Jim Gibson

For centuries psychologists have been trying to explain how a man or an animal could perceive space. They have thought of space as having three dimensions and the difficulty was how an observer could see the third dimension. For depth, as Bishop Berkeley asserted at the outset of the New Theory of Vision (1709), “is a line endwise to the eye which projects only one point in the fund of the eye.” Space was its dimensions. It was empty save for a collection of objects or bodies. For an observer, the objects were in different directions at various distances and the question was how these distances could be detected. For two hundred and fifty years we have tried to answer this question and failed. The explanations have been controversial, contradictory, and confused.

This is a book about how we see: the environment around us (its surfaces, their layout, and their colors and textures); where we are in the environment; whether or not we are moving and, if we are, where we are going; what things are good for; how to do things (to thread a needle or drive an automobile); or why things look as they do.The basic assumption is that vision depends on the eye which is connected to the brain. The author suggests that natural vision depends on the eyes in the head on a body supported by the ground, the brain being only the central organ of a complete visual system. When no constraints are put on the visual system, people look around, walk up to something interesting and move around it so as to see it from all sides, and go from one vista to another. That is natural vision—and what this book is about.

Both the psychology of perception and the philosophy of perception seem to show a new face when the process is considered at its own level, distinct from that of sensation. Unfamiliar conceptions in physics, anatomy, physiology, psychology, and phenomenology are required to clarify the separation and make it plausible. But there have been so many dead ends in the effort to solve the theoretical problems of perception that radical proposals may now be acceptable. Scientists are often more conservative than philosophers of science. I end, therefore, as I began, with a plea for help