Page 316 - Encyclopedia of Philosophy of Language

Language and Logic
Kripke S 1979 A puzzle about belief. In: Margalit A (ed.) Meaning and Use. Reidel, Dordrecht
Levesque H J 1984 A logic of implicit and explicit belief. In: Proceedings AAA1-84. Austin, TX
Mates B 1950 Synonymity. In: Linsky (ed.) 1952 Semantics and the Philosophy of Language. The University of Illinois Press, Urbana, IL
Moore R C 1989 Prepositional attitudes and Russellian propositions. In: Bartsch R, van Benthem J F A K, van Emde Boas P (eds.) Semantics and Contextual Expression: Proceedings of the Sixth Amsterdam Colloquium. Foris, Dordrecht
Moore R C, Hendrix G C 1982 Computational models of belief and the semantics of belief sentences. In: Peters S, Saarinen E (eds.) Processes, Beliefs and Questions. Reidel, Dordrecht
Muskens R A 1991 Hyperfine-grained Meanings in Classical Logic. Logique et Analyse 133-134: 159-76
Muskens R A 1995 Meaning and Partiality. CSLI, Stanford, CA
Quine W V O 1966 Quantifiers and prepositional attitudes. In: The Ways of Paradox. Random House, New York Rantala V 1982 Impossible worlds semantics and logical
omniscience. In: Niiniluoto J, Saarinen E (eds.) Intensional
Logic Theory and Applications. Helsinki
Stalnaker R 1984 Inquiry. The MIT Press/Bradford Books,
Cambridge, MA
Thomason R H 1980 A model theory for prepositional atti-
tudes. LaPh 4: 47-70
Wansing H 1990 A general possible worlds framework for
reasoning about knowledge and belief. Studio Logica 49: 523-39
The study of reasoning has entered into a new phase since the 1970s. For two thousand years the 'science of reasoning' was, essentially, the Aristotelian tradition; then in the nineteenth and twentieth centuries it took a distinctly mathematical turn: but since the 1970s it has returned to studying 'real reasoning'—reasoning which people actually use in order to convince one another—and this is leading to new ideas about the nature, structure, and evaluation of reasoning, par- ticularly from the perspectives of informal logic, linguistics, and cognitive psychology.
1. Historical Background
Though the Stoics invented prepositional logic, Ari- stotle was undoubtedly the key figure in the 'science of reasoning* until the nineteenth century. Aristotle distinguished three different kinds or aspects of reasoning. These were: (a) 'analytic'—the science of demonstrative reasoning, the kind of reasoning which is characteristic of mathematics; (b) 'dialectic'—the science of argumentative dialogue; and (c) 'rhetoric'— the science of persuasion. Aristotle's analytic is the beginning of what is called 'logic' and is to be found mainly in his Prior Analytics and Posterior Analytics. His theory of argumentative debate is to be found in his Topics and De Sophisticis Elenchis, and his theory of good and convincing oratory is to be found in his Rhetoric. The theory of the syllogism is probably Aristotle's most famous contribution to the theory of reasoning and is still widely studied. A syllogism is an argument with two premises and a conclusion, where all three sentences are of one of the following forms,
(A) 'All As are Bs,' (E) 'No As are Bs,' (I) 'Some As are Bs,' (O) 'Some As are not Bs,' and the premises have one term in common, as in:
All crocodiles are amphibious creatures (A)
No amphibious creatures are lovable (E) Therefore
No crocodiles are lovable. (E)
where 'amphibious creature' is the term common to both premises. Prior (1962) contains an excellent account of Aristotle's theory of the syllogism.
In the medieval world Aristotle's theory of the syl- logism was studied; 'disputations' were conducted according to strict rules deriving from the theory of dialectic; and rhetoric also remained of central import- ance. However, with the rise of science, dialectic and rhetoric declined in importance and the study of reasoning became increasingly the study of analytic. Furthermore, the methods by which reasoning was studied became increasingly mathematical. Some of the most important figures in this development were Leibniz, Bolzano, Boole, and De Morgan, but by far the most important was Gottlob Frege (1848- 1925), and modern logic is universally recognized to date from the publication of his Begriffsschrift; (1879).
2. The Influence of Frege
Frege was a mathematician who was mainly interested in studying mathematical reasoning by mathematical methods. He generalized certain mathematical ideas, notably those of 'variable' and 'function,' to produce
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Reasoning A. Fisher