 One function of this relation is to make objects present in such a way that they can shape or mould the character of one’s experience. In virtue of this, perceptions of the world are unlike (non-perceptual) thoughts about the world: they are constrained by the objects actually given. One’s perception of a snow-covered churchyard is responsive to how the churchyard is now, as one is perceiving it. But one’s (non-perceptual) thought need not be: in the middle of winter, one can imagine the churchyard as it is in spring, and one can think of it in all sorts of ways which are not the ways it presently is.