A Look Back at William James's
Theory of Perception
University of California, Berkeley
I cannot remember what my thoughts were when I first read William James's Principles of Psychology as a young student except that I admired the beautiful prose. On rereading it carefully now, however, I came away enormously impressed with James's grasp of the field of perception and with the feeling that we have not made the great strides in our knowledge about this field that might have been expected over a span of 100 years, particularly on a broad theoretical level. Others may disagree with this judgment. However, there have been some important discoveries and there has been some substantial progress in some areas.
What I propose to do in this chapter is first to review what James's theory of perception was, to comment about his theory in the light of presentday thinking, to discuss what we know now about perception that he did not, and finally to discuss one important idea James had about perceptual constancy that may well be right but which has been overlooked. I will end by asking the question about how much progress we have made in this field of inquiry in the 100 years since James Principles appeared.
Let us begin with a summary of James's theory of perception. To avoid distortion of his views, we will allow him to speak for himself as much as possible. We begin with definitions of sensation and perception:
"A pure sensation is an abstraction" (II: 3) and "in popular speech, and in Psychology also" the words sensation and perception "run into each other" (II: 1). Sensation . . . "differs from Perception only in the extreme simplicity of its object or content" (II: 2). "The nearer the object cognized