Semantics and Uniqueness

For a while I've been thinking that I'm stuck between the two poles of Plato and Wittgenstein, although on some days I'm better at explaining what that means exactly than on others. Today in Epistemology we chewed over an inchoate idea that floated through my mind yesterday. (Wilbert Munoz pointed out that we were talking about metaphysics more than epistemology, which was true enough, but we got there honestly: we've been thinking about Nagel's attempt in The View From Nowhere to establish some way of talking about subjectivity as something in the world, and I'm pretty sure that Wittgenstein is right (contra Nagel) that this is not possible.)
Anyway, the half-baked ("inchoate" is a fancy-pants way of saying half-baked) idea was this: Wittgenstein argues that the semantics of all language is necessarily grounded in public, intersubjective referents, and that this extends to psychological ("phenomenological") terms (for example in the "beetle-in-a-box" passage). Meanwhile Plato seems committed to the view that any description of a particular is necessarily in terms of properties, and thus descriptions are composed of assignments to categories (I guess Aristotle thinks this too, although they have opposite accounts of primary being). If some particular had a property that was unique to that particular, could we name it? I have the feeling that the answer is going to have to be "no." So, the connection: the Cartesian claims that the taste-of-chocolate-for-me is a real element in the world, one that only I can know about etc. Wittgenstein counters that we can only talk about plain old taste of chocolate. Is the putative (or possible) uniqueness of the taste-for-me what precludes the possibility of meaningful reference to it? And does this reveal an unexpected similarity between Plato and Wittgenstein, inasmuch as both think that reference amounts to a kind of categorization? Just an inchoate note, I have to go make some photocopies for 11:30 class.