Caesar and Tacitus give a great deal
of information about the barbarous conditions from which civilization
evolved.

But much more is known that materially amplifies the account of human
progress based upon documents alone. The student of existing human races
early learns that social structure is a very varied thing. The natives of
northern Africa now live in a semi-civilized state which is very like that
of medieval England. In Siberia and the American Southwest are tribes that
correspond socially with the barbarians of Europe described by Greek and
Roman writers. The American Indians discovered by the earliest colonists,
the Polynesians of a century ago, and the Fuegians of recent decades
provide counterparts of the ancient stone-wielding people who were the
savage ancestors of European barbarians. Hence the comparative study and
classification of modern races establishes a scale of social grades which
corresponds with the order of their historic succession, just as in a
larger way the complete series of comparative anatomy from _Amoeba_ to
man displays the order of evolution from unicellular beginnings to the
present culminating types. Savagery, barbarism, and civilization are the
three major terms of this social scale, but by no means are they
discontinuous, for many intermediate forms of organization occur which are
transitional from one major type to a higher one.

In human social evolution the starting point is not so simple as the
solitary unit from which insect societies evolved,--that is, an organism
which lives alone and is associated with another of its species only at
the time of mating. The lowest human beings now existing have some form of
family organization, traceable to the more or less continuous unions
formed among certain of the apes and even among many lower animals, and
not a characteristic that belongs to mankind alone. The savage and his
mate constitute the social unit out of which all else is built up; the man
and the woman must perform all of the vital tasks demanded by nature.
Fruits and vegetables must be secured from the wild forest or by
cultivation; the flesh of game animals or of a human victim is no less
essential for food. The savage is his own weapon maker and warrior; he
himself builds the rude shelter for his family and fashions the canoe if
such is required. He is also his own judge, recognizing no control save
the dictates of his wishes and needs, for he does not consciously reali