Jan Lukasiewicz Jan Lukasiewicz:
Jan Lukasiewicz is known all over the world as the founder of the first non-classical logical calculus, the so-called trivalent or polivalent logic, and as one of the most prominent and significative logicians of this century. But he was also very active in historical research on logic, giving a new and up-to-date interpretation of Aristotle's syllogism and of the Stoics' propositional calculus. His activity is strictly connected to the school founded by Kazimierz Twardowski, whose first pupil he was in Lvov . Maybe less known, but very significant, was his philosophical reflection about science and the role that creativity plays in the invention of theories, regarding which he followed an anti-inductive attitude in many aspects similar to Popper's conceptions  ¶ 5:02 AM