Also 7 -ie, -ee. [ad. late L. theōria (Jerome in Ezech. XII. xl. 4), a. Gr. θεωρία a looking at, viewing, contemplation, speculation, theory, also a sight, a spectacle, abstr. sb. f. θεωρός (:—*θεαορός) spectator, looker on, f. stem θεα- of θεᾶσθαι to look on, view, contemplate. In mod. use prob. from med.L. transl. of Aristotle. Cf. It. teoria (Florio, 1598, theoría), F. théorie (15[?] in Godef., Compl.).]
† 1. A sight, a spectacle. Obs. rare.
1605. Bp. Andrewes, Serm., Passion (1631), 365. Saint Luke … calleth the Passion θεωρίαν a Theory or Sight…. Of our blessed Saviour’s whole life or death, there is no part but is a Theorie of it selfe, well worthie our looking on.
† 2. Mental view, contemplation. Obs.
[1598–1611. Florio, Theoría, contemplation, speculation, deepe study, insight or beholding.]
1611. Cotgr., Theorie, theorie, contemplation, deepe studie; a sight, or beholding, speculation.
1643. Sir T. Browne, Relig. Med., I. § 45. Nor can I thinke I have the true Theory of death when I contemplate a skull, or behold a Skeleton with those vulgar imaginations it casts upon us. Ibid. (1646), Pseud. Ep., VII. xix. 385. As they encrease the hatred of vice in some, so doe they enlarge the theory of wickednesse in all.
1653. W. Harvey, Anat. Exercit., Pref. ¶ v. All their theory and contemplation (which they count Science) represents nothing but waking mens dreams, and sick mens phrensies.
1710. Norris, Chr. Prud., ii. 65. Speculative Knowledge contemplates Truth for itself, and accordingly stops and rests in the Contemplation of it, which is what we commonly call Theory.
3. A conception or mental scheme of something to be done, or of the method of doing it; a systematic statement of rules or principles to be followed.
1597. Hooker, Eccl. Pol., V. xxix. § 8. If they had been themselves to execute their owne Theorie in this Church.
1643. Bp. Hall, Devout Soul, i. It will hardly be believed, how far some of their contemplative men have gone in the theory hereof.
1674. Dryden, Prol. Univ. Oxford, 11. Your theories are here to practice brought, As in mechanic operations wrought.
1798. Malthus, Popul., III. ii. (1806), II. 103. A theory that will not admit of application cannot possibly be just.
1832. Austin, Jurispr. (1879), II. 1133. Theory of what is and theory of what ought to be are perpetually confounded.
1853. Bright, Sp. India, 3 June (1876), 4. The theory of the old Government of India was one which could not be defended.
1879. M. Pattison, Milton, xiii. 219. Even the calm and gentle author of the Christian Year … deliberately framed a theory of Poetic for the express purpose, as it would seem, of excluding the author of Paradise Lost from the first class of poets.
4. A scheme or system of ideas or statements held as an explanation or account of a group of facts or phenomena; a hypothesis that has been confirmed or established by observation or experiment, and is propounded or accepted as accounting for the known facts; a statement of what are held to be the general laws, principles, or causes of something known or observed.
1638. Sir T. Herbert, Trav. (ed. 2), 127. Or whether from subterranean fires,… I dare not conclude, but leave such theories to those that study Meteors.
1684. Burnet (title), The Theory of the Earth.
1706. Phillips (ed. Kersey), Theories of the Planets, certain Hypotheses, or Suppositions about the Motions of the Heavens, according to which, Astronomers explain … the Phænomena or Appearances of the Planets.
1727–41. Chambers, Cycl., s.v., We say … theory of the rainbow, of the microscope … the motion of the heart, the operation of purgatives, etc.
1812. Playfair, Nat. Phil. (1819), I. 3. A theory is often nothing else but a contrivance for comprehending a certain number of facts under one expression.
1850. Grove, Corr. Phys. Forces (ed. 2), 105. Were a theory open to no objection it would cease to be a theory, and would become a law.
1879. M. Pattison, Milton, xiii. 180. The Copernican theory, which placed the sun in the centre of our system, was already the established belief of the few well-informed.
1890. A. R. Wallace, Darwinism, 7. The truest and most complete theory would not enable us to solve all the difficult problems which the whole course of the development of life upon our globe presents to us.
b. That department of an art or technical subject which consists in the knowledge or statement of the facts on which it depends, or of its principles or methods, as distinguished from the practice of it.
1613. R. Cawdrey, Table Alph. (ed. 3), Theorie, the contemplation, or inward knowledge of any art.
1626. Bacon, Sylva, § 327. The means, hitherto propounded, to effect it, are in the practice, full of error and imposture, and in the theory, full of unsound imaginations.
1660. R. Coke, Power & Subj., Pref. 5. A Musitian, who Composes well, yet understands but little in the theory of Musick.
1795. Hutton, Math. Dict., s.v., To be learned in an art, &c., the Theory is sufficient; to be a master of it, both the Theory and practice are requisite.
1827. Whately, Logic (ed. 2), 205. Logic being concerned with the theory of Reasoning.
1884. Grove, Dict. Mus., IV. 101/1. Theory, a term often used … to express the knowledge of Harmony, Counter-point, Thorough-bass, etc., as distinguished from the art of playing, which is … called ‘Practice.’
c. A systematic statement of the general principles or laws of some branch of mathematics; a set of theorems forming a connected system: as the theory of equations, of functions, of numbers, of probabilities.
1799. W. Frend (title), The Principles of Algebra…; or the true Theory of Equations established by mathematical demonstration.
1806. [see THEOREM a].
1811. P. Barlow (title), An Elementary Investigation of the Theory of Numbers.
1838. [see PROBABILITY 3].
1893. Forsyth (title), Theory of Functions.
5. In the abstract (without article): Systematic conception or statement of the principles of something; abstract knowledge, or the formulation of it: often used as implying more or less unsupported hypothesis (cf. 6): distinguished from or opposed to practice (cf. 4 b). In theory (formerly in the theory): according to theory, theoretically (opp. to in practice or in fact).
1624. T. Macarnesse, in Capt. Smith, Virginia, Pref. That thou mightst read and know and safely see, What he by practice, thou by Theoree.
1692. Sir W. Hope, Fencing-Master (ed. 2), 164. Theorie without Practice will serve but for little.
1769–72. Junius Lett., Pref. (1820), 17. Theory is at variance with practise.
1776. J. Adams, Wks. (1854), IX. 375. It is certain, in theory, that the only moral foundation of government is, the consent of the people.
1821. J. Q. Adams, in Davies, Metr. Syst., III. (1871), 175. A compromise between philosophical theory and inveterate popular habits.
6. In loose or general sense: A hypothesis proposed as an explanation; hence, a mere hypothesis, speculation, conjecture; an idea or set of ideas about something; an individual view or notion. Cf. 4.
1792. Burke, Corr. (1844), IV. 13. Whether I am right in the theory or not,… the fact is as I state it.
1794. Paley, Evid. (1825), II. 347. Theories which have, at different times, gained possession of the public mind.
1829. Jas. Mill, Hum. Mind (1869), II. xxv. 403. The word theory has been perverted to denote an operation … which … consists in supposing and setting down matters supposed as matters observed. Theory in fact has been confounded with Hypothesis.
1864. Bowen, Logic, xi. (1870), 375. A Theory, sometimes incorrectly used as a synonyme for Hypothesis.
1867. Lady Herbert, Cradle L., iii. 95. So varied are the theories as to the origin of these wonderful sepulchres.
1880. T. A. Spalding, Eliz. Demonol., 35. This was not a mere theory, but a vital active belief.
7. Comb., as theory-bigoted adj., -building, -monger, -spinning; theory-blind a., (a) blinded by a theory, so as to be unable to see the facts truly; (b) blind to a theory, i.e., unable to see or apprehend it (cf. color-blind); theory-man (nonce-wd.), a theorist; theory-tailor, contemptuously for a shaper of theories.
1884. Q. Rev., April, 337. More *theory-bigoted than Mr. ——.
1892. W. S. Lilly, Gt. Enigma, 230. You cannot help recognising, unless you are *theory-blind,… the law of correlation.
1902. Q. Rev., April, 359. No one who is not theory-blind—a very common form of blindness.
1780. Mirror, No. 107, ¶ 2. There is something … so delightful in this art of *theory-building.
1727. De Foe, Syst. Magic, I. i. (1840), 9. What our learned *theory-men insist to have been the causes of the deluge.
1905. Academy, 4 Feb., 105/1. It is high time that protest be made … against the master’s works being made the prey of *theorymongers.
1904. Windle, Prehist. Age, Pref. 13. There has been a vast amount of *theory-spinning in connexion with the early epochs.
1876. Meredith, Beauch. Career, xxxvii. These men are *theory-tailors not politicians.
