Routledge Dictionary of Language and Linguistics.pdf

Dictionary of language and linguistics 326personal pronounReferencesdisjunction [Lat. disiunctio ‘separation’]1 In formal logic the conjunction of two elementary propositions p and q by the logicalparticle or 1 which is true if and only if at least one of the elementary propositions is true.Or 1 corresponds to Lat. vel (‘or also’) which can be paraphrased by ‘one or the other, orboth.’ This inclusive (i.e. non-exclusive) or, which is basic to disjunction, must bedifferentiated from the exclusive or 2 (Lat. aut…aut…) which means ‘either one or theother, but not both’), compare or 1 (Louise is either sad or tired, (or perhaps both)) withor 2 (Louise is either older or younger than her friend, (but in no case both)). In everydayusage the exclusive or 2 is more common (expressed by either/or or otherwise), since theinclusive reading is usually barred by the pragmatic context. This relation is representedas follows in the (two-place) truth table:p q p q 1 p q 2t t t ft f t tf t t tf f f fThe term ‘disjunction’ refers to the operation of the two-place sentence operator or aswell as to the propositional connective defined by it. The propositions connected by orare not necessarily semantically cohesive. For that reason the connection Socrates is aphilosopher or Aristotle is a unicorn is ‘true’ (because the first part of the sentence istrue), while it would have to be rejected as an utterance in an actual speech situation as anunsuccessful speech act ( speech act theory). With the aid of set theory, disjunctioncan be semantically characterized as the union of both model sets that make thepropositions connected with each other true.ReferencesPelletier, J.F. 1977. Or. TL 4. 61–74.formal logic2 In unification grammar the dual of the operation of unification, used, for example,in Functional Unification Grammar (FUG), lexical Unification Gramma (LUG), r andHeaddriven Phrase Structure Grammar (HPSG). The disjunction of two featurestructures indicates the unification bundle of the denotata of their two disjuncts. The