means. For man is enabled through his mental faculties to keep with an
unchanged body in harmony with the changing universe. He has great
power of adapting his habits to new conditions of life. He invents
weapons, tools, and various stratagems to procure food and to defend
himself. When he migrates into a colder climate he uses clothes, builds
sheds, and makes fires; and by the aid of fire cooks food otherwise
indigestible. He aids his fellow-men in many ways, and anticipates
future events. Even at a remote period he practised some division of
labour.
The lower animals, on the other hand, must have their bodily structure
modified in order to survive under greatly changed conditions. They
must be rendered stronger, or acquire more effective teeth or claws,
for defence against new enemies; or they must be reduced in size, so as
to escape detection and danger. When they migrate into a colder
climate, they must become clothed with thicker fur, or have their
constitutions altered. If they fail to be thus modified, they will
cease to exist.
The case, however, is widely different, as Mr. Wallace has with justice
insisted, in relation to the intellectual and moral faculties of man.
These faculties are variable; and we have every reason to believe that
the variations tend to be inherited. Therefore, if they were formerly
of high importance to primeval man and to his ape-like progenitors,
they would have been perfected or advanced through natural selection.
Of the high importance of the intellectual faculties there can be no
doubt, for man mainly owes to them his predominant position in the
world. We can see, that in the rudest state of society, the individuals
who were the most sagacious, who invented and used the best weapons or
traps, and who were best able to defend themselves, would rear the
greatest number of offspring. The tribes, which included the largest
number of men thus endowed, would increase in number and supplant other
tribes. Numbers depend primarily on the means of subsistence, and this
depends partly on the physical nature of the country, but in a much
higher degree on the arts which are there practised. As a tribe
increases and is victorious, it is often still further increased by the
absorption of other tribes. (2. After a time the members or tribes
which are absorbed into another tribe assume, as Sir Henry Maine
remarks ( Ancient Law, 1861, p. 131), that they are the co-descendants
of the same ancestors.) The stature and strength of the men of a tribe
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