the internal domain of conscience, and the external domain of observation.
The man of our time finds in the depth of his consciousness the idea of good and evil, and the ineffaceable feeling of duty that is the categorical imperative of Kant. Duty is further conceived as toward himself and toward other men—that is, he comprehends the solidarity of his relations. These are fundamental facts of consciousness, independent of all theological or metaphysical hypothesis. The ideas acquired from the exterior source of our consciousness—that is, from history and the natural sciences—present morality under a different light, in that they show the instinctive origin and the evolution of it. The human species, in fact, only represents a particular case among the multitude of animal species that live in society. With these we witness, according to the degree of perfection they manifest, the appearance of the first elements of morals. The family, offspring of the instincts that preside over the preservation of the species, exists, temporarily at least, among birds and mammals, not to go lower. It coexists with the feeling of maternal love, and in certain cases of paternal love, raised to the highest degree.
With the feeling of the family we meet also, among the social species, that of solidarity and the devotion of the individual to the collective whole, rising sometimes to the sacrifice of his life. The study of the still savage human races has shown how near their special morality lies to that of the social animal species, if it is not even inferior to that of some of them. There are, in this respect, great differences in the social instincts, among men as well as among animals. But the existence of a general basis common to both is demonstrated by observation.
The social instincts, and the feelings and duties derived from them, are not, then, peculiar to the human species, and due to some strange and divine revelation, but are inherent in the cerebral and physiological constitution of man—a constitution similar to that of the animals, but of a superior order, and having become more so during the course of centuries by the effects of the conquests of our intelligence. The hereditary perfection of these instincts is the real basis of morals, and the point of departure for the organization of civilized societies.
As men advanced in civilization, their positive knowledge, continually increasing, demonstrated the social utility of certain duties and certain moral laws, which were rendered obligatory by the chiefs of the states—priests and legislators. But these laws, deduced from scientific notions, were associated and in a manner amalgamated with the arbitrary prescriptions of the theocracy, and proclaimed according to mystic formulas, from which no mind was then free.