To determine whether argument is logical, this paper reviews the empirical literature on perception, memory, and reasoning. It finds cognitive processes to be inferential, thus supporting the assumption that argument is logical. It notes, however, that a cognitive view of argument must be taken to appreciate this logicality, because people commonly use premises not available in a rhetorical or experimental text to solve problems. The paper concludes that when these emendations are not noticed, many responses are taken for logical errors. (Author/FL)