Must/need, may/can and the scope of the modal auxiliary

Abstract

Abstract This article argues that the logical paraphrases used to describe the meanings of must, need, may, and can obscure the natural-language semantic interaction between these verbs and negation. The purported non-negatability of must is argued to be an illusion created by the indicative-mood paraphrase ‘is necessary’, which treats the necessity as a reality rather than a non-reality. It is proposed that negation coalesces with the modality that must itself expresses to produce a negatively-charged version of must’s modality: the subject of musn’t is represented as being in a state of constraint in which the only possibility open to the subject is oriented in the opposite direction to the realization of the infinitive’s event. The study also constitutes an argument against a lexicalization analysis: in the combination mustn’t, must and not each contribute their own meaning to the resultant sense, but according to their conceptual status as inherently irrealis notions.