Abstract
Abstract: In anticipation of Russell’s new introduction to his 1925 second edition of Principia Mathematica , Jean Nicod wrote a letter which is reproduced in Russell’s Autobiography . In the letter, Nicod wrote: “Since you are re-publishing Principia , I may remind you that I have proved both Permutation and Association by help of the other three primitive props (Tautology, Addition, and the syllogistic prop.), where I only changed the order of some letters. It is in the Memoir I wrote for the b.a. degree. I have entirely forgotten how it is done.” In this paper, I surmise what Nicod had in mind.