La langue des calculs, ouvrage posthume et élémentaire. . .

Condillac, Étienne Bonnot (1714-80). La langue des calculs, ouvrage posthume et élémentaire. . . . 2 vols. in 1, 12mo. [4], 233, [3]; [4], 252pp. Paris: Charles Houel, An VI [1797/8]. 173 x 96 mm. Tree sheep ca. 1797, corners a bit worn, flaw in front cover. Fine.

First 12mo Edition. A one-volume octavo edition was issued the same year, and the work also forms Vol. 23 of Condillac's Oeuvres. "It was through his last works-La logique and, especially, La langue des calculs-that Condillac exercised the most decisive influence on the philosophical taste of the generation of scientists immediately following his own. Therein, like his predecessors in the rationalist tradition, he looked to mathematics as the exemplar of knowledge. He parted company with them, however, in developing the preference he had expressed in his early work for the analytic over the synthetic mode of reasoning. Geometry had lent itself to the abuses of the framers of systems, and it was algebra that would exhibit how the operations of any proper science are only those of a 'well-made language.' Algebraic terms consist of a set of exact symbols. By convention they always mean the same thing. They are combined and manipulated according to rules of a perfectly exact syntax. Algebra, indeed, is at once a language and a method of analysis. By contrast, ordinary language is an inaccurate and clumsy instrument all rusted and corrupted by centuries of sophistry and superstition. To compare it with algebra would reveal the difference between science and the imperfections of life in society.

"In that comparison Condillac's philosophy entered into the reforming mission of the Enlightenment, the central imperative of the rationalism then having been to reduce the imperfections of human arrangements by approximating them to the natural and to educate the human understanding in the grammar of nature" (Dictionary of Scientific Biography).