Leading theorists have, since the beginning of philosophy, been involved in formulating theories about the relationship between mental processes and the physical world, and to what extent they affect each other. There has been considerable debate over the relationship between the two and the issue is yet to be solved. All authorities, however, agree that understanding the processes of vision is a key to understanding the wider cognitive processes. The two works under study, Gregory's Eye and Brain and Dodwell's Fundamental Processes in Vision provide an in-depth look into the psychology of vision by two of the most eminent scholars of this field. Both the authors, Gregory and Dodwell, counter this issue with their own particular points of view, which are at times in accord and at others in discord with each other. Needless to say, since both the writers are considered authorities in the field of psychology, they use various sources to support their claims. This paper aims to look at the effectiveness of the pictorial illustrations used by either of them in supporting their respective claims regarding mind and matter.
Gregory believes that the study of illusions is the key to understanding the fundamentals of vision because " physiological illusions tell us about brain, and cognitive illusions about mind. (This, if we think of mind as the brain's knowledge and hypothesis-generating rules and intelligence.)" (Gregory 248). He therefore focuses a great deal on different forms of illusions, their classifications and their possible interpretations in chapter 10, and in a great portion of the concluding chapter 11. Dodwell takes a slightly different position than Gregory in this case. Even though he explicitly agrees that the study of illusions is a major component in agreeing the complexity of the processes of vision, he maintains that the field is too large and complicated to be understood by taking a single viewpoint.