Marr’s Theory of Vision and the Argument From Success

Abstract

A central aspect of the computational theory of vision developed by Marr and his coworkers is the use made of contingent regularities in the physical environment to explain how the visual system determines the shape and location of objects in the world on the basis of the spatial organization of the retinal image. Marr (1982) refers to these environmental regularities as “natural constraints” and “physical assumptions.” In this paper I am concerned with recent arguments concerning the implications of this feature of Marr’s theory for understanding psychological explanation. Burge (1986) claims that Marr’s use of natural constraints shows the theory to be nonindividualistic, in the sense that the individuation of psychological states depends essentially on the objects and conditions of the world external to the subject. While it does capture an important aspect of Marr’s theory, Burge’s account is misleadingly incomplete. To see this it is useful to compare the issue of individualism with the question whether the theory is compatible with methodological solipsism as a research strategy.