Linguistic entailment

{{Short description|Concept in linguistics}}

{{other uses|Entail (disambiguation)}}

Linguistic entailments are entailments which arise in natural language. If a sentence A entails a sentence B, sentence A cannot be true without B being true as well.{{Cite book|title=Semantic Entailment and Formal Derivability|last=Beth|first=Evert Willem|year=1955}} For instance, the English sentence "Pat is a fluffy cat" entails the sentence "Pat is a cat" since one cannot be a fluffy cat without being a cat. On the other hand, this sentence does not entail "Pat chases mice" since it is possible (if unlikely) for a cat to not chase mice.

Entailments arise from the semantics of linguistic expressions.{{Cite book|title=Lexical Meaning|last=Murphy|first=M. Lynne|publisher=Cambridge Textbooks in Semantics|year=2010|location=Cambridge|pages=31–40}} Entailment contrasts with the pragmatic notion of implicature. While implicatures are fallible inferences, entailments are enforced by lexical meanings plus the laws of logic.{{Cite book|title=Presupposition and Implicature in Compositional Semantics|last=Sauerland|first=U|publisher=Pelgrave|year=2007}} Entailments also differ from presuppositions, whose truth is taken for granted. The classic example of a presupposition is the existence presupposition which arises from definite descriptions. For example, the sentence "The king of France is bald" presupposes that there is a king of France. Unlike an entailment, presuppositions survive when the sentence is negated. The negation test can be used to determine the difference between entailment and presupposition.{{Cite journal |last=Indarti |first=Gatri Asti Putri |date=2015-04-01 |title=Distinguishing Entailment and Presupposition Under Negation Test |url=http://pdfs.semanticscholar.org/c42d/20aa9d0ca853ca449a13b7a0fe3b34d05893.pdf |journal=Language and Language Teaching Journal |volume=18 |issue=01 |pages=27–38 |doi=10.24071/llt.2015.180104 |issn=1410-7201|doi-access=free }} For instance, "The king of France is not bald" likewise presupposes that there is a king of France.