The classical theories of perception assume that the flux of stimulation causes a flux of sensation, the basis of perception, and that the perception of permanent objects must somehow be constructed from this flux. Accretion yielded the perception of surface-being-revealed and deletion the perception of surface-being-concealed, i.e., going-behind and coming-from-behind. The most cogent examples of the phenomenal persistence of objects and surfaces despite the non-persistence of their sensations are of the sort. The motion of a persisting object or animal in the environment causes a local disturbance in the ambient array, a change in the perspective of the object. On the basis of color patches alone it would be impossible to distinguish between the moving observer, the moving object, looking around, and the genuine non-persisting object.