In this phase it was animated at once by the scientific idea and by the social idea.

It was an advance both in knowledge and in moral motive.

It rested on a conception which was crude and imperfect enough, but which was still almost, like the great ecclesiastical conception itself, a conception of life as a whole.

Morality, positive law, social order, economics, the nature and limits of human knowledge, the constitution of the physical universe, had one by one disengaged themselves from theological explanations.

The final philosophical movement of the century in France, which was represented by Diderot, now tended to a new social synthesis resting on a purely positive basis.
If this movement had only added to its other contents the historic idea, its destination would have been effectually reached.