ratiocination

A 19th-century portrait of English philosopher John Stuart Mill (1806–1873). In his work A System of Logic, Ratiocinative and Inductive (1843), Mill distinguished induction from ratiocination, and developed five principles of inductive reasoning now known as Mill’s Methods.

Borrowed from French ratiocination, from Latin ratiōcinātiō (“argumentation, reasoning, ratiocination; a syllogism”), from ratiōcinātus (“reckoned”) + -tiō (“suffix forming a noun relating to some action or the result of an action”). Ratiōcinātus is the perfect passive participle of ratiōcinor (“to compute, reckon; to argue, infer”), from ratiō (“reason, explanation”) (from reor (“to calculate, reckon”), possibly from Proto-Italic *rēōr, from Proto-Indo-European *h₂reh₁- (“to put in order”)) +‎ -cinor, modelled after vāticinor (“to foretell, prophesy”), equivalent to ratiocinate +‎ -ion.

• (Received Pronunciation) IPA^(key): /ɹætɪˌɒsɪˈneɪʃn̩/
• (General American) IPA^(key): /ɹætiˌɑsiˈneɪʃn̩/, /ɹæʃi-/
• Hyphenation: ra‧ti‧o‧ci‧na‧tion

ratiocination (usually uncountable, plural ratiocinations)

1. Reasoning, conscious deliberate inference; the activity or process of reasoning.
   • 1658, [Blaise Pascal]; transl. sometimes attributed to John Evelyn, “The Answer of a Certain Apologist for the Jesuits to the XII. Letter, Refuted”, in Les Provinciales, or, The Mystery of Jesvitisme. Discovered in Certain Letters, Written upon Occasion of the Present Differences at Sorbonne, between the Jansenists and the Molinists: Displaying the Pernicious Maximes of the late Casuists, 2nd corrected edition, London: Printed for Richard Royston, and are to be sold by Robert Clavell, at the Stags-Head neer St. Gregories Church in St. Pauls Church-yard, OCLC 11086058, page 196:

     But it will be apparent from the refutation of the ſecond Falſification, wherewith you charge the Author of the Letters, that theſe miſchievous conſequences are rightly drawn from the wicked principle layd down by Vaſquez [Gabriel Vásquez] in the ſame place, and accordingly, that that Jeſuit hath not done violence to the rules of ratiocination, but to thoſe of the Goſpel.

   • 1663, Samuel Butler, Hudibras. The First Part. Written in the Time of the Late Wars, London: Printed by J. G. for Richard Marriot [...], OCLC 4023163; republished as Hudibras. In Three Parts. Written in the Time of the Late Wars. Corrected and Amended: with Additions. To which is Added Annotations, with an Exact Index to the Whole. Adorn’d with a New Set of Cuts, from the Designs of Mr. [William] Hogarth, Dublin: Printed by S. Powell, for R. Gunne, G. Risk, G. Ewing, and W. Smith, 1732, OCLC 938431277, canto I, lines 77–80, page 20:

     He'd run in Debt by Diſputation, / And pay with Ratiocination. / All this by Syllogiſm, true / In Mood and Figure, he wou'd do.

   • 1843, John Stuart Mill, “Of Inference, or Reasoning, in General”, in A System of Logic, Ratiocinative and Inductive, being a Connected View of the Principles of Evidence, and the Methods of Scientific Investigation. [...] In Two Volumes, volume I, London: John W[illiam] Parker, West Strand, OCLC 156109929, § 3, page 223:

     Reasoning, in the extended sense in which I use the term, and in which it is synonymous with Inference, is popularly said to be of two kinds: reasoning from particulars to generals, and reasoning from generals to particulars; the former being called Induction, the latter Ratiocination or Syllogism. […] The meaning intended by these expressions is, that Induction is inferring a proposition from propositions less general than itself, and Ratiocination is inferring a proposition from propositions equally or more general.

   • 1916 June 8, “Suffrage at Chicago”, in The New York Times‎:

     It is hard to follow the kinks of woman suffrage ratiocination.

   • 1965, Lewis A. Coser, The Nation, volume 201, New York, N.Y.: J. H. Richards, ISSN 0027-8378, OCLC 878983297, page 166, column 2; republished as “Anti-intellectualism”, in A Handful of Thistles: Collected Papers in Moral Conviction, New Brunswick, N.J.: Transaction Books, 1988, →ISBN, page 149:

     As the requirements of mass democracy forced the gentleman intellectual from the political scene, the new style political leaders felt the need to flatter the electorate by stressing the superiority of inborn, natural, intuitive and folkish wisdom and to devaluate the ratiocinations of the cultivated.

2. Thought or reasoning that is exact, valid and rational.
   • 1913, Paul Carus, “Introduction”, in Lao-tze; Paul Carus, transl., The Canon of Reason and Virtue: 老子 道德經: Being Lao-tze’s Tao Teh King: Chinese and English, Chicago, Ill.: Open Court Publishing Company, OCLC 832824001, pages 14–15:

     Finally Tao comes to possess the meaning of “rational speech” or “word,” and in this sense it closely resembles the Greek Logos, for in addition to its philosophical significance the term Tao touches a religious chord in the souls of the Chinese just as did the word Logos among the Platonists and the Greek Christians. […] The Tao of man, jan tao [footnote: 人道], is the process of ratiocination, and as such it is fallible; but there is an Eternal Reason, ch‘ang tao [footnote: 常道], also called t‘ien tao [footnote: 天道], “Heaven’s Reason,” i.e., the world-order which shapes all things, and the burden of Lao-tze’s message is to let this Heaven’s Reason or Eternal Reason prevail.

3. A proposition arrived at by such thought.
   • 1975, C[lifford] E[dmund] Bosworth, “Foreword”, in Imam Nawawi; Muhammad Zafrulla Khan, transl., Gardens of the Righteous: Riyadh as-Salihin, Abingdon, Oxon.: Published with the permission of Routledge by Islam International Publications Limited, published 2007, →ISBN, page vii:

     Where the Qur’an has not been explicit, the Hadith has often supplied guidance, providing an intermediate source of knowledge between the text of the Holy Book itself and the ratiocinations of the religious lawyers, the fuqaha’, who had recourse, when all else failed, to such principles as analogical reasoning and personal judgement.

• reasoning

• ratiocinate
• ratiocinative
• ratiocinatively
• ratiocinator
• ratiocinatory

• logic
• syllogism

• “ratiocination” in The Oxford English Dictionary, 2nd edition, Oxford: Clarendon Press, 1989, →ISBN.

• reason on Wikipedia.Wikipedia
• ratiocination in The Century Dictionary, New York, N.Y.: The Century Co., 1911.
• ratiocination in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913.