If, however, MOPS are in the head,16 then they can be proximal mental causes and are, to that extent, apt for functional individuation. If MOPs are both in the head and functionally individuated, then a MOP’s identity can be constituted by whathappens when you entertain it.11 And if the identity of a MOP is constituted by what happens when you entertain it, then ofcourse there is only one way to entertain each MOP. In point of metaphysical necessity, the alleged ‘different ways ofentertaining a MOP’ would really be ways of entertaining different MOPs.
The moral, to repeat, is that even Frege can’t have 5.3 if he holds onto 5.1. Even Frege should have been a mentalist about MOPs if he wished to remain in other respects a Fregean. On the other hand (perhaps this goes without saying),to claim that MOPs must be mental objects is quite compatible with also claiming that they are abstract objects, and thatabstract objects are not mental. The apparent tension is reconciled by taking MOPS-qua-things-in-the-head to be thetokens of which MOPS-qua-abstract-objects are the types. It seems that Frege thought that if meanings can be sharedit somehow follows that they can’t also be
In this usage, an ‘externalist’ is somebody who says that ‘entertaining’ relates a creature to something mind-independent, so Frege’s externalism is entailed by his Platonism. Contrast the prima facie quite different Putnam/Kripke notion, in which an externalist is somebody who says that what you are thinking depends on what world you’re in.(Cf. Preti 1992, where the distinction between these notions of externalism is sorted out, and some of the relations between them are explored.)
This way of talking is, of course, entirely compatible with the current fashions in Individualism, Twins, and the like. Twins are supposed to show that referents can distinguish concepts whose causal roles are the same. For the demonstration to work, however, you’ve got to assume that Twins ipso facto have the causal roles of theirconcepts in common; viz. that whatever contents may supervene on, what causal roles supervene on is inside the head. That’s precisely what I’m supposing in the text.
Notice that this is not to say that concepts are individuated by the mental processes they cause, since a concept is a MOP together with a content; and I’ve taken an informational view of the individuation of contents. It‘s thus open to my version of RTM that ‘Twin-Earth’ cases involve concepts with different contents but the sameMOPs.
particulars. But it beats me why he thought so. You might as well argue from ‘being a vertebrate is a universal’ to ‘spines aren’t things’.
We’re almost through with this, but I do want to tell you about an illuminating remark that Ernie Sosa once made to me. I had mentioned to Ernie that I was worried about why, though there are lots of ways to grasp a referent, there’sonly one way to grasp a MOP. He proceeded to pooh-pooh my worry along the following lines. “Look,” he said, “it’spretty clear that there is only one way to instantiate a property, viz. by having it. It couldn’t be, for example, that theproperty red is instantiated sometimes by a thing’s being red and sometimes by a thing’s being green. I don’t supposethat worries you much?” (I agreed that it hadn’t been losing me sleep.) “Well,” he continued, with a subtle smile, “ifyouaren’t worried about there being only one way to instantiate a property, why are you worried about there being only one way to grasp a modeofpresentation?’”
I think that’s very clever, but I don’t think it will do. The difference is this: It is surely plausible on the face of it that ‘instantiating property P is just being P; being red is all that there is to instantiating redness. But MOP is a technicalnotion in want of a metaphysics. If, as seems likely, the identity of a mental state turns on its causal role, then if MOPsare to individuate mental states they will have to be the sorts of things that the causal role of a mental state can turn on.But it’s a mystery how a MOP could be that sort of thing if MOPs aren’t in the head.Jean-marc pizano