2. Invariant Sensorimotor Features ("Affordances"). To say this is not to declare oneself a Gibsonian, whatever that means. It is merely to point out that what a sensorimotor system can do is determined by what can be extracted from its motor interactions with its sensory input. If you lack sonar sensors, then your sensorimotor system cannot do what a bat's can do, at least not without the help of instruments. Light stimulation affords color vision for those of us with the (...) right sensory apparatus, but not for those of us who are color-blind. The geometric fact that, when we move, the "shadows" cast on our retina by nearby objects move faster than the shadows of further objects means that, for those of us with normal vision, our visual input affords depth perception. From more complicated facts of projective and solid geometry it follows that a 3-dimensional shape, such as, say, a boomerang, can be recognized as being the same shape Ð and the same size Ð even though the size and shape of its shadow on our retinas changes as we move in relation to it or it moves in relation to us. Its shape is said to be invariant under these sensorimotor transformations, and our visual systems can detect and extract that invariance, and translate it into a visual constancy. So we keep seeing a boomerang of the same shape and size even though the shape and size of its retinal shadows keep changing. (shrink)

This is an introductory essay from The Interplay between Consciousness and Concepts, which I guest edited as a special double issue of the Journal of Consciousness Studies (vol. 14, Sept/Oct). It is also sold separately as a book by Imprint Academic. -/- -/- .

Ernst Cassirer claimed that Kant's notion of actual object presupposes the notion of truth. Therefore, Kant cannot define truth as the correspondence of a judgement with an actual object. In this paper, I discuss the relations between Kant's notions of truth, object, and actuality. I argue that's notion of actual object does not presuppose the notion of truth. I conclude that Kant can define truth as the correspondence of a judgement with an actual object.