This paper is a continuation of Part I under the same title. Its Chapter III contains results given in the following publications: U. Wybraniec-Skardowska, Teoria zdań odrzuconych (Theory of Rejected Sentences), (doctoral dissertation under the supervision of Jerzy Słupecki, published as a monograph), Zeszyty Naukowe Wyższej Szkoły Pedagogicznej w Opolu, Studia i Monografie, Nr 22 (1969), 5-131. G. Bryll, Związki logiczne pomiędzy zdaniami nauk empirycznych (Logical relations between sentences of empirical sciences). Zeszyty Naukowe Wyższej Szkoły Pedagogicznej w Opolu, Studia i (...) Monografie, Nr 22 (1969), 155-216. This chapter contains an attempt to formalize some questions of methodology of empirical sciences. The theory T is enriched here not only by new definitions but also by a new primitive term and new axioms. The most important notion defined in this chapter is the set IndX of all inductive conclusions obtained on the basis of sentences of the set X. The function CnI defined by the equality: CnI X = X u IndX, satisfies the axioms of the general theory of deductive systems. The set CnI X can be understood as a system of empirical sciences in a narrower sense. This paper is a development of the considerations of G. Bryll, included in the above-listed article by this author. (shrink)

This volume tackles the slippery subject of 'meaning'.

ZusammenfassungUnter den nichtlogischen Konstanten der Wissenschaftssprache werden zwei Arten unterschieden, die Beobachtungsterme und die theoretischen Terme . Die letzteren werden nicht durch Definitionen eingeführt, sondern durch Postulate zweier Arten, nämlich theoretische Postulate, zum Beispiel Grundgesetze der Physik, und Korrespondenzpostulate, die die theoretischen Terme mit Beobachtungstermen verbinden. Wie schon Hilbert gezeigt hat, können in dieser Weise sowohl die Mathematik als auch die theoretische Physik als ungedeutete Kalküle aufgestellt werden. Es wird hier kurz erklärt, dass durch diesen Aufbau auch den mathematischen Termen (...) eine Bedeutung beigelegt wird. Die theoretischen Terme erhalten durch die Korrespondenzpostulate wenigstens eine unvollständige Deutung. Es wird gezeigt, wie die Unterscheidung von analytischen und synthetischen Sätzen auch für die theoretische Sprache definiert werden kann.Among the non‐logical constants of the language of science two kinds are distinguished, the observation terms and the theoretical terms . The latter terms are introduced, not by definitions, but by postulates of two kinds, theoretical postulates, e.g., basic laws of physics, and correspondence postulates which connect the theoretical terms with observation terms. As Hilbert has explained, both mathematics and theoretical physics can in this way be constructed in the form of uninterpreted calculi. It is here briefly indicated that by this method of construction also the mathematical terms have meanings assigned to them. The theoretical terms obtain at least an incomplete interpretation by means of the correspondence postulates. It is shown how the distinction between analytic and synthetic sentences can be defined also for the theoretical language. (shrink)

This paper was written with two aims in mind. A large part of it is just an exposition of Tarski’s theory of truth. Philosophers do not agree on how Tarski’s theory is related to their investigations. Some of them doubt whether that theory has any relevance to philosophical issues and in particular whether it can be applied in dealing with the problems of philosophy (theory) of science. In this paper I argue that Tarski’s chief concern was the following question. Suppose (...) a language L belongs to the class of languages for which, in full accordance with some formal conditions set in advance, we are able to define the class of all the semantic interpretations the language may acquire. Every interpretation of L can be viewed as a certain structure to which the expressions of the language may refer. Suppose that a specific interpretation of the language L was singled out as the intended one. Suppose, moreover, that the intended interpretation can be characterized in a metalanguage L +. If the above assumptions are satisfied, can the notion of truth for L be defined in the metalanguage L + and, if it can, how can this be done? Many students of Tarski’s conception will find the above exposition inconsistent with their own views on the essence of Tarski’s conception. On the other hand, as it is argued in this paper, the proposed interpretation of Tarski’s ideas allows one to use Tarski’s theory as a fundamental tool for semantic analyses of various theories, factual theories in particular. More specifically, it is argued that Tarski’s theory of truth allows one to clearly oppose a theory meant to be certain deductive system (a set of accepted sentences, say axioms, and a logical machinery for deducing from them new ones) and a theory meant to be a certain semantic system, i.e a set of sentences that serve to communicate some states of affairs and to use that opposition to explicate and occasionally also define the notion of truth. The opposition in question is of the utmost significance for analyzing some developments in both mathematics and factual sciences. The approach which is concerned with the logical relations between the elements of science such an approach is throughout this paper called analytical is put into question. The growth of science is determined by how well scientific theories are able to account for factual states of affairs. The intuitive notion of truth applied by the scientists does not necessarily correspond in a straightforward way to its Tarskian counterpart. On the other hand, as is claimed in this paper, the Tarskian notion of truth offers as adequate explication of intuitive notion of truth as possible. (shrink)

The general aim of this book is to provide an elementary exposition of some basic concepts in terms of which both classical and non-dassicallogirs may be studied and appraised. Although quantificational logic is dealt with briefly in the last chapter, the discussion is chiefly concemed with propo gjtional cakuli. Still, the subject, as it stands today, cannot br covered in one book of reasonable length. Rather than to try to include in the volume as much as possible, I have put (...) emphasis on some selected topics. Even these could not be roverrd completely, but for each topic I have attempted to present a detailed and precise t’Xposition of several basic results including some which are non-trivial. The roots of some of the central ideas in the volume go back to J. Luka siewicz’s seminar on mathematicallogi. (shrink)

This paper was written with two aims in mind. A large part of it is just an exposition of Tarski’s theory of truth. Philosophers do not agree on how Tarski’s theory is related to their investigations. Some of them doubt whether that theory has any relevance to philosophical issues and in particular whether it can be applied in dealing with the problems of philosophy (theory) of science. In this paper I argue that Tarski’s chief concern was the following question. Suppose (...) a language L belongs to the class of languages for which, in full accordance with some formal conditions set in advance, we are able to define the class of all the semantic interpretations the language may acquire. Every interpretation of L can be viewed as a certain structure to which the expressions of the language may refer. Suppose that a specific interpretation of the language L was singled out as the intended one. Suppose, moreover, that the intended interpretation can be characterized in a metalanguage L +. If the above assumptions are satisfied, can the notion of truth for L be defined in the metalanguage L + and, if it can, how can this be done? Many students of Tarski’s conception will find the above exposition inconsistent with their own views on the essence of Tarski’s conception. On the other hand, as it is argued in this paper, the proposed interpretation of Tarski’s ideas allows one to use Tarski’s theory as a fundamental tool for semantic analyses of various theories, factual theories in particular. More specifically, it is argued that Tarski’s theory of truth allows one to clearly oppose a theory meant to be certain deductive system (a set of accepted sentences, say axioms, and a logical machinery for deducing from them new ones) and a theory meant to be a certain semantic system, i.e a set of sentences that serve to communicate some states of affairs and to use that opposition to explicate and occasionally also define the notion of truth. The opposition in question is of the utmost significance for analyzing some developments in both mathematics and factual sciences. The approach which is concerned with the logical relations between the elements of science such an approach is throughout this paper called analytical is put into question. The growth of science is determined by how well scientific theories are able to account for factual states of affairs. The intuitive notion of truth applied by the scientists does not necessarily correspond in a straightforward way to its Tarskian counterpart. On the other hand, as is claimed in this paper, the Tarskian notion of truth offers as adequate explication of intuitive notion of truth as possible. (shrink)

The idea of rejection of some sentences on the basis of others comes from Aristotle, as Jan Łukasiewicz states in his studies on Aristotle's syllogistic [1939, 1951], concerning rejection of the false syllogistic form and those on certain calculus of propositions. Short historical remarks on the origin and development of the notion of a rejected sentence, introduced into logic by Jan Łukasiewicz, are contained in the Introduction of this paper. This paper is to a considerable extent a summary of papers (...) which are not easily available, even to the Polish reader: (1) J. Słupecki, Funkcja Łukasiewicza (Łukasiewicz’s function), Zeszyty Naukowe Uniwersytetu Wrocławskiego, Seria B, nr 3 (1959), 33-40; (2) U. Wybraniec-Skardowska, Teoria zdań odrzuconych (Theory of Rejected Sentences), (doctoral dissertation under the supervision of Jerzy Słupecki, published as a monograph), Zeszyty Naukowe Wyższej Szkoły Pedagogicznej w Opolu, Studia i Monografie, Nr 22 (1969), 5-131; (3) G. Bryll, Kilka uzupełnień teorii zdań odrzuconych (Some supplements to the theory of rejcted sentences), Zeszyty Naukowe Wyższej Szkoły Pedagogicznej w Opolu, Studia i Mnografie, Nr 22 (1969), 153-154. The paper also contains a good number of results which have not been published yet. Chapter I contains results presented in the papers (1)-(3). It provides an extension of Alfred Tarski’s theory of deductive systems presented by him in the papers [1930]: Fundamentale Begriffe der Methodologie der deduktiven Wssenschaften, I and Über einige fundamentale Begriffe der Metamathematik. The enriched theory is marked with T. The most essential new concept in T is the function Cn-1, whose definition was given by Słupecki in (1) on the basis of the so-called Tarski’s general theory of deductive systems. It has the form: y e Cn-1X iff Ex e X (x e Cn {y}), where Cn is Tarski’s consequence operation. In accordance with the definition: A sentence y is rejected on the basis of the sentences of the set X iff at least one of sentences of X is a consequence of y (is deducible from y). The intuitive meaning of the rejection function Cn-1: on the basis of false sentences we can reject false sentences only (while by means of the consequence operation Cn on the basis of true sentences we can deduce true sentences only). The function Cn-1 is a generalization of the notion of rejected sentences which was introduced into logic by Łukasiewicz. The essential property of the rejection function Cn-1 is that it satisfies the axioms of general Tarski’s consequence Cn, so it is a consequence operation, called the rejection consequence. In addition, it is an additive and normal operation. In Chapter I, there are given notions analogous to those of the theory of deductive systems, but they are written down by means of the symbol ‘Cn-1’ and not ‘Cn’. There are established the properties of introduced notions and differences and analogies taking place between them and properties of respective notions of the theory T. There are also given generalizations of the notions of ‘decidable system’ and ‘consistent system’ used by Łukasiewicz. The short Chapter II contains axioms of the system T’ which is equivalent to the system T. The only difference between sets of primitive notions of these systems consists in the appearance of the function Cn-1 in the system T’ instead of the function Cn. This chapter reproduces the results given in (2), but they are partially simplified. (shrink)