Abstract

This volume offers to the English-speaking world a collection of important works by the eminent twentieth century logician, Jan Lukasiewicz, many of which are here translated into English for the first time. This edition differs significantly from the Polish edition which appeared in 1961—containing ten logic papers not appearing there and omitting articles primarily of interest to the Polish reader. In addition to writing in Polish, Lukasiewicz also published works in French, English, and notably in German, and sometimes translated his own works from one language to another. One of the most valuable works on the history of logic is Lukasiewicz’ paper, "On the History of the Logic of Propositions". Lukasiewicz points out the difference between the two basic areas of formal logic, the logic of propositions and the logic of terms, undifferentiated before the development of modern mathematical logic. The understanding of this distinction leads Lukasiewicz to trace the history of propositional logic back to its original development by the Stoics, its further development by the medieval Scholastics, and its axiomatization by Gottlob Frege. The status of mathematical logic is discussed in various works. The most basic system is propositional logic, upon which depend the other logical disciplines and also mathematics. Mathematical logic, also called logistic, is independent of philosophy and espouses no philosophical viewpoint. Early in his career, Lukasiewicz refers to mathematical logic as the logic of algebra and uses mathematical symbolism to represent logical propositions. Later he introduces what we now call "Polish notation," in particular, "Cpq" for "if p, then q" and "Np" for "it is not the case that p" for the primitive functions, eliminating the need for punctuation. He adopts the symbols Π and Σ for quantification from Charles S. Peirce, and also brings to light the almost unknown fact that it was Peirce who invented the matrix method in 1885. The paper, "Investigations into the Sentential Calculus", written by Lukasiewicz and Tarski embodies the results of a decade of research on the sentential calculus initiated by Lukasiewicz at the University of Warsaw systematically compiling the contributions of five logicians: Lindenbaum, Sobocinski, Wajsberg, Tarski, and Lukasiewicz. The approach is metalogical and depends heavily upon set theoretic concepts; it covers both the matrix and axiomatic methods. One of the problems that preoccupied Lukasiewicz was that of determinism, which led to his development of three-valued logic. A proposition such as "I shall be in Warsaw at noon on 21 December of next year" is neither true nor false; a third truth value is needed, one which Lukasiewicz calls "the possible." Another area to which Lukasiewicz contributed is modal logic, proving that modal logic cannot be two-valued. Lukasiewicz’ analysis and axiomatization of Aristotle’s syllogistic is not included in the present volume since an English edition by Lukasiewicz on this topic is available. We have here briefly touched upon a few of Lukasiewicz’ numerous achievements in logic; the best means of appreciating them is to read his works.—T. G. N.