 However Descartes, by endorsing that argument, does not endorse the claim that ‘if I can conceive of A’s existing without B’s existing, then A can exist without B existing’. He endorses at most the weaker claim that ‘if I can clearly and distinctly conceive of A’s existing without B existing, then A can exist without B existing’. There’s a special sort of conceivability involved here, clear and distinct conceivability, which licenses the move in this case but not in general. Hobbes’s argument seems blind to this distinction.