Our doctrine assumes the broad, conscious and continuous development of modern technique, and with it that society which produces commodities in the antagonisms of competition, that society which as a first condition and an indispensable means for its own perpetuation presupposes capitalist accumulation in the form of private property; that society which continually produces and reproduces proletarians, and which if it is to perpetuate itself, must incessantly revolutionize its tools, and with them the State and its legal gearings. This society, which, by the very laws of its movement, has laid bare its own anatomy, produces by its reaction the materialistic conception. Even as it has produced in socialism its positive negation, so it has engendered in the new historic doctrine its ideal negation. If history is the product, not arbitrary, but necessary and normal, of men in so far as they are developing, and if they are developing in so far as they are making social experiments, and if they are experimenting in so far as they are making improvements in their labor, which accumulate and preserve products and results, the phase of development in which we live cannot be the last and final phase, and the contrasts which are intimately bound to it and inherent in it are the productive forces of new conditions. And this is how the period of the great economic and political revolutions of these last two centuries has ripened in the mind these two concepts: the immanence and constancy of the _processus_ in historic facts, and the materialist doctrine, which is at bottom the objective theory of social revolutions. It is beyond doubt that to reascend through the centuries and reconstruct in our thought the development of social ideas to the extent that we find their documents in writers, is something always very instructive, and serving especially to add to our critical knowledge of our concepts as of our ways of thinking. Such a return of the mind over its historic premises, when it does not lead us astray into the empiricism of a boundless erudition, and does not lead us to set up hastily vain analogies, serves without any doubt to give suppleness and a persuasive force to the forms of our scientific activity. In the sum of our science we find again, in fact and through the approximative continuity of tradition, the excellence of all that has been found, conceived and proved, not only in modern times but even in ancient Greece, where first begins precisely and in a definite fashion for the human race the orderly development of conscious, reflective and methodical thought. It would be impossible to take a single step in scientific research without employing means long ago found and tried, such for example as logic and mathematics. To think otherwise would be to assume that each generation must begin over again all the work done since the childhood of humanity.