Behavioral and Brain Sciences

Short Communication

Seeing, acting, and knowing

Zenon W. Pylyshyn a1
a1 Center for Cognitive Science, Rutgers University, New Brunswick, NJ 08854-8020 [email protected]


The target article proposes that visual experience arises when sensorimotor contingencies are exploited in perception. This novel analysis of visual experience fares no better than the other proposals that the article rightly dismisses, and for the same reasons. Extracting invariants may be needed for recognition, but it is neither necessary nor sufficient for having a visual experience. While the idea that vision involves the active extraction of sensorimotor invariants has merit, it does not replace the need for perceptual representations. Vision is not just for the immediate controlling of action; it is also for finding out about the world, from which inferences may be drawn and beliefs changed.