Enthymeme

An enthymeme (Greek: ἐνθύμημα, enthumēma), in its modern sense, is an informally stated syllogism (a three-part deductive argument) with an unstated assumption that must be true for the premises to lead to the conclusion. In an enthymeme, part of the argument is missing because it is assumed. In a broader usage, the term "enthymeme" is sometimes used to describe an incomplete argument of forms other than the syllogism, or a less-than-100% argument. For Aristotle, who defined it in his Rhetoric, an enthymeme was a "rhetorical syllogism" which was based on probable opinions, thus distinguishing it from a scientific syllogism. It is aimed at persuasion while scientific syllogism is aimed at demonstration. This definition of an enthymeme held fast until the 20th century, when Saul Kripke developed Modal logic. In the context of Modal logic, with Semantic tableaux as developed by Evert Willem Beth, the definition of an enthymeme alters: Rather than suppressing one of the major premises, minor premises, or the conclusion, any incorrect logical inference or proof that is persuasive, satisfies a concept of an enthymeme.