a. (sb.) [ad. L. syllogisticus (Quintilian) or Gr. συλλογιστικός, f. συλλογίζεσθαι to SYLLOGIZE: see -IC and -ISTIC. Cf. F. syllogistique, Ital. sillo-, silogistico, etc.] Of, pertaining to, of the nature of, or consisting of a syllogism or syllogisms.
1669. Gale, Crt. Gentiles, I. I. ii. § 14. The more simple mode of philosophizing by Dialogues,… which was the main Logic used in al the Grecian … Scholes, before Aristotle brought in the syllogistic forme of Mode and Figure.
1678. Cudworth, Intell. Syst., I. v. 770. To put the Argument into a more Approveable Syllogistick Form, Whatsoever is Extended, is Body, or Corporeal; But Whatsoever is, is Extended. Therefore Whatsoever Is, is Body, or Corporeal. And by Consequence there can be no Incorporeal Deity.
1697. trans. Burgersdicius’ Logick, II. vi. 22. The Syllogistick Form is only an apt Disposition of the three Propositions for the necessary Collection of a Conclusion from the Premisses.
1751. Johnson, Rambler, No. 152, ¶ 10. If a disputed position is to be established, or a remote principle to be investigated, he may detail his reasonings with all the nicety of syllogistic method.
1821. Aldrich’s Artis Logicæ Rudim. (ed. 2), 110. The harshness and apparent tautology of the formal syllogism has been one occasion of prejudice against the syllogistic system.
1855. Spencer, Princ. Psychol., II. VI. vii. 73. So-called syllogistic reasoning passes into what is commonly known as reasoning by analogy.
1867. Fowler, Deduct. Logic, III. iii. 90. We shall first enumerate and explain certain syllogistic rules (derived from the definition of a syllogism) which will exclude illegitimate moods.
B. sb. Reasoning by syllogisms; that department of logic that deals with syllogisms. Also pl. (see -ICS). rare.
1833. Sir W. Hamilton, Discuss. (1853), 135. Dr. Whately makes the process of reasoning not merely its [sc. logic’s] principal, but even its adequate object;… In this view Logic is made convertible with Syllogistic.
1837. Carlyle, Fr. Rev., III. II. v. The rest … welter amid Law of Nations, Social Contract, Juristics, Syllogistics.
1847. Sir W. Hamilton, Lett. to De Morgan, 3. The principle of Syllogistic, afforded by the quantification—the expressed quantity—of the predicate.
