FROM CONCEIVABILITY TO POSSIBILITY An Essay in Modal Epistemology

This study deals with the thesis that conceivability implies possibility. Confronted with alleged counterexamples to this thesis, some philosophers have turned to what may be called “idealized” or “more demanding” notions of conceivability. I argue that in turning to such notions, they have made the thesis useless to limited beings like us for attaining modal knowledge. However, in refusing to identify conceivability with demanding or idealized notions, we cannot maintain that conceivability always implies possibility. Essentially, there are two ways to proceed: to view conceivability as a mere guide to possibility, or to argue that the conceivability thesis is a local truth, i.e., a truth with respect to a certain class of statements. I defend the latter alternative. This class of statements employs concepts with respect to which doubt concerning the conceivability thesis is to be regarded as general skepticism, not as skepticism relating to the conceivability thesis itself. I proceed by outlining an interpretation of strict possibility—i.e., the kind of possibility that I take the conceivability thesis to be about—according to which modal truths depend essentially on conceptual relations, as opposed to obtaining purely in virtue of properties of things themselves. Given this account, on which both ideal conceivability and strict possibility have a conceptual ground, I argue that these notions are not only coextensional but relate to one and the same property of statements. I further argue that the impossible is unimaginable, but that it is conceivable in the sense that one can misdescribe the contents of imagination.