• If we do have reasons of fundamentally different kinds for accepting some different kinds of things, we can reflect that in our (thin) ontology. That will permit us to avoid category mistakes.

Quine does give an argument against the kind of pluralism Price defends, namely, holism: our reasons for accepting mathematics are intertwined with our reasons for accepting physics, and similarly for everything else. There just is no such thing a domain whose objects we accept for reasons that are independent of our reasons for accepting other domains. That is, the argument is Quine's holism.

He also has an argument for his naturalism, but it is complex and not directly related to our topics. It has to do with how language is used.

-- ShaughanLavine - 04 Dec 2008