Formal semantics 909888 210172893 2008-05-04T20:31:58Z Hans Adler 5773149 add link to semantics :''See also '''[[Formal semantics of programming languages]]'''.'' '''Formal semantics''' is the study of the [[semantics]], or [[interpretation]]s, of [[formal language]]s. A formal language can be defined apart from any interpretation of it. This is done by designating a [[set]] of [[symbol]]s (also called an [[alphabet]]) and a set of [[formation rules]] (also called a ''formal grammar'') which determine which [[String (computer science)|string]]s of symbols are [[well-formed formula]]s. When [[transformation rules]] (also called ''rules of inference'') are added, and certain sentences are accepted as [[axiom]]s (together called a [[deductive system]] or a ''deductive apparatus'') a [[logical system]] is formed. An interpretation is an assignment of [[meaning]]s to these symbols and [[truth-value]]s to its sentences. <ref>The Cambridge Dictionary of Philosophy, ''Formal semantics''</ref> The truth conditions of various sentences we may encounter in [[argument]]s will depend upon their meaning, and so conscientious logicians cannot completely avoid the need to provide some treatment of the meaning of these sentences. The '''semantics of logic''' refers to the approaches that logicians have introduced to understand and determine that part of meaning in which they are interested; the logician traditionally is not interested in the sentence as uttered but in the [[proposition]], an idealised sentence suitable for logical manipulation. Until the advent of modern logic, [[Aristotle]]'s ''[[Organon]]'', especially ''[[De Interpretatione]]'', provided the basis for understanding the significance of logic. The introduction of [[quantification]], needed to solve the [[problem of multiple generality]], rendered impossible the kind of subject-predicate analysis that governed Aristotle's account, although there is a renewed interest in [[term logic]], attempting to find calculi in the spirit of Aristotle's syllogistic but with the generality of modern logics based on the quantifier. The main modern approaches to semantics for formal languages are the following: * '''[[Model-theoretic semantics]]''' is the archetype of [[Alfred Tarski]]'s [[semantic theory of truth]], based on his [[T-schema]], and is one of the founding concepts of [[model theory]]. This is the most widespread approach, and is based on the idea that the meaning of the various parts of the propositions are given by the possible ways we can give a recursively specified group of interpretation functions from them to some predefined mathematical domains: an [[interpretation (logic)|interpretation]] of [[first-order predicate logic]] is given by a mapping from terms to a universe of [[individual]]s, and a mapping from propositions to the truth values "true" and "false". Model-theoretic semantics provides the foundations for an approach to the theory of meaning known as [[Truth-conditional semantics]], which was pioneered by [[Donald Davidson (philosopher)|Donald Davidson]]. [[Kripke semantics]] introduces innovations, but is broadly in the Tarskian mold. * '''[[Proof-theoretic semantics]]''' associates the meaning of propositions with the roles that they can play in inferences. [[Gerhard Gentzen]], [[Dag Prawitz]] and [[Michael Dummett]] are generally seen as the founders of this approach; it is heavily influenced by [[Ludwig Wittgenstein]]'s later philosophy, especially his aphorism "meaning is use". * '''[[Truth-value semantics]]''' (also commonly referred to as ''substitutional quantification'') was advocated by [[Ruth Barcan Marcus]] for modal logics in the early 1960s and later championed by Dunn, Belnap, and Leblanc for standard first-order logic. James Garson has given some results in the areas of adequacy for intensional logics outfitted with such a semantics. The truth conditions for quantified formulas are given purely in terms of truth with no appeal to domains whatsoever (and hence its name ''truth-value semantics''). * '''[[Game semantics|Game-theoretical semantics]]''' has made a resurgence lately mainly due to [[Jaakko Hintikka]] for logics of (finite) partially ordered quantification which were originally investigated by [[Leon Henkin]], who studied ''Henkin quantifiers''. * '''[[Probabilistic semantics]]''' originated from H. Field and has been shown equivalent to and a natural generalization of truth-value semantics. Like truth-value semantics, it is also non-referential in nature. == References == {{reflist}} {{portalpar|Logic}} {{Logic}} [[Category:Logic]] [[Category:Semantics]] [[Category:Formal languages]] {{logic-stub}} [[hu:Logikai szemantika]] [[ja:形式意味論]] [[zh:逻辑的语义]]