5 A Theory of Direct Visual Perception

tual Systems (Gibson, 1966), especially in chapters 9–12 on vision. It is related to, although a considerable departure from, the theory presented in The Perception of the Visual World (Gibson, 1950). Some of its postulates go back 20 years to that book, but many are new. What is “direct” visual perception? I argue that the seeing of an environment by an observer existing in that environment is direct in that it is not mediated by visual sensations or sense data. The phenomenal visual world of surfaces, objects, and the ground under one’s feet is quite different from the phenomenal visual field of color–patches (Gibson, 1950, Ch. 3). I assert that the latter experience, the array of visual sensations, is not entailed in the former. Direct perception is not based on the having of sensations. The suggestion will be that it is based on the pickup of information. So far, all theories have assumed that the visual perception of a stable, unbounded, and permanent world can only be explained by a process of correcting or compensating for the unstable, bounded, and fleeting sensations coming to the brain from the retinal images. That is to say, all extant theories are sensation-based. But the theory here advanced assumes the existence of stable, unbounded, and permanent stimulus-information in the ambient optic array. And it supposes that the visual system can explore and detect this information. The theory is information-based, not sensation-based.