Jean-marc pizano etc. depending on what intentional relation the reasoner bears to it, depending, if you like, on how thereasoner entertains it. In this sort of case, then, lots of concepts correspond to the same mode of presentation. Or,putting it the other way round, what corresponds to the reasoner’s concept is not the mode of presentation per se, butthe mode of presen tation together with how it is entertained.
A diagram can be used in all sorts of ways to present things to thought, but a Fregean sense can’t be on pain of senses failing to individuate concepts, which is, after all, what they were invoked for in the first place. So,
question: what stops senses from behaving like diagrams? What guarantees that each sense can serve in only one way to present an object to a thought? I think that, on the Frege architecture with 5.3 in force, nothing prevents this exceptbrute stipulation.
As far as I know, the standard discussions have pretty generally failed to recognize that Frege’s architecture has this problem, so let me try once more to make clear just what the problem is. It’s because there is more than one way tothink about a referent that Frege needs to invoke MOPs to individuate concepts; referents can’t individuate conceptsbecause lots of different concepts can have the same referent. Fine. But Frege holds that MOPs can individuateconcepts; that’s what MOPs are for. So he mustn’t allow that different MOPs can correspond to the same concept, normay he allow that a MOP can correspond to a concept in more than one way. If he did, then each way of entertaining the MOPwould (presumably) correspond to a different way of thinking the referent, and hence (presumably) to a differentconcept of the referent. Whereas MOPs are supposed to correspond to concepts one-to-one.
So, the question that I’m wanting to commend to you is: what, if anything, supports the prohibition against proliferating ways of grasping MOPs? Frege’s story can’t be: ‘There is only one way of thinking a referentcorresponding to each mode of presentation of the referent because there is only one way of entertaining each mode ofpresentation of a referent; and there is only one way of entertaining each mode of presentation of a referent because Isay that’s all there is.’ Frege needs something that can both present referents to thought and individuate thoughts-, in effect,he needs a kind of MOP that is guaranteed to have only one handle. He can’t, however, get one just by wanting it; he hasto explain how there could be such things. And 5.3 is in his way.
I think that if MOPs can individuate concepts and referents can‘t, that must be because MOPs are mental objects and referents aren’t. Mental objects are ipso facto available to be proximal causes of mental processes; and it’s plausible thatat least some mental objects are distinguished by the kinds of mental processes that they cause; i.e. they are functionallydistinguished.14 Suppose that MOPs are in fact so distinguished. Then it’s hardly surprising that there is only one way amind can entertain each MOP: since, on this ontological assumption, functionally equivalent MOPs are ipso factoidentical, the question ‘Which MOP are you
This doesn’t, please notice, commit me to holding that the individuation of thought content is functional. Roughly, that depends on whether Frege is right that whatever can distinguish coextensive concepts is ipso facto the sense of the concepts; i.e. it depends on assuming 5.1. Which, however, I don’t; see above.
entertaining?’ and the question ‘Which functional state is your mind in when you entertain it?’ are required to get the same answer.
Frege’s structural problem is that, though he wants to be an externalist about MOPs, the architecture of his theory won’t let him.15 Frege’s reason for wanting to be an externalist about MOPs is that he thinks, quite wrongly, that if MOPs aremental then concepts won’t turn out to be public. But if MOPs aren’t mental, what kind of thing could they be such thatnecessarily for each MOP there is only one way in which a mind can entertain it? (And/or: what kind of mental statecould entertaining a MOP be such that necessarily there is only one way to entertain each MOP?) As far as I can tell,Frege’s story offers nothing at all to scratch this itch with.