de
almost no progress. There is nothing intrinsically progressive in his
nature. Let a group of men be isolated at any stage of human evolution,
and placed in an unchanging environment, and they will remain stationary
for an indefinite period. When Europeans began to traverse the globe in
the last few centuries, they picked up here and there little groups of
men who had, in their isolation, remained just where their fathers had
been when they quitted the main road of advance in the earlier stages
of the Old Stone Age. The evolution of man is guided by the same laws
as the evolution of any other species. Thus we can understand the long
period of stagnation, or of incalculably slow advance. Thus, too, we can
understand why, at length, the pace of man toward his unconscious goal
is quickened. He is an inhabitant of the northern hemisphere, and
the northern hemisphere is shaken by the last of the great geological
revolutions. From its first stress emerges the primeval savage of the
early part of the Old Stone Age, still bearing the deep imprint of his
origin, surpassing his fellow-animals only in the use of crude stone
implements. Then the stress of conditions relaxes--the great ice-sheet
disappears--and again during a vast period he makes very little
progress. The stress returns. The genial country is stripped and
impoverished, and the reindeer and mammoth spread to the south of
Europe. But once more the adversity has its use, and man, stimulated
in his hunt for food, invigorated by the cold, driven into social life,
advances to the culmination of the Old Stone Age.

We are still very far from civilisation, but the few tens of thousands
of years that separate Magdalenian man from it will be traversed with
relative speed--though, we should always remember, with a speed far
less than the pace at which man is advancing to-day. A new principle now
enters into play: a specifically human law of evolution is formulated.
It has no element of mysticism, and is merely an expression of the fact
that the previous general agencies of development have created in man
an intelligence of a higher grade than that of any other animal. In his
larger and more plastic brain the impressions received from the outer
world are blended in ideas, and in his articulate speech he has a unique
means of entering the idea-world of his fellows. The new principle
of evolution, which arises from this superiority, is that man's chief
stimulus to advance will