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."
Arnauld Antoine, Graphs existential, Logic (modal see Modality), Port Royal logic, Reasoning (probable see also Probability), Sign(s), definition of Sign(s), Thought
pp. 1-7, 2-3
(Essays 1st Pref.)