on of
Plato. It takes into consideration only historical times and it has, as
an instrument of research, only the fantastic logic of the school-men.
The generations which preceded us, have all been imbued with this notion
of the absoluteness of natural laws, the conflicting laws of a dual
universe of matter and spirit. Modern science, on the contrary, starts
from the magnificent synthetic conception of monism, that is to say, of
a single substance underlying all phenomena--matter and force being
recognized as inseparable and indestructible, continuously evolving in a
succession of forms--forms relative to their respective times and
places. It has radically changed the direction of modern thought and
directed it toward the grand idea of universal evolution.[47]

Ethics, law and politics are mere superstructures, effects of the
economic structure; they vary with its variations, from one parallel (of
latitude or longitude) to another, and from one century to another.

This is the great discovery which the genius of Karl Marx has expounded
in his _Critique de l'economie politique_. I will examine further on the
question as to what this sole source or basis of the varying economic
conditions is, but the important point now is to emphasize their
constant variability, from the pre-historic ages down to historical
times and to the different periods of the latter.

Moral codes, religious creeds, juridical institutions both civil and
criminal, political organization:--all are constantly undergoing
transformation and all are relative to their respective historical and
material environments.

To slay one's parents is the greatest of crimes in Europe and America;
it is, on the contrary, a duty enjoined by religion in the island of
Sumatra; in the same way, cannibalism is a permitted usage in Central
Africa, and such it also was in Europe and America in pre-historic ages.

The family is, at first (as among animals), only a sort of sexual
communism; then polyandry and the matriarchal system were established
where the supply of food was scanty and permitted only a very limited
increase of population; we find polygamy and the patriarchal system
appearing whenever and wherever the tyranny of this fundamental economic
cause of polyandry ceases to be felt; with the advent of historical
times appears the monogamic form of the family the best and the most
advanced form, although it is still requisite for it to be freed from
the rigid co