It is hardly necessary to say that in this Condorcet was mistaken. If the "philosophers" in this branch of their investigations arrived at conclusions of incontestable though very relative value, they unconsciously owed this to the fact that they constantly abandoned their abstract standpoint of human nature in general, and took up that of a more or less idealised nature of a man of the Third Estate. This man "felt" and "reasoned," after a fashion very clearly defined by his social environment. It was his "nature" to believe firmly in bourgeois property, representative government, freedom of trade (_laissez-faire, laissez passer!_ the "nature" of this man was always crying out), and so on. In reality, the French philosophers always kept in view the economic and political requirements of the Third Estate; this was their real criterion. But they applied it unconsciously, and only after much wandering in the field of abstraction did they arrive at it. Their conscious method always reduced itself to abstract considerations of "human nature," and of the social and political institutions that best harmonise with this nature. Their method was also that of the Socialists. A man of the 18th century, Morelly, "to anticipate a mass of empty objections that would be endless," lays down as an incontrovertible principle "that in morals nature is one, constant, invariable ... that its laws never change;" and that "everything that may be advanced as to the variety in the morals of savage and civilised peoples, by no means proves that nature varies;" that at the outside it only shows "that from certain accidental causes which are foreign to it, some nations have fallen away from the laws of nature; others have remained submissive to them, in some respects from mere habit; finally, others are subjected to them by certain reasoned-out laws that are not always in contradiction with nature;" in a word, "man may abandon the True, but the True can never be annihilated!"[1] Fourier relies upon the analysis of the human passions; Robert Owen starts from certain considerations on the formation of human character; Saint Simon, despite his deep comprehension of the historical evolution of humanity, constantly returns to "human nature" in order to explain the laws of this evolution; the Saint-Simonians declared their philosophy was "based upon a new conception of human nature." The Socialists of the various schools may quarrel as to the cause of their different conceptions of human nature; all, without a single exception, are convinced that social science has not and cannot have, any other basis than an adequate concept of this nature. In this they in no wise differ from the Materialists of the 18th century. Human nature is the one criterion they invariably apply in their criticism of existing society, and in their search after a social organisation as it should be, after a "perfect" legislation.