ce the accomplishment in England of the great industrial
revolution at the end of the eighteenth century, and since the great
social upheaval took place in France. These things, _mutatis mutandis_,
have subsequently been reproduced, in various combinations and in milder
forms, throughout the whole civilized world. And what else is our
thought at bottom if not the conscious and systematic complement of
experience, and what is this last if not the reflection and the mental
elaboration of the things and the processes which arise and unfold
either outside our volition, or through the work of our activity; and
what is genius but the individualized, derived and acute form of
thought, which arises through the suggestion of experience, in many men
of the same epoch, but which remains in most of them fragmentary,
incomplete, uncertain, wavering and partial?

Ideas do not fall from heaven; and what is more, like the other products
of human activity, they are formed in given circumstances, in the
precise fullness of time, through the action of definite needs, thanks
to the repeated attempts at their satisfaction, and by the discovery of
such and such other means of proof which are, as it were, the
instruments of their production and their elaboration. Even ideas
involve a basis of social conditions; they have their technique; thought
also is a form of work. To rob the one and the other, ideas and thought,
of the conditions and environment of their birth and their development,
is to disfigure their nature and their meaning.

To show how the materialistic conception of history arises precisely in
given conditions, not as a personal and tentative opinion of two
writers, but as the new conquest of thought by the inevitable suggestion
of a new world which is in process of birth, that is to say the
proletarian revolution, that was the object of my first essay, "In
Memory of the Communist Manifesto." That is, to repeat, a new historic
situation found its complement in its appropriate mental instrument.

To imagine now that this intellectual production might have been
realized at any time and at any place, would be to take absurdity for
the ruling principle in research. To transport ideas arbitrarily from
the basis and the historic conditions in which they arise to any other
basis whatever, is like taking the irrational for the basis of
reasoning. Why should one not fancy equally that the ancient city, in
which arose Greek art and sci