The Law of Contradiction in Modern Logic

Considering the important place assigned by philosophers and logicians to the law of contradiction, the remark will naturally be resented by many of the older schools of philosophy, and especially by Kantians, that “in spite of its fame we have found few occasions for its use.” ¹ Also in modern times, Benedetto Croce, an opponent of both traditional logic and mathematical logic, began the preface of the book of 1908 on Logic ² by saying that that volume “is and is not” a certain memoir of his which had been published in 1905.