The blurring of the boundary adversely affects the 'second' part of Hobbes's physics. After offering a general account of sense or sentience, he turns in the last Part of De Corpore to an account of the 'objects' of sense. He wants to show that the sensible qualities, by which we register differences between external bodies, are not qualities intrinsic to the bodies, but effects of their interactions with our sense-organs. The properties external bodies have to possess intrinsically in order to appear as they do, turn out not to be exactly the properties we experience them as having. Certain of their apparent properties are merely apparent, contributed to our phantasms not by what they are like, but by the way we are physiologically constituted to respond to the motions they impart. That the sensible qualities are somehow subjective is one of the main claims of Hobbes's physics, and in a sense the claim is right. There is an important subjective/objective distinction to be drawn in this area, but, as we shall see, not the one Hobbes calls attention to. His distinction, between phantasms in the sentient and accidents of bodies, is no less unstable than his distinction between matter that is animate and matter that is not.