guessed at, but by the effect it outwardly produces. In a machine so extremely complex as man, formed by the combination of such a multiplicity of matter, so diversified in its properties, so different in its proportions, so varied in its modes of action, the motion necessarily becomes of the most complicated kind; its dullness, as well as its rapidity, frequently escapes the observation of those themselves, in whom it takes place.
Let us not, then, be surprised, if, when man would account to himself for his existence, for his manner of acting, finding so many obstacles to encounter, he invented such strange hypotheses to explain the concealed spring of his machine — if then this motion appeared to him, to be different from that of other bodies, he conceived an idea, that he moved and acted in a manner altogether distinct from the other beings in Nature. He clearly perceived that his body, as well as different parts of it, did act; but, frequently, he was unable to discover what brought them into action: from whence he received the impulse: he then conjectured he contained within himself a moving principle distinguished from his machine, which secretly gave an impulse to the springs which set this machine in motion; that moved him by its own natural energy; that consequently he acted according to laws totally distinct from those which regulated the motion of other beings: he was conscious of certain internal motion, which he could not help feeling; but how could he conceive, that this invisible motion was so frequently competent to produce such striking effects? How could he comprehend, that a fugitive idea, an imperceptible act of thought, was so frequently capacitated to bring his
