Abstract
Our objectives in this paper are, first, to identify several puzzling aspects of the “Trilemma Argument” of Section 6 against the Sense Datum Theory; second, to resolve these puzzles by reconstructing the Trilemma Argument; third to point to a distinction Sellars makes between two versions of the Sense Datum Theory, the “nominalist” version and the “realist” version; fourth, to reconstruct Sellars’s arguments against both; and, finally, to find in an earlier paper, “Is There a Synthetic A Priori?” that his argument against the second version, assumed but not actually given in EPM, is against property realism and depends on taking language expressing propositional perception as fundamental and language expressing non-propositional perception as incomplete and derivative from the former.