[177] The writers about 'unconscious cerebration' seem sometimes to mean that and sometimes unconscious thought. The arguments which follow are culled from various quarters. The reader will find them most systematically urged by E. von Hartmann: Philosophy of the Unconscious, vol. i; and by E. Colsenet: La Vie Inconsciente de l'Esprit (1880). Consult also T. Laycock: Mind and Brain, vol. i, chap. v (1860); W. B. Carpenter: Mental Physiology, chap. xiii; F. P. Cobbe: Darwinism in Morals and other Essays, essay xi, Unconscious Cerebration (1872); F. Bowen: Modern Philosophy, pp. 428-480; R. H. Hutton: Contemporary Review, vol. xxiv, p. 201; J. S. Mill: Exam. of Hamilton, chap. xv; G. H. Lewes: Problems of Life and Mind, 3d series, Prob. ii, chap. x, and also Prob. iii, chap. ii; D. G. Thompson: A System of Psychology, chap. xxxiii; J. M. Baldwin, Handbook of Psychology, chap. iv. [178] Nouveaux Essais, Avant-propos. [179] J. S. Mill, Exam. of Hamilton, chap. xv. [180] Cf. Dugald Stewart, Elements, chap. ii. [181] J. E. Maude: 'The Unconscious in Education,' in 'Education,' vol. i, p. 401 (1882). [182] Zur Lehre vor Lichtsinne (1878). [183] Cf. Wundt: Ueber den Einfluss der Philosophie, etc.--Antrittsrede (1876), pp. 10-11;--Helmholtz: Die Thatsachen in der Wahrnehmung (1879), p. 27. [184] Cf. Satz vom Grunde, pp. 59-65. Compare also F. Zöllner's Natur der Kometen, pp. 342 ff. and 425. [185] Cf. the statements from Helmholtz to be found later in Chapter XIII. [186] The text was written before Professor Lipps's Grundtatsachen des Seelenlebens (1883) came into my hands. In Chapter III of that book the notion of unconscious thought is subjected to the clearest and most searching criticism which it has yet received. Some passages are so similar to what I have myself written that I must quote them in a note. After proving that dimness and clearness, incompleteness and completeness do not pertain to a state of mind _as such_--since every state of mind must be _exactly_ what it is, and nothing else--but only pertain to the way in which states of mind stand for objects, which they more or less dimly, more or less clearly, _represent_; Lipps takes the case of those sensations which attention is said to make more clear. "I perceive an object," he says, "now in clear daylight, and again at night. Call the content of the day-perception _a_, and that of the evening-perception _a^1_. There will probably be a considerable difference between _a_ and _a^1_. The colors of _a_ will be varied and intense, and will be sharply bounded by each other; those of _a^1_ will be less luminous, and less strongly contrasted, and will approach a common gray or brown, and merge more into each other. Both percepts, however, as such, are completely determinate and distinct from all others. The colors of _a^1_ appear before my eye neither more nor less decidedly dark and blurred than the colors of _a_ appear bright and sharply bounded.