The primary function of vision therefore is to construct a virtual-reality replica of the external world in an internal representation. This in turn highlights the constructive or generative function of perception identified by Gestalt theory, whereby the perceptual representation contains more explicit spatial information than the sensory stimulus on which it is based; a principle I have called reification.

A principal focus of psychology and neuroscience therefore should be to identify the operational principles behind the three-dimensional volumetric imaging system in the brain.