W latach 1931-1934 Kazimierz Ajdukiewicz sformułował dwie wersje teorii znaczenia. Tarski wykazał, że druga wersja teorii dopuszcza moż- liwość istnienia równoznacznych nazw o różnej denotacji. Cecha ta zo- stała uznana przez Tarskiego i Ajdukiewicza za dyskwalifikującą teorię. W artykule dokonuję porównania obu wersji teorii, przede wszystkim ze względu na podstawową definicję wzajemnej wymienialności wyrażeń. Pokazuję, że wbrew rozpowszechnionej opinii zarzut Tarskiego dotyczy także pierwszej wersji teorii. Siła argumentu Tarskiego opiera się na założeniu, że żadna adekwatna teoria znaczenia nie może dopuszczać istnienia równoznacznych nazw o różnej denotacji. Podejmuję dyskusję z tym stanowiskiem.
EN
In the years 1931-1934 Kazimierz Ajdukiewicz formulated two versions of the theory of meaning. Tarski showed that the second version of the theory allows for the existence of synonymous names with different denotations. Tarski and Ajdukiewicz believed that this feature disqualified the theory. In the article I briefly present the assumptions of the theory and make a detailed comparison of both versions of the theory, primarily because of the basic definition of the interchangeability of expressions. For this purpose I present a formalization of the basic definitions and show that Tarski's objection also applies to the first version of the theory. The strength of Tarski's argument is based on the assumption that no adequate theory of meaning can permit the existence of synonymous names with different denotations. I undertake a discussion with this standpoint.
Jan Wawrzyniak maintains (in “Analiza i Egzystencja” 2011, Vol. 15) that Tarski’s solution of the liar antynomy is allegedand inconsistent. The author argues that such opinion is based on false assumptions and in order to demonstrate that Tarski’sreasoning is correct presents its detailed reconstruction.
We extend the work presented in [7, 8] to a regions-based, two-dimensional, Euclidean theory. The goal is to recover the classical continuum on a point-free basis. We first derive the Archimedean property for a class of readily postulated orientations of certain special regions, “generalized quadrilaterals” (intended as parallelograms), by which we cover the entire space. Then we generalize this to arbitrary orientations, and then establishing an isomorphism between the space and the usual point-based R × R. As in the one-dimensional case, this is done on the basis of axioms which contain no explicit “extremal clause” (to the effect that “these are the only ways of generating regions”), and we have no axiom of induction other than ordinary numerical (mathematical) induction. Finally, having explicitly defined ‘point’ and ‘line’, we will derive the characteristic Parallel’s Postulate (Playfair axiom) from regions-based axioms, and point the way toward deriving key Euclidean metrical properties.
The main question of our article is: What is the logical form of statements containing expressions such as “… is true” and “it is true that …”? We claim that these expressions are generally not used in order to assign a certain property to sentences. We indicate that a predicative interpretation of these expressions was rejected by Frege and adherents to the prosentential conception of truth. We treat these expressions as operators. The main advantage of our operational reading is the fact that it adequately represents how the words, “true” and “truth,” function in everyday speech. Our approach confirms the intuition that so-called T-equivalences are not contingent truths, and explains why they seem to be—in some sense—necessary sentences. Moreover, our operational readingof truth expressions dissolves problems arising from the belief that there is some specific property—truth. The fact that we reject that truth is a certain property does not mean that we deny that the concept of truth plays a very important role in our language, and hence in our life. We indicate that the concept of truth is inseparable from the concept of sentence and vice versa—it is impossible to explicate one of these concepts without appeal to the other.
In 1931-1934 Kazimierz Ajdukiewicz formulated two versions of the theory of meaning (A1 and A2). Tarski showed that A2 allows syn- onymous names to exist with different denotations. Tarski and Ajdukiewicz found that this feature disparages the theory. The force of Tarski’s argument rests on the assumption that none of adequate theories of meaning allow synonymous names to exist with different denotations. In the first part of this paper we present an appropriate fragment of A2 and Tarski’s argument. In the second part we consider an elementary interpreted language in which individual constants occur, but not functional symbols. For such a language we define semantically a relation of synonymity for simple names and show that it fulfills syntactical conditions formulated by Ajdukiewicz in A2 and allows synonymous names to exist with different denotations.
The aim of the article is to determine what role the liar sentence plays in our language. On the one hand, it seems to be well formed formula, and on the other, it does not seem to have any clear sense. At the beginning of the article I point what form an adequate solution of the liar paradox should take. In my opinion it could not consist in giving rules which do not allow to build such a sentence. The paradox remains unsolved until there is such a language in which it could be expressed. In the first part of the text I try to explain why Tarski’s solution is not satisfactory. If the semantical definition of truth is correct, the liar sentence could not lead to a contradiction because formulas which are not well formed could not be premises of any inference. From that follows that the so called liar paradox does not arise and that leads to the conclusion: ‘the reconstruction’ of the liar propounded by Tarski could not be correct. In the second part I present an approach to the liar which appeals to Frege’s and Wittgenstein’s conceptions of language. The conclusion of my consideration is that the liar sentence is nonsense, which means it is not given any sense – either its logical form is determined but we do not fix any definite meaning to some parts of it, or an attempt to determine its logical form in the standard way leads to regress ad infinitum.
Gödel’s first incompleteness theorem is sometimes said to refute mechanism about the mind. §1 contains a discussion of mechanism. We look into its origins, motivations and commitments, both in general and with regard to the human mind, and ask about the place of modern computers and modern cognitive science within the general mechanistic paradigm. In §2 we give a sharp formulation of a mechanistic thesis about the mind in terms of the mathematical notion of computability. We present the argument from Gödel’s theorem against mechanism in terms of this formulation and raise two objections, one of which is known but is here given a more precise formulation, and the other is new and based on the discussion in §1.
The subject of this article are three remarks which were not raised in previous publications concerning the semantic theory of knowledge of Kazimierz Ajdukiewicz. The first one pertains to the contradistinction of two basic questions which are hidden under the name “semantic theory of knowledge”. The second one pertains to the relation, and rather its lack, between Ajdukiewicz’s semantic theory of knowledge and Tarski’s semantic theory of truth. The third one pertains to the relation between Husserl’s intentional theory of language and Ajdukiewicz’s semantic theory of knowledge understood as a metaepistemological project.
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