Robin Catalogue:
A. MS., n.p., August 17-19, 1910, pp. 1-7, 2-3.
Note: This manuscript was meant to serve as a “Preface,” with MS. 632 serving as the “Introduction.” Comments on Arnauld’s L’art de penser and on the Port Royal Logic. All reasoning consists in interpreting signs; all thought is in signs. System of existential graphs: the simplest system capable of expressing exactly every possible assertion. Definition of “sign.”