Man stands apart from animals in his power of building up general ideas
and of using these in the guidance of his behaviour and the control of
his conduct. This is essentially wrapped up with his development of
language as an instrument of thought. Some animals have words, but man
has language (Logos). Some animals show evidence of _perceptual_
inference, but man often gets beyond this to _conceptual_ inference
(Reason). Many animals are affectionate and brave, self-forgetful and
industrious, but man "thinks the ought," definitely guiding his conduct
in the light of ideals, which in turn are wrapped up with the fact that
he is "a social person."
Besides his big brain, which may be three times as heavy as that of a
gorilla, man has various physical peculiarities. He walks erect, he
plants the sole of his foot flat on the ground, he has a chin and a good
heel, a big forehead and a non-protrusive face, a relatively uniform set
of teeth without conspicuous canines, and a relatively naked body.
[Illustration: DIAGRAM SHOWING SEVEN STAGES IN THE EVOLUTION OF THE
FORE-LIMBS AND HIND-LIMBS OF THE ANCESTORS OF THE MODERN HORSE,
BEGINNING WITH THE EARLIEST KNOWN PREDECESSORS OF THE HORSE AND
CULMINATING WITH THE HORSE OF TO-DAY
(_After Marsh and Lull._)
1 and 1A, fore-limb and hind-limb of Eohippus; 2 and 2A, Orohippus; 3
and 3A, Mesohippus; 4 and 4A, Hypohippus; 5 and 5A, Merychippus; 6 and
6A, Hipparion; 7 and 7A, the modern horse. Note how the toes shorten and
disappear.]
[Illustration: A. Fore-limb of Monkey B. Fore-limb of Whale
WHAT IS MEANT BY HOMOLOGY? ESSENTIAL SIMILARITY OF ARCHITECTURE, THOUGH
THE APPEARANCES MAY BE VERY DIFFERENT
This is seen in comparing these two fore-limbs, A, of Monkey, B, of
Whale. They are as different as possible, yet they show the same bones,
e.g. SC, the scapula or shoulder-blade; H, the humerus or upper arm; R
and U, the radius and ulna of the fore-arm; CA, the wrist; MC, the palm;
and then the fingers.]
But in spite of man's undeniable apartness, there is no doubt as to his
solidarity with the rest of creation. There is an "all-pervading
similitude of structure," between man and the Anthropoid Apes, though it
is certain that it is not from any living form that he took his origin.
None of the anatomical distinctions, except the heavy brain, could be
called momentous. Man's body is a veritable museum of relics (vestigial
structures) inherited from pre-human ancestors. In his everyday bodily
life and in some of its disturbances, man's pedigree is often revealed.
Even his facial expression, as Darwin showed, is not always human. Some
fossil remains bring modern man nearer the anthropoid type.
It is difficult not to admit the ring of truth in the closing words of
Darwin's _Descent of Man_:
"We must, however, acknowledge, as it seems to me, that man, with
all his noble qualities, with sympathy which feels for the most
debased, with benevolence which extends not only to other men but to
the humblest living creature, with his God-like intellect which has
penetrated into the movements and constitution of the solar
system--with all these exalted powers--man still bears in his bodily
frame the indelible stamp of his lowly origin."