Abstract

PART I The first chapter contains some arguments in favour of four general requirements on a theory of meaning which Michael Dummett has formulated: connection between meaning and understanding, distinction between sense and force, compositionality, and manifestability. The second chapter contains a condensed account of the theory of meaning centered on bivalent truth-conditions, and a detailed analysis of Dummett's argument against such a theory and against classical logic. The third chapter is a description of Dummett's theory of meaning centered on the notion of direct verification, and of Prawitz's semantics which can be embedded in the latter theory of meaning so as to justify intuitionistic logic. The weakest points of Dummett's idea are two: 1) it is difficult to make verificationism compatible with the holistic character of justification; 2) logical revisionism may involve a too drastic disagreement between verificationism and linguistic practice. -/- PART II. The second part contains a presentation of a theory of meaning centered on the notion which I have called immediate argumental role. The fundamental idea of the theory is that the sense of a word is given by all the argumentation rules concerning the word. Chapters IV-VII make precise the basic idea by explaining the notion of "argumentation rule" and by defining the notion of "concerning", and other notions among which "immediate argumental role of a sentence" and "global argumental role". Chapters VIII-X deal with the main philosophical features of the theory: 1) the theory satisfies the four requirements considered in the first chapter; 2) despite its compositionality, the theory is compatible with epistemological holism; 3) the theory admits the possibility of meaningful paradoxical languages; 4) the theory distinguishes between the understandability of a language and its correctness in a given epistemic situation (understandability does not imply correctness); 5) the theory is pluralist with respect to the understandability of different logics and neutral with respect to their validity.