He first shows that the study of psychology reveals to us the human powers of sensation, feeling and will. These are the immediate data of consciousness. Another element, however, enters into consciousness, not as these three, a definite content, but as a colouring of the whole. This other element is “objectivity,” an awareness or belief that the world without exists and continues to exist independently of our observation of it. Lachelier combats, however, the Kantian conception of the “thing-in-itself.” If, he argues, the world around us appears as a reality which is independent of our perception, it is _not_ because it is a “thing-in-itself,” but rather it appears as independent because we, possessing conscious intelligence, succeed in making it an object of our thought, and thus save it from the mere subjectivity which characterises our sense-experience. It is upon this fact, Lachelier rightly insists, that all our science reposes. A theory of knowledge as proposed by Taine, based solely on sensation and professing belief in _hallucination vraie_, is itself a contradiction and an abuse of language. “If thought is an illusion,” remarks Lachelier, “we must suppress all the sciences.”[30] [30] _Psychologie et Métaphisique_, p.151.(See especially the passages on pp.150-158.) He then proceeds to show that if we admit thought to be the basis of our knowledge of the world, that is, of our sciences, then we admit that our sciences are themselves connstructions, based upon a synthetic, constructive, creative activity of our mind or spirit. For our thought is not merely another “thing” added to the world of things outside us. Our thought is not a given and predetermined datum, it is “a living dialectic,” a creative activity, a self-creative process, which is synthetic, and not merely analytic in character. “Thought,” he says, “can rest upon itself, while everything else can only rest upon it; the ultimate _point d’appui_ of all truth and of all existence is to be found in the absolute spontaneity of the spirit.”[31] Here, Lachelier maintains, lies the real _a priori_; here, too, is the very important passage from psychology to metaphysics. [31] _Psychologie et Métaphysique_, p. 158.