It is to Brunswik’s credit to have formulated the most articulate description of what must take place in the perceptual process. That this description is veridical seems to be indicated by the fact that it is independent of existing psychological theories and of epistemological postulates as to how man knows what he knows or as to what science is. It seems difficult to conceive that this description will be found to be incorrect in the future, though, of course, it is to be expected that with the increase of factual knowledge and conceptual sophistication many additional details may be added to it. The power of this descrip tion is such that it can be used to develop a chain of thought that is in many ways in opposition to Brunswik’s assumptions concerning knowledge and science. Such a development will be attempted in this paper.