 De Morgan’s Formal Logic did not gain significant recognition, primarily because it was a large collection of small facts without a significant synthesis. Boole’s The Mathematical Analysis of Logic had powerful methods that caught the attention of a few scholars such as De Morgan and Arthur Cayley (1821–1895); but immediately there were serious questions about the workings of Boole’s algebra of logic: Just how closely was it tied to ordinary algebra? How could Boole justify the procedures of his algebra of logic? In retrospect it seems quite certain that Boole did not know why his system worked. His claim, following Gregory, that in order to justify using ordinary algebra it was enough to check the commutative law \(XY = YX\) for multiplication and the distributive law \(X(Y + Z) = XY + XZ\), is clearly false. Nonetheless it is also likely that he had checked his results in a sufficient number of cases to give substance to his belief that his system was correct.