JEVONS. 3 WORKS

i. Studies in deductive logic. A manual for students. London: Macmillan and Co., 1880, first edition, advertisements at the end, original cloth, foxed, covers worn at edges, (the philosopher Alfred Robinson (1841-1895), Bursar of New College, Oxford; Horace William Brindley Joseph (1867-1943), Robinson's successor as New College's Senior Philosophy Tutor, ownership signatures; bought from Bernard Quaritch, London, 2005), [not in T&W]ii. Pure logic and other minor works. London: Macmillan, 1890, original cloth, (bought from Stern, 1998), [T&W J19], binding worn at edges, upper hinge repaired, cracked, text slightly brownediii. The substitution of similars, the true principle of reasoning, derived from a modification of Aristotle's dictum. London: Macmillan, 1869, presentation copy inscribed "From the Author" on front endpaper, limp blue cloth, (bought from Librairie Alain Brieux, 1982) [T&W J21], somewhat worn 8vo (3)

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The third item is the work in which Jevons first describes his logical abacus. By the beginning of 1867 he had become convinced that "the great and universal principle of all reasoning" was the substitution of similars, and he set about writing his most important work, The Principles of Science, eventually published in 1874 (see previous lot). Meanwhile he published the shorter Substitution of Similars, which presents the essence of his ground-breaking system of logic.