Speculative rhetoric, methodeutic, and Peirce’s hexadic sign-systems
Authors: Jappy Tony 
Published: November 2017

Abstract
By 1903 Peirce had defined logic broadly as a “Philosophy of Representation,” an over-arching, organically organized cenoscopic science formed of speculative grammar, critic, and speculative rhetoric. Corresponding respectively to the three trichotomies of the sign that he had established at this time, the three branches of the grand logic concerned definitions of the sign, inquiry into the relation between sign and object and, finally, inquiry into the relation between sign and interpretant. In this latter case he hesitated between the labels “speculative rhetoric” and “methodeutic.” Also noticeable at this time is a hesitation concerning the scope of such an inquiry: the “logical study of the theory of inquiry” as opposed to “the doctrine of the general conditions of the reference of Symbols and other Signs to the Interpretants which they aim to determine,” a conception of logic reminiscent of the traditional art of persuasion. This polarity seems to have been confirmed in the 1904 paper “Ideas, Stray or Stolen about Scientific Writing” with its reference to the efficient written communication of the scientist’s results. It shows Peirce not so much adapting his speculative rhetoric to the traditional notion as explaining how the “abstract” cenoscopic science might help to organize the empirical idioscopic rhetorical sciences by determining three modes of specialization each with its specific divisions. However, in a letter to Lady Welby in October of that same year he introduced an initial hexadic sign-system which, following the earlier triadic classification, was composed of three supplementary relational criteria involving the sign respectively with its immediate object, its immediate interpretant, and its dynamic interpretant, all based on the more complex hexadic conception of semiosis announced in a letter to lady Welby dated December 23, 1908. It is noteworthy that the way the sign is classified with respect to the three interpretants in the 1904 letter corresponds closely to aspects of the modes of specialization described in the earlier paper. In 1906 he expressed his preference for the term “methodeutic” and its essentially methodological scope: as late as 1911, for example, he continued to define the third branch of logic as showing “how to conduct an inquiry.” Moreover, both methodeutic and the former over-arching philosophy of representation seem to have figured less prominently in his later theoretical preoccupations. Peirce may have been too involved in developing his Graphs and the hexadic and, ultimately, decadic systems of semiotic classification to define fully a “method of methods.” He might, too, have rejected the label “rhetoric” as being too close to the traditional art of persuasion whose three modes of specialization he had described in 1904. Alternatively, it is possible that his evolving understanding of the three interpretants absorbed any lingering rhetorical complexion his theory of scientific methodology may have had, and rendered it redundant in this more complex and comprehensive conception of semiosis. It is this latter possibility that the paper seeks to examine.