Belief in liberty has been born from the diversity of human aptitude, from man's power to reach the necessary termination of his activity by different routes, or to dodge this termination and suicide in himself the species whose future he bears. It, this liberty, is an illusion difficult not to have, an idea which one must shed if one wants to think in a manner not wholly irrational, but it is recompensingly certain that the multiplicity of possible activities is almost an equivalent of this liberty. Doubtless the strongest motive always wins, but today's stronger is tomorrow's weaker, hence a variety of human gaits feigning liberty, and practically resulting therein. Free will is only the faculty of being guided successively by a great number of different motives. When choice is possible, liberty begins, even though the chosen act is rigorously determined and when there is no possibility of avoiding it. Animals have a smaller liberty, restricted in proportion as their aptitudes are more limited; but when life begins liberty begins. The distinction, from this view-point, between man and animal is quantitative, and not qualitative. One must not be gulled by the scholastic distinction between instinct and intelligence; man is as full of instincts as the insect most visibly instinctive; he obeys them by methods more diverse, that is all there is to it. If it is clear that man is an animal, it is also clear that he is a very complex one. One finds in him most of the aptitudes which are distributed one by one among beasts. There is hardly one of his habits, of his virtues, of his vices (to use the conventional terms) which can not be found either in an insect, a bird or a mammifer: monogamy, adultery, the "consequences"; polygamy, polyandry, lasciviousness, laziness, activity, cruelty, courage, devotion, any of these are common to animals, but each as the quality of an whole species. In the state of differentiation to which superior and cultivated human species have attained, each individual forms surely a separate variety determined by what is called, abstractly, "the character." This individual differentiation, very marked in mankind, is less marked in other animal species. Yet we note quite distinct characters in dogs, in horses and even in birds of the same race. It is quite probable that all bees have not the same character, since, for example, they are not all equally prompt to use their stings in analogous circumstances. Even there the difference between man and his brothers-in-life and in sensibility is but a difference of degree.