One of the most prominent was the singular conception of the nature of our first ancestors and primitive societies. Anthropology not having as yet revealed the conditions of our remoter forbears, men supposed, being influenced by the legends of the Bible, that man had issued perfect from the hands of the Creator. The first societies were models which were afterwards ruined by civilisation, but to which mankind must return. The return to the state of nature was very soon the general cry. ``The fundamental principle of all morality, of which I have treated in my writings,'' said Rousseau, ``is that man is a being naturally good, loving justice and order.'' Modern science, by determining, from the surviving remnants, the conditions of life of our first ancestors, has long ago shown the error of this doctrine. Primitive man has become an ignorant and ferocious brute, as ignorant as the modern savage of goodness, morality, and pity. Governed only by his instinctive impulses, he throws himself on his prey when hunger drives him from his cave, and falls upon his enemy the moment he is aroused by hatred. Reason, not being born, could have no hold over his instincts. The aim of civilisation, contrary to all revolutionary beliefs, has been not to return to the state of nature but to escape from it. It was precisely because the Jacobins led mankind back to the primitive condition by destroying all the social restraints without which no civilisation can exist that they transformed a political society into a barbarian horde. The ideas of these theorists concerning the nature of man were about as valuable as those of a Roman general concerning the power of omens. Yet their influence as motives of action was considerable. The Convention was always inspired by such ideas. The errors concerning our primitive ancestors were excusable enough, since before modern discoveries had shown us the real conditions of their existence these were absolutely unknown. But the absolute ignorance of human psychology displayed by the men of the Revolution is far less easy to understand. It would really seem as though the philosophers and writers of the eighteenth century must have been totally deficient in the smallest faculty of observation. They lived amidst their contemporaries without seeing them and without understanding them. Above all, they had not a suspicion of the true nature of the popular mind. The man of the people always appeared to them in the likeness of the chimerical model created by their dreams. As ignorant of psychology as of the teachings of history, they considered the plebeian man as naturally good, affectionate, grateful, and always ready to listen to reason.