What gives rise to the perception of motion?

The assumption that displacement of the retinal image over the retina is the basis for all perception of motion is rejected. The reasons for the plausibility of this assumption are considered. It is part of the traditional theory that retinal sensations are entailed in visual per-ception. But it involves a misconception of how the eyes work. An-other theory of the information for perceiving motion is proposed in terms of the ambient array of light. The registering of subjective bodily movements by vision is contrasted with the detecting of objec-tive environmental motions. A number of century-old puzzles are re-solved by this approach and a set of novel experiments is suggested. Experimental studies of the per-ception of motion in the past, especially of visual motion, have failed to resolve the old puzzles or to yield any kind of general explanation. The root of the