Łukasiewicz and Leśniewski on Contradiction

It was in 1911 that Łukasiewicz and Leśniewski met. Leśniewski himself reported that at that time he had read Łukasiewicz’s masterpiece On the Principle of Contradiction in Aristotle (1910), and, as Lejewski knew from Łukasiewicz, he said he had come to criticize the author. In the same year Leśniewski wrote “An Attempt at a Proof of the Principle of Contradiction”, which was published in 1912 on Przegląd Filozoficzny and was addressed on the whole against Łukasiewicz’s book. Whereas the role played by the principle of contradiction in the development of Łukasiewicz’s ideas is generally speaking correctly underlined, it is not so in Leśniewski’s case. Surely the oblivion which covered Leśniewski’s early writings prevented the scholars from regarding the issue worthy of inquiry in his philosophy. Yet the controversy between Leśniewski and Łukasiewicz on the principle of contradiction may be considered quite rightly a touchstone between their very distant philosophical attitudes, which remained that way also later. It is hard to exaggerate the great weight Łukasiewicz’s monograph had in the Polish logico-philosophical scene. Although polemically inspired, Leśniewski did acknowledge the importance of Łukasiewicz’s work: