Condillac, ÉTIENNE BONNOT DE MABLY DE, philosopher, was born of a noble family at Grenoble, 30th September 1715. His life was uneventful. As a child his delicate health delayed his progress in education; but in youth he numbered among his friends Rousseau, Diderot, Duclos, &c. Many of his works were composed for his pupil, the Duke of Parma, grandson of Louis XIV.; and he was titular Abbé de Mureaux. He was chosen a member of the French Academy of Sciences in 1768. He died on his estate of Flux, near Beaugency, on August 3, 1780.
A great part of the Essai sur l'Origine des Connaissances Humaines (1746), and nearly all the Traité des Systèmes (1749), are occupied with a polemic against innate ideas and abstract systems. He expounds his analytic method in the Logique (1780) and the Art de Raisonner (part of the Cours d'Études, in 13 vols. 1755). The Langue des Cæcils appeared in 1798.
In the Traité des Sensations, Condillac uses his analytic method to solve the problem of the origin of our ideas and the formation of the mental faculties. He divided philosophical systems into three classes—(1) Abstract systems, (2) hypothesis, (3) the 'true' system of Locke, which rests on the facts of experience. But in confounding sensation and perception, and endeavouring to base all thought on sensation, he departed from Locke, and became the founder of Sensationalism. To Condillac all reasoning is only a variation of the form of expression. He held that all ideas and mental operations are only transformations of sensation. So he was compelled to put into the primary sensation all that he sought to develop out of it. His curious device of the statue, gradually endowed with the various senses and mental faculties, was for the purpose of isolating sensations. He substituted for the Cartesian test of truth his own criterion of identity. He recognised three kinds of evidence—of fact, of feeling, and of reason; and he affirmed that the same method of analysis is common to all the sciences. Unlike his scholars and followers, the encyclopædists Diderot, D'Alembert, Holbach, Condillac was not a materialist.
Le Commerce et le Gouvernement, published in 1776, treats economy as the science of exchanges, and has much influenced later economists. Condillac was a strong believer in Free Trade. The first of several editions of his Œuvres Complètes appeared in 1798. See monographs by Robert (Paris, 1869) and Réthori (1864), and Lewes's History of Philosophy.