On C. D. Broad's theory of sensa

Abstract

C. D. Broad’s sensum-theory asserts that the objective constituents of perceptual situations—sensa—are never identical to the physical objects they represent. This non-identity thesis rests on the assumption that the characteristics of material bodies, such as persistence and three-dimensional extension, necessarily exclude the immediate data of awareness. However, phenomenological analysis informed by Gestalt psychology suggests that the directly perceived is experienced as a three-dimensionally closed whole rather than an indefinite patch, thereby challenging the categorical distinction between sensa and physical objects. The argument from delusive perceptual situations is flawed because internal similarities between veridical and hallucinatory states do not logically preclude the presence of a physical constituent in veridical cases. Furthermore, the argument from continuity is weakened by the psychological phenomena of size and shape constancy; these demonstrate that perceptual impressions do not vary in strict proportion to retinal changes, making the transition between perceived appearances and physical properties a matter of vagueness rather than a proof of non-identity. Additionally, the finite velocity of light fails to decisively separate the sensum from the object, as temporal intervals are often negligible within the specious present and do not account for the potential persistence of sensa. Therefore, the primary philosophical and empirical justifications for the non-identity of sensa and physical objects are inconclusive. – AI-generated abstract.