On the other hand, the ego which knows is an acting ego. Its thought itself, properly speaking, and this display of science, are only one of the forms of its inner activity. It wills, and it must will. If the world acts on it by sensation, it acts incessantly on the world by its volitions. And let it not be said that the will simply represents a mechanical reaction of the ego, exactly equivalent to the action of the external world upon it,--that it is a simple transformation of energy,--for this is not true. Without here raising the question of liberty, it is certain that I do not give back in will simply what I have received under the form of sensation. I deliberate on the motives which urge me to act; I choose between them; I feel myself under obligation; I feel that I should will the good. It is impossible to conceive of moral action without the idea of end. I conceive it, therefore, under a different form from that of mechanical action. Responsibility and obligation are not less the necessary forms of will than logical necessity is the necessary form of thought. But soon there arises in man the most tragical of conflicts. Scientific determinism renders moral activity unintelligible, and moral activity comes into collision with the determinism of science. If mechanical determinism be absolutely true, my will is null; I am simply an automaton. If my responsibility is real, if my personal energy is not an illusion, there is in the world something besides matter, and, for man, there are other than mechanical laws. Thus divided in myself, I ought not to practise what I know, and I cannot do what I ought. I remain floating between a science which is not moral and a morality that I feel to be unscientific. My intellect destroys my will. As the one develops the other dies. The better I know the laws of the world the less reason I have for living and acting. My morality, at each act, gives the lie to my science, and my science, at each affirmation, refutes my morality. Such is the deep malady, the spiritual misery, of the best of our contemporaries. They feel that, with them, vital energy is in inverse proportion to the extent and penetration of thought. It is then that they declare that pessimism, a radical pessimism, is the truth; that existence, will, desire, are the chief evils, and that the supreme effort of science should be to cure us of them by delivering us from all our illusions; after which, in its turn, it will be extinguished itself, like a flame that has consumed the food on which it fed.