By modern psychologists the subject has been closely investigated. Professor G.F. Stout (Manual of Psychology, vol. ii. pp. 312 foll.) defines categories as “forms of cognitive consciousness, universal principles or relations presupposed either in all Modern psychologists. cognition or in all cognition of a certain kind.” He then treats External (or Physical) Reality, Space, Time, Causality and “Thinghood” from the standpoint of the perceptual consciousness; showing in what sense the categories of causality, substance and the rest exist in the sphere of perception. As contrasted with the ideational, the perceptual consciousness is concerned with practice. Perception tells the child of things as separate entities, not in their ultimate relations as parts of a coherent whole. G.T. Ladd (Psychology Descriptive and Explanatory, ch. xxi., on “Space, Time and Causality”) defines the categories from the psychological standpoint as “those highly abstract conceptions which the mind frames by reflection upon its own most general modes of behaviour. They are our own notions resulting from co-operation of imagination and judgment, concerning the ultimate and unanalyzable forms of our own existence and development.” In other words, the categories are highly abstract, have no content, and are realized as a kind of thinking which has for its object all the other mental processes.
Authorities.—Besides those quoted above, see Eduard v. Hartmann, Kategorienlehre (Leipzig, 1896), and “Begriff der Kategorialfunktion”, in Zeitschr. f. Philos. und phil. Krit. cxv. (1899), pp. 9-19; E. König in the same periodical cxiii. (1889), pp. 232-279, and cxiv. (1899), pp. 78-105; F.A. Trendelenburg, Geschichte der Kategorienlehre (1846); P. Ragnisco Storia critica delle categorie (2 vols., Florence, 1871); W. Windelband Vom System der Kategorien (Tübingen, 1900); R. Eisler, Wörterbuch der philospphischen Begriffe (Berlin, 1899), pp. 400-409; S. Joda, Studio critico su le categorie (Naples, 1881); H. Vaihinger, Die transcendentale Deduktion der Kategorien (Halle, 1902); H.W.B. Joseph, Introduction to Logic (Oxford, 1906), ch. iii.; F.H. Bradley, Principles of Logic (1883); B. Bosanquet’s Knowledge and Reality (1885, 2nd ed. 1892); histories of philosophy. For further authorities see works quoted under [Aristotle] and [Kant], and in J.M. Baldwin’s Dict. Philos. Psych. vol. iii. pt. 2, p. 685.
(R. Ad.; X.)
[1] For details of this and other Hindu systems see H. T. Colebrooke, Miscellaneous Essays (1837; new ed., E. B. Cowell, 1873); H. H. Wilson, Essays and Lectures on the Religions of the Hindus (1861-1862); Monier Williams, Indian Wisdom (4th ed., 1893); A. E. Gough’s Vaiseshika-Sutras (Benares, 1873), and Philosophy of the Upanishads (London, 1882, 1891); Max Müller, Sanskrit Literature, and particularly his appendix to Thomson’s Laws of Thought.
[2] The supposed origin of that theory in the treatise περὶ τοῦ παντός, ascribed to Archytas (q.v.), has been proved to be an error. The treatise itself dates in all probability from the Neo-Pythagorean schools of the 2nd century a.d.
[3] Prantl, Ges. der Logik, i. 74-75; F.A. Trendelenburg, Kategorienlehre, 209. n.
[4] Soph. 254 D.
[5] Against this passage even Prantl can raise no objection of any moment; see Ges. der Logik, i. 206. n.
[6] See Bonitz, Iridex Aristotelicus, s.v., and Prantl, Ges. der Logik, i. 207.