Also 7–9 enthymem; in Lat. form enthymema. [ad. L. enthȳmēma, a. Gr. ἐνθύμημα, f. ἐνθῡμέεσθαι to think, consider, infer, f. ἐν in + θῡμός mind.]
† 1. Rhet. After Aristotle’s use: An argument based on merely probable grounds; a rhetorical argument as distinguished from a demonstrative one. Obs.
1600. Holland, Livy, XXIII. xii. 481. These strange Enthymemes and conclusions.
1642. Milton, Apol. Smect. (1851), 256. To wreath an Enthymema with maistrous dexterity.
a. 1677. Barrow, Serm. (1686), III. ii. 18. Oratours back their Enthymemes (or rational Argumentations) with Inductions (or singular Examples).
1841. De Quincey, Rhetoric, Wks. X. (1862), 27. [Explains Aristotle’s use, as distinguished from that of later logicians].
† 2. Cicero (Top. xiii.) uses enthymema for a striking antithesis closing a rhetorical period. Hence the following definitions:
1657. J. Smith, Myst. Rhet. (1665), 242. An Enthymem … is, as Cicero saith, when the sentence concluded consisteth of contraries.
1731. Bailey, Enthymem (with Rhetoricians) is when the concluding sentence consists of contraries.
3. Logic. A syllogism in which one premiss is suppressed.
[This sense is due to a misapprehension (already in Boethius a. 524), the description of the enthymeme (sense 1) as ‘an imperfect syllogism’ (άτελὴς συλλογισμός) having been interpreted as referring to its form instead of its matter.]
1588. Fraunce, Lawiers Log., II. ix. 98 b. An Enthymeme is nothing but a contracted syllogisme.
1656. Cowley, Pindar. Odes, 50, note. In Enthymemes … half is left out to be supplyed by the Hearer.
1712. Arbuthnot, John Bull (1755), 95. I desire to know whether you will have it by way of Syllogism, Enthymem, Dilemma, or Sorites.
1764. Reid, Inquiry, i. § 3. 16. Perhaps Des Cartes meant not to assume his own existence in this enthymeme, but the existence of thought.
1795. Wythe, Decis. Virginia, 15. The argument included in this opinion is an enthymema.
1827–36. Whately, Logic, 265. In an Enthymeme the suppressed Premiss should be always the one of whose truth least doubt can exist.
1870. Bowen, Logic, iii. 57. The common form of argumentation is Enthymeme, which consists of but two propositions.
