With material on his early philosophical views, his contributions to set theory and his work on nominalism and higher-order quantification, this book offers a uniquely expansive critical commentary on one of analytical philosophy’s great ...

The paradox of material implication has remained unresolved since antiquity because it was believed that the nature of implication was entailment. The article shows that this nature is opposition and therefore the name "implication" should be replaced with the name "competition". A solution to the paradox is provided along with appropriate changes in nomenclature, the addition of connectives and the postulate that the biconditional take over the role of the previous implication. In addition, changes to the nomenclature of logic gates (...) reflecting the competition in electronics are proposed. (shrink)

Paradoks implikacji materialnej pozostawał nierozwiązany od starożytności, ponieważ uważano, że naturą implikacji jest wynikanie. Artykuł ukazuje, że tą naturą jest przeciwstawność. Zostaje podane rozwiązanie paradoksu wraz z odpowiednimi zmianami nazewnictwa, dodaniem konektywów i postulatem przejęcia roli dotychczasowej implikacji przez równoważność. Ponadto zaproponowane zostają zmiany nazewnictwa bramek logicznych, odwzorowujących kompetycję w elektronice.

In this paper I discuss Ernst Zermelo’s ideas concerning the possibility of developing a system of infinitary logic that, in his opinion, should be suitable for mathematical inferences. The presentation of Zermelo’s ideas is accompanied with some remarks concerning the development of infinitary logic. I also stress the fact that the second axiomatization of set theory provided by Zermelo in 1930 involved the use of extremal axioms of a very specific sort.1.

In this paper I first present in a few sentences the main theses of Ajdukiewicz’s theory of questions, then I briefly express the main theses of Professor Jonkisz’s book and the indisputable advantages of this work. Then I put forward my objections to some theoretical solutions adopted by the Author, namely the assumption that datum questionis is sequence of components without any syntactic requirements, the assumption about the special character of the so called generalized negation and the assumption that no (...) ontological assumptions are adopted in the work. The adoption of the language of set theory is already a privileging of a set theory ontology. (shrink)

The book provides a historical and systematic exposition of the semantic theory of truth formulated by Alfred Tarski in the 1930s. This theory became famous very soon and inspired logicians and philosophers. It has two different, but interconnected aspects: formal-logical and philosophical. The book deals with both, but it is intended mostly as a philosophical monograph. It explains Tarski’s motivation and presents discussions about his ideas as well as points out various applications of the semantic theory of truth to philosophical (...) problems. (shrink)

A theory of definitions which places the eliminability and conservativeness requirements on definitions is usually called the standard theory. We examine a persistent myth which credits this theory to Leśniewski, a Polish logician. After a brief survey of its origins, we show that the myth is highly dubious. First, no place in Leśniewski's published or unpublished work is known where the standard conditions are discussed. Second, Leśniewski's own logical theories allow for creative definitions. Third, Leśniewski's celebrated ‘rules of definition’ lay (...) merely syntactical restrictions on the form of definitions: they do not provide definitions with such meta-theoretical requirements as eliminability or conservativeness. On the positive side, we point out that among the Polish logicians, in the 1920s and 1930s, a study of these meta-theoretical conditions is more readily found in the works of Łukasiewicz and Ajdukiewicz. (shrink)

As is well known, Heinrich Scholz and his academic society maintained good scientific contacts with Polish logicians before, during, and after the Second World War. My interest here is to examine the details of their collaboration by presenting Scholz’s unpublished correspondence with Fr. Józef M. Bocheński. The following topics are discussed here: Polish logicians who survived the war and their current place of work; reorganization of the scholarly environment, didactic activities, duties, scholarly trips; current research topics, prospects for post-war publications, (...) and future publishing plans; information about Jan Łukasiewicz, Bolesław Sobociński, and Joachim Metallmann; personal matters. (shrink)