New Theory of Vision: Heterogeneity

Abstract

In the texts thus far examined Berkeley rejects the ‘optical angle’ theory of distance perception. By way of proof, he introduces the case of the man-born-blind-made-to-see. This thought-experiment is taken to establish that there is no necessary relation between the data of sight and touch. Indeed it is held that there is a real and radical separation. Extension as seen is not the same as tactual extension. Visual extension is inseparable from colour, and colour it is agreed is ‘not without the mind’. The data of touch and sight can be thought of as minima visibilia’and tangibilia, the ultimate constituents of each portion of our sensory experience. In a few short pages Berkeley ranges over a number of difficult issues, but he makes it clear that a central concern is the analysis of extension.