Innumerable times every day of his life he would like to break many or all of the Ten Commandments; but he abstains from so doing, and, what is more, mostly without effort, without having painfully to suppress his desire. What prevents him from yielding to his impulses? An invisible power which lays its commands upon him: "Thou shalt not!" "Thou shalt!" Often his aims and inclinations come into violent collision with this order, or this prohibition, and are hurled back by the painful impact. Man hears the threatening, imperious voice, but cannot see whence it comes. Accustomed to reason by analogy, he concludes that it is, like thunder, a voice of Nature. When the pike has sufficiently injured his nose against the pane of glass, he assumes as an actual fact that an insuperable barrier separates him from the tench, and, moreover, that it is both useless and painful to come into contact with this. He does not try to discover the nature of the obstacle, and gives up any further attempt upon his mysteriously protected prey. Man, with a more highly developed intelligence than the pike, does not accept the phenomenon of Morality with dull resignation. Since he has become conscious of a mysterious barrier erected between his volitions and his actions, he has not ceased to reflect upon this barrier, to investigate it with a timid yet irresistible desire for knowledge, and to try and discover its nature. It redounds to man's credit that he has devoted so much time and energy to investigating the character and essence of Morality. But the result of these investigations does not redound to his credit. With the exception of theology, there is no subject upon which so much has been written as upon ethics. Yet whosoever plunges into this boundless sea of literature will emerge with feelings bordering upon horror and despair. Here a free rein is given to all man's errors, to his habit of drawing false conclusions, to his faulty modes of thought. Incapacity to interpret facts, association of ideas, elusive as a will-o'-the-wisp and uncurbed by any criticism, intemperate mysticism, arrogant dogmatism, shallow self-sufficiency--all these vie with one another in the presentment of theories which either are patently foolish, arbitrary or ill-founded, or else prove to be so when impartially examined. It is hard for the few reasonable thinkers who have taken part in this great investigation to make their voices heard amid the uproar raised by the solemn, unctuous, dictatorial or pedantic tomfools. And even the former are not entirely satisfactory, because they do not distinguish clearly enough between the form and the substance, the externals and the essence of Morality, and because they do not discriminate with sufficient care between questions as to its nature, origin and aim, and its powers or sanctions--questions which must on no account be confounded.