| 释义 |
dichotomy|daɪˈkɒtəmɪ|
[ad. Gr. διχοτοµία a cutting in two, f. διχότοµ-ος (see dichotomous): cf. F. dichotomie (1754 in Hatz.-Darm.).]
1. Division of a whole into two parts.
a. spec. in Logic, etc.: Division of a class or genus into two lower mutually exclusive classes or genera; binary classification.
1610Healey St. Aug. Citie of God 303 This Trichotomy..doth not contradict the other Dichotomy that includeth all in action and contemplation. 1725Watts Logic i. vi. §8 Some.. have disturbed the Order of Nature..by an Affectation of Dichotomies, Trichotomies, Sevens, Twelves, &c. Let the Nature of the Subject, considered together with the Design which you have in view, always determine the Number of Parts into which you divide it. 1864Bowen Logic iv. 97 Convenience often requires what Logicians call division by dichotomy, in which a Genus is divided into two Species having Contradictory Marks. 1877E. Caird Philos. Kant ii. vi. 302 The whole sphere of reality may be divided in relation to any predicate..in what is called dichotomy by contradiction, e.g. that ‘everything must either be red or not red’.
b. gen. Division into two. Something divided into two or resulting from such a division; something paradoxical or ambivalent.
1636Featly Clavis Myst. xxi. 277 Whose day after a ramisticall dichotomy being divided into forenoone and afternoone. 1668Wilkins Real Char. ii. vii. §3. 190 The way of Dichotomy or Bipartition being the most natural and easie kind of Division. 1868Contemp. Rev. Apr. 598 Popular theology is rather founded on the dichotomy of man into body and soul, than on the Christian trichotomy of body, soul, and spirit. 1942N.Y. Times 28 Nov. 12/4 ‘An absolute dichotomy between science and reason on the one hand and faith and poetry on the other.’ In other and simpler days people spoke of the conflict between science and religion, or the clash between the two, or the wide gulf between the two. 1950Listener 28 Sept. 430/1 The questions of thinking in one language and writing in another, the doubtful dichotomy of east and west. 1957‘J. Wyndham’ Midwich Cuckoos xiii. 105 By a dichotomy familiar to us all, a woman requires her own baby to be perfectly normal, and at the same time superior to all other babies. 1966Listener 3 Mar. 323/2 Their uncritical use of the ‘Communist’ versus ‘free world’ dichotomy.
2. Astron. That phase of the moon (or of an inferior planet) at which exactly half the disk appears illuminated; the ‘half-moon’.
1686Goad Celest. Bodies i. xv. 81 This Quadrate or Quartile in its Dichotomy, as the Greeks call it. 1797Encycl. Brit. II. 419/1 Aristarchus..gave a method of determining the distance of the sun by the moon's dichotomy. 1878Newcomb Pop. Astron. 551 Dichotomy, the aspect of a planet when half illuminated.
3. Bot., Zool., etc. A form of branching in which each successive axis divides into two; repeated bifurcation: see dichotomous 2.
1707Sloane Jamaica I. 264 From the middle of the leaves rise one or two stalks..always divided into two, or observing a Dichotomy. 1835Kirby Hab. & Inst. Anim. II. xiii. 13 The last [Encrinus] seems to differ..in the dichotomies and length of the arms. 1880Gray Struct. Bot. iii. §3. 47 note, Dichotomy or forking, the division of an apex into two. 1882Vines Sachs' Bot. 169 Dichotomy..never produces structures..dissimilar to the producing structure; the divisions of a root produced by dichotomy are both roots, those of a leaf-bearing shoot both leaf-bearing shoots..dichotomy hence always falls under the conception of branching in the..narrower sense. Ibid. 464. |