Etienne Bonnot De Condillac, a French philosopher, born at Grenoble, Sept. 30, 1715, died Aug. 3, 1780. In early youth his constitution was so feeble that he could not be kept at school; at 12 years of age he was not able to read. After having improved in health, he devoted himself to science, and became the tutor of the heir apparent of Parma, a nephew of Louis XV. Having completed the prince's education, he returned to Paris, and subsequently retired to an estate near Beaugency, where he spent the rest of his life. He was a quiet, unpretending scholar. In his philosophy he started from the ideas of Gassendi and Hobbes, and from the psychological researches of Locke, but enlarged and modified them to such a degree' that his claims to originality have not been seriously contested. His theories were highly esteemed for their clearness and simplicity, and were widely propagated by the encyclopaedists. In his Essai sur l'origine des connaissances liumaines (Amsterdam, 1746), he maintained the following propositions: 1. All our ideas originate in sensations; there are no innate ideas. 2. Not only our ideas but all faculties of the human soul proceed from transformed sensations; the intellectual faculties (attention, comparison, judgment, reflection, imagination, and the reasoning power) from sensations so far as they represent external objects; the faculties of volition (need, desire, passion, and resolution) from sensations so far as they affect the subject. 3. The intellectual action consists merely in the connection and combination of ideas. 4. Left to itself, unaided by the senses, the human mind is void and powerless.

Whatever progress it has made is owing to the use of signs and articulated sounds. Thinking is nothing without language. Languages are analytical methods. To them we owe most of our ideas, which have no reality except by the words or signs representing them. 5. In reasoning, proof is afforded by identity. The demonstration of such identity is facilitated by the close analogy of words. Hence science is not much more than language, and a correct science depends upon a correct language, adapted as closely as possible to the different modifications and gradations of perception. 6. The only method leading to the knowledge of truth is the analytic one, the close and logical observation of all parts of an object, so that the mind may comprehend them simultaneously, and understand their common principle. Synthesis, beginning with definitions and abstract generalities, is useless, since it generates chimeras and errors. Oon-dillac, although reducing all the faculties of the soul to mere transformations of sensation, does not belong to the materialist school proper. Unlike La Mettrie and his followers, he does not consider sensation as a mere physical process, and assumes the immaterial nature of the soul.

In his Traite des systemes (1749) he endeavored to show that all metaphysical systems are based upon arbitrary assumptions, shallow quibbles, or empty abstractions. The "innate ideas" of Descartes, the "ideas of God" of Malebranche, the "monads" of Leibnitz, the "infinite substance" of Spinoza, are all mercilessly dissected by Condillac, and exposed as chimeras. His Traite des sensations (1754) is an ingenious demonstration of the psychological process by which sensations are developed into ideas and self-consciousness. In this book Condillac exhibits a human form as yet entirely inanimate, and then adding successively the senses, he goes on to show what kind of sensations are produced by the one and the other; how by the repetition or combination of these sensations ideas are begot; again, how these ideas are interwoven, and new combinations formed, every succeeding one more remote from and apparently independent of the original sensitive impressions. The idea of considering the human mind first as a tabula rasa, and then observing the action of the senses upon it, was not entirely new; it had been used before by Bonnet, Diderot, and Buffon. The original manner, therefore, in which this idea had been used by Condillac did not save him from the reproach of having mechanically imitated Buffon. To show the untruth of this, he wrote his Traite des animaux (1755), in which he refuted many of Buffon's doctrines by the very principles laid down in the Traite des sensations.

While tutor of the prince of Parma, Condillac composed the Cours d'etudes, in three volumes, intended as a kind of cyclopaedia of philosophical and historical science, but chiefly remarkable for the ingenious investigation of the signs and words representing sensations and ideas. Another work, Le commerce et le gouvernement consideres relativement l'un d l'autre (1776), being an application of his analytic method to political and economical doctrines, was not successful. Having been requested by the board of education of Poland to assist in the organization of public education in that country, Condillac wrote his Logique (published in 1781), as a manual for schools. An incomplete work, La langue des calculs, in which he had proposed to demonstrate that all sciences might be rendered as positive and exact as mathematics, was published in 1798 by Laromiguiere. Several editions of the complete works of Condillac have been published in Paris (23 vols., 1798; 32 vols., 1803; 16 vols., 1821).