Research Group
in Analytic Philosophy

Abstract

Direct realism is the thesis that in veridical cases we directly experience external material objects, without the mediation of either sense-data or adverbial contents. A well-known argument against direct realism, originally developed by Bertrand Russell, is the time lag argument, i.e. the argument stressing that light travels at a finite speed and a time separation exists between the act of perceiving and the object of perception. As Russell expressed himself, the argument “affords a fresh illustration of the necessity of distinguishing between sense-data and physical objects”. Direct realists, however, have traditionally rejected the time lag argument simply by replying that we can directly visually perceive into the past.

I show that such reply originates a serious threat to direct realism as well as to the disjunctive theory of perception – a philosophical position which is commonly taken as a vindication of direct realism. As a consequence of their conceding that we can directly visually perceive into the past, direct realists seem forced to accept the untenable claim that there are some events counting as both perceptions and hallucinations.