Wednesday, July 05, 2006

More on Dorr

Dorr is interested in how nominalists can account for the necessity of the claim:

(D) Whenever x is an electron, and y is a duplicate of x (or y is qualitively indiscernible from x, if you think that being a electron is non-intrinsic) then y is an electron.

He first discusses what he calls the physical strategy. The idea is that a science adequate to completely describe the actual world will provide us with the resources to give a real definition of 'duplicate':

(P) For x to be a duplicate of y is for it to be the case that x is an electron iff y is an electron, and x is a quark iff y is a quark, etc...

Unsurprisingly, this suggestion is deemed implausible, since it ignores the possibility of things being duplicates in virtue of sharing alien properties (nominalistically construed, obviously).

What surprised me was that Dorr suggested that our very own Joseph Melia might be a proponent of the physical strategy. This isn't how I understand Joseph's position, and is fairly straightforwardly and obviously inconsistent with the appeals to the possibility of alien properties that he and Divers make in the Analytic Limits paper, etc, so I was interested in why Dorr might have come to think this. I guess he must be going on the remarks on p 8 of Joseph's Truthmaking paper, where he talks about fundamental science being incomplete. Before that he has given solely actual world examples ('charged', 'square', 'mass'), but then, it is pretty hard to give examples of particular alien properties. And he seems to be restricting discussion to moderately sparse properties. But I don't see anything to motivate the idea that there is an implicit restriction to actually instantiated properties. On the contrary, Joe seems often to be pressing the idea that the sensible nominalist should be happy if he can establish that we can see how a certain sentence might be made true, or how the world could be a certain way in virtue of certain of its more fundamental aspects (e.g. why "it could have been the case that there were sets of duplicate objects that were ways that no actual things are" is true) without there being universals, even though we can't actually give a nominalistic paraphrase of the sentence. (This is something that Dorr himself seems to be happy with - he only requires 'paraphrase in principle', though one wonders whether even that may be too strong). That idea obviously carries over neatly to the aliens case. Once we see what is the truth of the sentences about non-alien duplicates consist in, it's not difficult to get a sense of what is explaining the truth of sentences about alien duplicates. And nothing which is illegitimate by the nominalist's lights seems to need brought in.

If it is the remarks on page 8 that is motivating Dorr's characterisation, I think that's a misreading. All Joe seems to be doing there is motivating the idea that we can recognise good truthmaker explanations even in the absence of paraphrase. That's something that ought to carry over very straightforwardly to the aliens case. Dorr notes that there have been 'few explicit defences' of the physical strategy, but suggests despite this, it is quite popular. I think it might be at least a little less popular than he suggests.


Robbie Williams said...

Here's one thing that came up at the seminar on the paper. In Joseph's way of looking of things (I believe) there's a clean distinction between two projects: conceptual analysis as traditionally construed (so we're in the market e.g. for something in the region of synonymy, and systematicity, being constraints on success); and metaphysics proper. On the metaphysics side, lots of constraints are off: in particular, when we're thinking about the underlying metaphysics of "A and B are of the same colour" we might cite A's being green and B's being green (this then connects up with truthmaker stuff).

Now, Dorr uses the term "analysis" (or "metaphysical analysis") for something rather more unconstrained than conceptual analysis as traditionally construed. E.g. infinitely long sentences can be the analysans of an ordinary sentence, it appears (he raises this explicitly in footnote 32, and another way it might arise for him is if theories of abstract objects aren't finitely axiomatisable). And "being made of H20" can be the analysans of "being made of water"

But some constraints are left on, in comparison with Joe's "metaphysics proper". E.g. it looks like for Dorr the metaphysical analysans is required to be necessarily eqivalent to the metaphysical analysandum. That would immediately rule out offering "A's being green and B's being green" as an analysis of "A and B being of the same colour".

So I guess one challenge to Dorr from Joseph's stuff is this: given you've given up the ambition of analysis traditionally construed, why think that there's a project of "metaphysical analysis", "intermediate" between conceptual analysis and unconstrained metaphysics?

andrew said...

Apologies to all for the no-show on Friday. Life intervened...

In Dorr's Oxford Studies paper 'Non-symmetric relations' - the one we looked at last year - he says a little more about the relevant notion of analysis. He takes understanding the ultimate structure of reality as one of the key aims of metaphysics. He wants to take this as equivalent to the quest for a complete list of primitive predicates. Primitive means unanalysable, but taking the relevant notion of analysis to be conceptual lets in far too much, given a moderate scepticism about the prospects for conceptual analysis. So analysis in the relevant sense is construed as closer to 'real definition', exemplified by the familiar kinds of a posteriori property identities.

I'd probably get off the boat with the identification of grasp of the ultimate structure of reality with the provision of a list of primitive predicates. (Again, Joseph's stuff on predicates v operators is to the point here.) But even if we grant this, it looks like the property identity analogy - which will, plausibly, involve providing intensional equivalents - may be a misleading way of spelling out the relevant notion of primitiveness. Why should understanding what's ultimate or fundamental in nature entail the provision of property identities (or claims regarding what-it-is-to-be the property) rather than just identifying the the way that the world is in virtue of which every other way the world is, is? We can say that a given object x is coloured in virtue of its being green without saying that what it is to be coloured is to be green.