  Łukasiewicz worked on problems of the methodology of the empirical sciences in 1902–1910. At first, he tried to develop the inverse theory of induction (induction as inversed deduction) proposed by Jevons and Sigwart. However, he abandoned this project very soon and adopted a radical deductionist standpoint. For him, induction plays no significant role in science. Deduction remains the only credible mode of reasoning in all spheres of science. As applied in empirical science, it leads to negative results; that is, it can show that some hypotheses are false in the face of empirical data. Łukasiewicz also offered a formal argument against induction derived from probability theory. Assume that H is a universal hypothesis. Its a priori probability is equal (or close) to zero and no further empirical data can increase it. These ideas contain the main points of Popper’s philosophy of empirical science.