Poinsot versus Peirce on Merging with Reality by Sharing a Quality

C. S. Peirce introduced the term “icon” for sign-vehicles that signify their objects in virtue of some shared quality. This qualitative kinship, however, threatens to collapse the relata of the sign into one and the same thing. Accordingly, the late medieval philosopher of signs John Poinsot held that, “no matter how perfect, a concept [...] always retains a distinction, therefore, between the thing signified and itself signifying.” Poinsot is touted by his present-day advocates as a realist, but I believe that, judged by realist standards, his requirement of minimal dissimilarity backfires. Poinsot thinks that, in analyzing the sign, we should stop before a full merger between sign-vehicle and object is reached. Peirce, by contrast, saw good reason to push the analysis all the way down to one isolated quality. Because such a qualitative merger can lend support to realism, I favour Peirce’s stance.