So, I'm taking a course in contemporary metaphysics this term, and I feel a bit like I've wandered into a foreign land of nonsense and speculation. For the most part, I am interested in the history of philosophy or philosophy of science and so my study of philosophy has to this point been fairly bereft of bizarre arguments about possible worlds, multiple realization, and some of the other arcane theoretical entities and relations that stalk the pages of philosophy journals.
I think I prefer it that way. We're into week 3 on "supervenience" and I still have no idea what that term is supposed to mean. The slogan version is simple enough: if property A "supervenes" on property B, then any two entities that are exactly the same in respect to their B-properties will be identical in respect of their A-properties. If mental properties supervene on neurophysiological properties, then any two identical brains will have identical thoughts.
Ok. So far, so good. The problem comes when you try to say anything further. Saying that mental properties supervene on neurophysiological properties doesn't tell us much at all about either set of properties, and it tells us absolutely nothing about the relation between the two sets of properties.
The way I read it, a supervenience claim is either an uninformative claim that the two sets of properties show covariance or an incomplete claim that one set of properties depends on the other. Either way, just saying that A supervenes on B is not saying much.
Maybe I don't really understand the philosophical import of this notion. Let's hope so, because otherwise it's going to be a long quarter.