Some materialists, however, seek to evade this difficulty by suggesting that there is some sort of logical connection between physical states and mental states. It is a logically necessary truth, they say, that when a given physical state occurs, a certain mental state also occurs. If this is true, then the existence of the mental is certainly probable, given our physical world; indeed, its existence is necessary. Nagel himself suggests that there are such necessary connections. So wouldn’t that be enough to make intelligible the occurrence of the mental in our physical world?Does Alvin Plantinga think that he can "just see" the truth of the arithmetic equality he states? If so, could he please enlighten the rest of us as to just what kind of sense-objects the numbers 1, 2, and 3 are? If a number is a class of all objects which are in bijection with one another, as Frege proposed, what is +? If a number is a hereditary set -- an "object" of pure imagination, how can Plantinga see or sense any such relationship?
I suspect that his answer would be no. Perhaps the reason would be that we cannot just see these alleged necessities, in the way we can just see that 2+1=3.
It is disappointing when a scholar gives such free and open rein to his biases and preconceptions, without even a token nod at the methodological difficulties which others have made entire careers of.