a large increase in numbers is possible without
much separation; civilization gains the advantage of exemption from
tribal war, even when the community as a whole is carrying on warfare
beyond its borders. Thus, where the resistance of nature to the close
association of men is slightest, the counterforce of warfare is likely
at first to be least felt; and in the rich plains where civilization
first begins, it may rise to a great height while scattered tribes are
yet barbarous. And thus, when small, separated communities exist in a
state of chronic warfare which forbids advance, the first step to their
civilization is the advent of some conquering tribe or nation that
unites these smaller communities into a larger one, in which internal
peace is preserved. Where this power of peaceable association is broken
up, either by external assaults or internal dissensions, the advance
ceases and retrogression begins.

But it is not conquest alone that has operated to promote association,
and, by liberating mental power from the necessities of warfare, to
promote civilization. If the diversities of climate, soil, and
configuration of the earth's surface operate at first to separate
mankind, they also operate to encourage exchange. And commerce, which is
in itself a form of association or co-operation, operates to promote
civilization, not only directly, but by building up interests which are
opposed to warfare, and dispelling the ignorance which is the fertile
mother of prejudices and animosities.

And so of religion. Though the forms it has assumed and the animosities
it has aroused have often sundered men and produced warfare, yet it has
at other times been the means of promoting association. A common worship
has often, as among the Greeks, mitigated war and furnished the basis of
union, while it is from the triumph of Christianity over the barbarians
of Europe that modern civilization springs. Had not the Christian Church
existed when the Roman Empire went to pieces, Europe, destitute of any
bond of association, might have fallen to a condition not much above
that of the North American Indians or only received civilization with an
Asiatic impress from the conquering scimiters of the invading hordes
which had been welded into a mighty power by a religion which, springing
up in the deserts of Arabia, had united tribes separated from time
immemorial, and, thence issuing, brought into the association of a
common faith a great part