anti-psychologism, J. Łukasiewicz, K. Twardowski, many-valued logic

Although Łukasiewicz was the first proponent of Husserl’s anti-psychologism in the Lvov-Warsaw School, his later concept of anti-psychologism has some features that are incompatible with Husserl's concept. Łukasiewicz supported Husserl’s views in a short paper “Teza Husserla o stosunku logiki do psychologii” that appeared in 1904 and later also in his famous paper “Logic and Psychology” which was published in 1910. At the same time, Łukasiewicz, however, started to question the fact that the laws of logic are settled, which was an essential part of anti-psychologism for Husserl. Łukasiewicz questioned the law of contradiction in his book On Aristotle’s Law of Contradiction and finished his denial of the unchangeability of laws of logic by an introduction of his systems of many-valued logic. His first system, the three-valued logic, is clearly based on the denial of the law of bivalence. In his later works, Łukasiewicz questioned also the distinction between axiomatic and empirical sciences and the truthfulness of apodictic statements, which was another important component of Husserl’s anti-psychologistic argumentation. Nonetheless, he still claimed that psychologism is undesirable in logic in his later works. Therefore, the aim of my talk is to provide the definition of Łukasiewicz’s anti-psychologism.