We turn next from the popular introduction and dissemination of Locke's doctrines, which left their contents unchanged, to their principiant development by the French sensationalists. Condillac (1715-80) always thinks of his work as a completion of Locke's, whose _Essay_ he held not to have gone down to the final root of the cognitive process. Locke did not go far enough, Condillac thinks, in his rejection of innate elements; he failed to trace out the origin of perception, reflection, cognition, and volition, as also the relation between the external senses, the internal sense, and the combining intellect, which he discussed as separate sources, the two former of particular, and the last of complex, ideas; in short, he omitted to inquire into the origin of the first function of the soul. Berkeley was right in feeling that a simplification was needed here; but by erroneously reducing outer perception to inner perception, he reached the absurd conclusion of denying the external world. The true course is just the opposite of this--the one already taken by the Bishop of Cork, Peter Browne (died 1735; _The Procedure, Extent, and Limits of the Human Understanding_, 1728): understanding and reflection must be reduced to sensation. All psychical functions are transformed sensations. The soul has only one original faculty, that of sensation; all the others, theoretical and practical alike, are acquired, _i.e._, they have gradually developed from the former. Condillac is related to Locke as Fichte to Kant; in the former case the transition is mediated by Browne, in the latter by Reinhold. Each crowns the work of his predecessor with a unifying conclusion; each demands and offers a genetic psychology which finds the origin of all the spiritual functions--from sensation and feelings of pleasure and pain up to rational cognition and moral will--in a single fundamental power of the soul. But there is a great difference, materially as well as formally, between these kindred undertakings, a difference corresponding to that between Locke's empiricism and Kant's idealism. The idea of ends, which controls the course of thought in Fichte as in Leibnitz, is entirely lacking in Condillac; that which is first in time, sensation, is for the Science of Knowledge and the Monadology only the beginning, not the essence, of psychical activity, while Condillac makes no distinction between beginning and ground, but expressly identifies _principe_ and _commencement_. With Fichte and Leibnitz sensation is immature thought, with Condillac thought is refined sensation. The former teach a teleological, the latter a mechanical mono-dynamism. The Science of Knowledge, moreover, makes a very serious task of the deduction of the particular psychical functions from the original power, while Condillac takes it extraordinarily easy. Good illustrations of his way of effacing distinctions instead of explaining them are given by such monotonously