St. Leśniewski’s Protothetics

Abstract

In this paper I am discussing one of the three logical systems formulated by the late Professor Stanisław Leśniewski, Ph.D., namely, that which he at first named logistics and later protothetics ¹; on the two other systems, i.e. ontology and mereology I am working at present. As Professor Leśniewski’s manuscripts were destroyed during the Warsaw Uprising in 1944, the main source for this paper constitute the notes taken by students on his lectures, in the first place by the late Mr. Jerzy Billich of the Warsaw University. ‡ The initiative of collecting those notes which escaped destruction and of arranging systematically the result of Professor Leśniewski’ research work, was taken by Professor Tadeusz Kotarbiński, who asked me as one of Professor Leśniewski’s students to work on these notes. Professor Leśniewski left a great part of the results of his research work unpublished. Those which he did publish are often fragmentary and thus do not represent a complete picture of the systems he created. Besides, some of his papers are styled in an extremely difficult manner, while some others are at present almost unavailable. These are the reasons that Professor Leśniewski’s works are not much known, even in this country, and therefore subject to falling into oblivion, notwithstanding the fact that according to unanimous opinion of those who know them, they are of lasting value.

Bibliographical Note. This paper originally appeared in Studia Logica I (1953), 44–112, by permission of the Institute of Philosophy and Sociology of the Polish Academy of Sciences.