[115] One of my colleagues, asking himself the question after reading the anecdote, tells me that he replied 'Harvard College,' the faculty of that body having voted, a few days previously, to keep back the degrees of members of the graduating class who might be disorderly on class-day night. W. J. [116] _Op. cit._ pp. 166-171. [117] The great maxim in pedagogy is to knit every new piece of knowledge on to a pre-existing curiosity--i.e., to assimilate its matter in some way to what is already known. Hence the advantage of "comparing all that is far off and foreign to something that is near home, of making the unknown plain by the example of the known, and of connecting all the instruction with the personal experience of the pupil.... If the teacher is to explain the distance of the sun from the earth, let him ask.... 'If anyone there in the sun fired off a cannon straight at you, what should you do?' 'Get out of the way' would be the answer. 'No need of that,' the teacher might reply. 'You may quietly go to sleep in your room, and get up again, you may wait till your confirmation-day, you may learn a trade, and grow as old as I am,--_then_ only will the cannon-ball be getting near, _then_ you may jump to one side! See, so great as that is the sun's distance!'" (K. Lange, Ueber Apperception, 1879, p. 76--a charming though prolix little work.) [118] A. Schopenhauer, Satz vom Grunde, chap. iv. H. Spencer, Psychol., part vi. chaps. ix, x. E. v. Hartmann, Phil. of the Unconscious (B), chaps. vii, viii. W. Wundt, Beiträge, pp. 422 ff.; Vorlesungen, iv, xiii. H. Helmholtz, Physiol. Optik, pp. 430, 447. A. Binet, Psychol. du Raisonnement, chaps. iii, v. Wundt and Helmholtz have more recently 'recanted.' See above, vol i. p. 169 note. [119] When not all M, but only some M, is A, when, in other words, M is 'undistributed' the conclusion is liable to error. Illusions would thus be _logical fallacies_, if true perceptions were valid syllogisms. They would draw false conclusions from undistributed middle terms. [120] See Spencer, Psychol., ii. p. 250, note, for a physiological hypothesis to account for this fact.