What Is a Sign? Peirce on Signs and Propositions

The paper argues that “sign” is most often used by Peirce in the sense of “proposition,” or more precisely, that only propositions adequately satisfy Peirce’s definition of the sign. The argument has the form of an exegetical syllogism in Barbara: complete signs are propositions (major premise), Peirce’s definition of the sign is actually a definition of complete signs (minor premise); therefore, the definition of the sign is actually a definition of propositions (conclusion). The author provides textual evidence in support of both the major and the minor premise of my exegetical syllogism, especially in Peirce’s mature production (1902–1912). He also evidences how this view helps making sense of several things that Peirce says about signs and their classification, including his claim that “logic has to be considered as semiotics.”