confirmed by his observations of his fellow creatures, and perfected little by little by his experience of social life."
We thus see that the thinkers of the eighteenth century did not change their method when they passed from the stars and physical bodies to the world of chemical reactions, or from the physical and chemical world to the life of plants and animals, to Man and to the development of economical and political forms of human society, and finally, to the evolution of the moral sense, the religions, and so on.
The method remained the same. To all branches of science they applied the inductive method. And neither in the study of religions, nor in the analysis of the moral sense and in that of thought altogether, did they find a single case in which their method failed, or in which another method was necessary. Nowhere did they find themselves compelled to have recourse to metaphysical conceptions ("immortal soul," "imperative and categorical laws" inspired by a superior being, etc.), or to any sort of purely dialectic method. And consequently they endeavoured to explain the whole of the universe and all its phenomena in the same way, as naturalists.
During those memorable years of awakening of scientific thought, the Encyclopaedists built their monumental "Encyclopaedia." Laplace published his "System of the Universe," and Holbach his "System of Nature." Lavoisier asserted the indestructibility of matter, and consequently of energy and movement. Lomonosoff, inspired by Bayle, sketched already at that time his mechanical theory of heat; Lamarck explained the origin of the infinitely varied species of plants and animals by adaptation to their divers surroundings; Diderot gave an explanation of moral feeling, of moral customs, of primitive and religious institutions, without having recourse to inspiration from above; Rousseau endeavoured to explain the birth of political institutions following upon a social contract—that is to say, by an act of human will. In short, there was not a sphere which they did not study by means of facts, by the same method of scientific induction and deduction verified by facts.
Of course, more than one error was committed in that great and bold attempt. There, where knowledge was wanting, erroneous and unconfirmed suppositions were sometimes made. But a new method had been applied to whole of human knowledge, and, thanks to this new method, the errors themselves were easily recognised and corrected later on. By this means the nineteenth
