Directly perceiving Gibson: a further reply to Gyr.

Gyr (1972) forcefully criticized James Gibson's direct theory of perception. In his reply, Gibson (1973) argued that Gyr did not address two significant issues. The first is whether or not stimulus information (in Gibson's sense) exists, and the second is whether perception is based on stimulus information or on sensations. Gibson did not choose to correct several blatant misrepresentations of his position that provided the explicit foundation for Gyr's criticism. Since such misrepresentations appear to be common (e.g., Gregory, 1972; Haber & Hershenson, 1973, p. 335), it is important that they be corrected so that future discussion can be founded on substantial issues. The most glaring error in Gyr's caricature of Gibson's theory is the claim that Gibson believes stimulus structure can cause or determine what an organism perceives. For instance, Gyr interprets Gibson's position as one that maintains that "optic array information is sufficient for predicting a given perceptual process" (p. 248). This is the version of direct perception that Gyr criticizes. However it is not Gibson's version. Gibson does not believe that stimulus structure causes perception. He could not, for he believes that stimulus structure is indefinitely