To understand, observe, and draw conclusions, man must first of all be conscious of himself as living. A man is only conscious of himself as a living being by the fact that he wills, that is, is conscious of his volition. But his will—which forms the essence of his life—man recognizes (and can but recognize) as free.
If, observing himself, man sees that his will is always directed by one and the same law (whether he observes the necessity of taking food, using his brain, or anything else) he cannot recognize this never-varying direction of his will otherwise than as a limitation of it. Were it not free it could not be limited. A man’s will seems to him to be limited just because he is not conscious of it except as free.
You say: I am not free. But I have lifted my hand and let it fall. Everyone understands that this illogical reply is an irrefutable demonstration of freedom.
That reply is the expression of