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)

The role of classical logic as the base of formalized scientific theories seems to be unshakable. Yet legitimate doubts about its universal applicability in science have resulted in the development of alternative systems, among which constructive and modal logic are discussed in syntactic and semantic terms.

The paper brings a critical analysis of the assumptions on which K. Ajdukiewicz (1934) based his considerations concerning the theory of meaning and proposes to look at these problems from a new research perspective. The considerations sought to analyse the modes of accepting propositions which call for a contact with empirical reality, therefore to apply some empirical procedures (observations, tests, experiments).

11 original. Modifications which I introduced are radical and often far going. In my opinion the Polish text had two main drawbacks. It was overloaded with informal considerations and at the same time formal concepts included in some parts of the book were presented in a too complicated way. Of course one of the motives to revise it was also the fact that much time has passed since I finished writing the Polish version and obviously certain decisions and ideas contained (...) in the first edition seem not quite relevant now. So it is not only the desire to make the exposition clearer but also the reasons of substantial nature which motivated writing a revised version. I do not think it desirable to bother the reader with a detailed discussion of all changes to which the Polish version was subjected and that is why I will confine myself to pointing out only the most significant ones. Explanations concerning logical and set-theoretical notions applied in the book have been shortened as much as possible, in the Polish version one whole chapter was devoted to the discussion of them. (shrink)

In this note I am reflecting on interrelations between three concepts of truth: that employed by Hilbert arguing his formalist view on the nature of mathematics, Freges idea of truth supported by mathematical intuition, and known as Aristotelian correspondence idea of truth concerning any propositions not merely mathematical.

An axiomatic theory of non-monotonic consequence relations patterned upon some finitistic ideas going back to Gentzen was suggested by Gabbay [1985]. 1 More recently, an infinitistic approach patterned upon Tarski’s theory of consequence operation was examined by Makinson [l98.]. We compare the two approaches and examine them vis-`a-vis some intuitive adequacy conditions. An enlarged version of this note will appear in Studia Logica , in particular the reader is referred to it for the proofs of the results stated here.

This paper was presented at the Annual Conference of the Australian Association for Logic, Melbourne, November, 1979. The present note being complementary to [1], I shall only brie y recall the key notions to be exploited here, and for more details the reader is advised to consult [1]. By a propositional logic we mean a couple , where L is a propo- sitional language and C a structural consequence de- ned on L. A couple W = is said to be (...) a referential matrix for the language L i there exists a non-empty set T such that the following two conditions are satised: i. A is an abstract algebra similar to L, whose all elements belong to f0; 1g T , i.e. they are mappings from T into the two-element set f0; 1g. ii. D = ffa 2 A : a = 1g : t 2 Tg. (shrink)

The author presents three formal concepts of language: syntactical, semantical and pragmatical one. They are used to provide an analysis of the problem of context in the language.

I shall assume that the reader is familiar with the notions dened in [2] and [3]. A consequence C dened over a propositional language L will be said to be d-structural i the consequence dC dual with respect to C is structural. The following propositions holds true.

Ryszard Wójcicki's book „Ajdukiewicz. A Theory of Meaning” opens a series of publications Filozofia polska XX wieku [Polish Philosophy of XXth Century], created by Wójcicki. The main subject of the book is a theory of the meaning of linguistic expressions, which was formulated in the thirties and is known as a directival theory of meaning. The aim that the author has set for himself is not only to present and popularise that theory (these aims are implied by (...) the character of the series), but also the evaluation of its material adequacy and its significance for further investigations of language as a means of representation and transmission of knowledge. Adam Nowaczyk tries to show that Wójcicki's critique of Ajdukiewicz's conception is unjustified, for the fallacy allegedly committed in this conception is either only apparent or else easily remediable. Wójcicki disagrees with Nowaczyk's objection. (shrink)

The anthology presents a selection of methodological writings pub lished by Polish logicians after World War 11. All the papers belong to what may be called Logical Methodology or Logical Theory of Science. The epithet 'logical' characterizes rather the general point of view than the particular methods employed by the authors. Apart from articles which make an essential use of different formal methods, there are many which do not involve any formal apparatus whatsoever. The problems the papers deal with may (...) be characterized as problems of the general methodology of empirical science. The papers do not consider the methodological problems of formal knowledge, and, as a rule, they are concerned with empirical science as a whole and not with some of its specific branches. The topics covered by the selected writings include the main issues and controversies discussed within the contemporary methodology of science. A considerable part of the anthology is con cerned with the semantics of empirica1languages and considers problems such as interpretation of observational and theoretical terms, analyticity, empirical meaningfulness, etc. Another group of papers deals with the problem of induction and examines various ways of its justification. Some articles discuss the nature and the status of methodology itself. The materials have been selected so as to make up a whole representative of what has been done in this field in Poland since 1945. The book comprises 33 articles by 20 authors. (shrink)

The title of this paper is a theorem, which I am going to state and prove. The theorem extends from prepositional to predicate languages the result I presented in [5].

The two main points of this contribution are the following: (1) Applied mathematical theories might complement physical theories in an essential way; some applied mathematical theories allow us to understand phenomena we are unable to explain by resorting to physical theories alone, (2) In the case of social sciences it might be necessary to account for examined phenomena by resorting to the idea of goal-oriented activity (the causal approach typical for natural science might be unsatisfactory). Weinberg's idea of grand reductionism (...) ignores the two above mentioned facts and hence overestimates the foundational role of physics and its methodology. (shrink)