Peirce's Theories of Assertion

Until well into the 1890s, Peirce did not pay special attention to the act of asserting a proposition, and he used “proposition” and “assertion” interchangeably. This began to change in the period of the “Grand Logic” and the “Short Logic”, and in Peirce’s vast semiotic development after 1902, no less than three theories of assertion are developed to account for the ability of certain signs to claim truth. One is assertion as a special self-reference of proposition signs, claiming that the sign itself is indexically connected to its object as a truth grant; another is the assumption of social responsibility for the sign’s truth on the part of the utterer; the third is the purpose of asserting a proposition, namely to persuade some interlocutor about the truth of the sign. These three theories are oftentimes developed in isolation, but this paper argues they fit together in the way that the third pre-supposes the second, in turn presupposing the first.