Origin
Scalar implicatures typically arise where the speaker qualifies or scales their statement with language that conveys to the listener an inference or implicature that indicates that the speaker had reasons not to use a stronger, more informative, term. For example, where a speaker uses the term "some" in the statement, "Some students can afford a new car.", the use of "some" gives rise to an inference or implicature that "Not all students can afford a new car." As with pragmatic inference generally, such inferences are defeasible or cancellable – the inferred meaning may not be true, even though the literal meaning is true. This distinguishes such inferences from entailment. They are also non-detachable. A conversational implicature is said to be ''non-detachable'' when, after the replacement of what is said with another expression with the same literal meaning, the same conversational implicature remains. This distinguishes them from conventional implicatures. In a 2006 experiment with Greek-speaking five-year-olds' interpretation of aspectual expressions, the results revealed that children have limited success in deriving scalar implicatures from the use of aspectual verbs such as "start" (which implicates non-completion). However, the tested children succeed in deriving scalar implicatures with discrete degree modifiers such as "half" as in half finished. Their ability to spontaneously compute scalar implicatures was greater than their ability to judge the pragmatic appropriateness of scalar statements. In addition, the tested children were able to suspend scalar implicatures in environments where they were not supported. Griceans attempt to explain these implicatures in terms of the maxim of quantity, according to which one is to be just as informative as required. The idea is that if the speaker were in a position to make the stronger statement, they would have. Since they did not, they must believe that the stronger statement is not true.Grammatical approach
The most recent linguistic debate has witnessed the emergence of a so-called grammatical approach to scalar implicature. One version of this view posits that scalar structures are associated with an obligatorily articulated exhaustivity operator, which is responsible for the derivation. Supporting arguments for this view include embeddability, that is, the possible generation of scalar implicatures in the scope of logical operators, and contextual blindness, that is, the possible generation of scalar implicatures when in conflict with contextual information, including with contextually empty domains.Examples
Some examples of scalar implicaturetaken from Carston (p. 1) and Levinson (p. 136) are: :1a. Bill has got some of Chomsky's papers. :1b. The speaker believes that Bill hasn't got all of Chomsky's papers. :2a. There will be five of us for dinner tonight. :2b. There won't be more than five of us for dinner tonight. :3a. She won't necessarily get the job. :3b. She will possibly get the job. :4a. The Russians or the Americans have just landed on Mars. :4b. Not both of them have just landed on Mars. Uttering the sentence (a) in most cases will communicate the assumption in (b). This seems to be because the speaker did not use stronger terms such as 'there will be ''more'' than five people for dinner tonight' or 'she ''can't possibly'' get the job'. For example, if Bill really did have all of Chomsky's papers, the speaker would have said so. However, according to the maxim of quantity, a speaker will only be informative as is required, and will therefore not use any stronger terms unless required. The hearer, knowing this, will assume that the stronger term does not apply.See also
* Cooperative principle * Downward entailing * Focus (linguistics) *References
* Robyn Carston, "Informativeness, Relevance and Scalar ImplicatureEndnotes
{{Formal semantics Pragmatics Semantics Inference Formal semantics (natural language)