Man, when regarded merely as an organism, is closely related to the
lower animals. His body is constructed on the same general plan with
theirs. More especially, he is near akin to the other members of the
class Mammalia. But we must not forget that even as an animal man is
somewhat widely separated from his humbler relations (see Fig. 7). It
is easy to say that every bone, every muscle, every convolution of his
brain, has its counterpart in the corresponding parts of an orang or a
gorilla. But, admitting this, it is also true that every one of these
parts is different, and that the aggregate of all the differences
mounts up to an enormous sum-total, more especially in relation to
habits and to capacities for action. Those remarkable homologies or
likenesses of plan which obtain in the animal kingdom are very
wonderful, and the study of them greatly enlarges our conceptions of
the unity of nature; but we must never forget that such general
agreements in plan cover the most profound differences in detail and
in adaptation to use, and that, while they indicate a common type,
this may rather point to a unity of design than to a mere accidental
unity of descent.
[Illustration: FIG. 7.
Man and his "poor relation," the gorilla. (_After Huxley._)
The head of the gorilla, with immense jaws and small
brain-case, its huge spines on the neck, its long arms, its
elongated pelvis, and its hand-like feet, with its incapacity
to assume the erect position, indicate its ordinal difference
from man, and the necessity of many intermediate forms, still
unknown, to connect the two species.]
There is a method, well known to natural science, for measuring and
indicating the divergence of man from his nearest allies. This is the
application of those principles of classification which, though of
essential importance in science, are by some modern students of nature
strangely overlooked or misunderstood. Perhaps in nothing has the
progress of ideas of evolution made a more injurious impress on the
advance of knowledge than in the manner in which it has caused many
eminent and able naturalists to diverge from all logical propriety in
their ideas of classification. Still, in so far as man is concerned,
there are some facts of this kind which are indisputable. He certainly
constitutes a distinct species, including many races, which all,
however, have common specific characters. On the other hand, no one
pretends that he is _conspecific_ with any lower animal. All
naturalists would now deride the stories, at one time current, that
gorillas and chimpanzees are degraded races of men. On the other
hand, even Haeckel admits that there is a wide gap, unfilled by any
recent or any fossil creature, between man and the highest apes.
Again, no _generic_ relationship can be claimed as between man and the
lower animals. He presents such structural differences as entitle him
to rank by himself in the genus _Homo_. Still further, the ablest
naturalists, before the rise of Darwinism, held that man was entitled
to be placed in a separate family or order from the apes. Modern
evolutionists prefer to fall back on the old arrangement of Linnæus,
and to place man and apes together in the group of Primates, which,
however, Linnæus would not have regarded as precisely of the same
value with an order as now held. In this those of them who have
sufficient ability to comprehend the facts of the case are undoubtedly
warped in judgment by the tendency of their philosophy to magnify
resemblances and to minimize differences; while the herd of feebler
men have their ideas of classification thoroughly confused by the
doctrine which they have received as a creed dictated by authority,
and to which they adhere under the influence of fear. In point of
fact, the differences between man and any other animal are so wide
that they warrant a distinction, not merely specific and generic, but
of a family and an ordinal character.
Perhaps the best way to appreciate this will be to suppose that man
has become extinct, and that in some future geological period his
fossil remains are studied by some new race of intelligent beings, and
compared with those of the lower animals his contemporaries. Let us
suppose that they have disinterred a human skull or the bones of a
human foot. From the foot they would learn that man is not an arboreal
animal, but intended to walk erect on the ground. They could infer
from this certain structures and uses of the vertebral column and of
the anterior limbs different from those found in apes, and which would
certainly induce them to conclude that they had obtained remains
indicating a new order of mammals. If they had found the foot alone,
they might doubt whether the possessor of this strange and
highly-specialized organ had been carnivorous or herbivorous, more
nearly allied to the bears or to the monkeys. Should they now find the
skull, these doubts would be solved, and they would know that the new
animal was somewhat nearer to the apes than to the bears, but still
at a very remote distance from them, and this indicated by
peculiarities of brain-case, jaws, and teeth, proving divergences in
function still wider than those apparent in the structures. They would
also plainly perceive that to link man with his nearest mammalian
allies would require the discovery of several missing links.
When we consider the psychological endowments of man, his divergence
from lower animals becomes immensely greater. In his external senses
and in the perceptions derived through them it is true he resembles
the brutes. There is also much in common with them in his appetites
and emotions, and in some of the lower manifestations of intelligence.
But he adds to this a higher reason, which causes his actions to be
differently determined from theirs; and this higher reason, or
spiritual nature, leads him to abstract ideas, to consciousness, to
notions of right and of wrong, to ideas of higher spiritual beings and
of futurity altogether unknown to lower animals. This divine reason,
in connection with special vocal contrivances, also bestows on him the
gift of speech. Nor can speech be reduced to a mere imitation of
natural sounds; for, granting that these sounds may be the raw
material of speech, yet man is enabled to apply this to the expression
of ideas in a manner altogether peculiar to himself. Scientific
precision obliges us to recognize these differences, and to admit that
they place man on an entirely different plane from the lower animals.
Perhaps the expression "a different plane" is scarcely correct, for
man can exist on many different planes--a fact which has produced some
confusion in the minds of naturalists not versed in psychological
questions, though, when rightly considered, it marks very strongly the
distinction between the man and the mere animal.
The lower animals are tied up by invariable instincts to certain lines
of action which keep all the individuals of any species on nearly the
same level, except where some little disturbance may be caused by man
in his processes of domestication. But with man it is quite different.
He is emancipated from the bond of instinct, and left free to follow
the guidance of his own will, determined by his own reason. It follows
that the habits and the actions of a man depend on what he knows and
believes, and on the deductions of his reason from these premises.
Without knowledge, culture, and training, man is more helpless than
any brute. With the noblest and highest capacities, he may devise and
follow habits of life more base than those of any mere animal. Thus
there is an almost immeasurable difference between the Godlike height
to which man can attain by the right use of his powers and the depth
to which ignorance and depravity may degrade him. It follows that the
degradation of the lower races of men is as strong a proof of the
difference between man and the lower animals as is the elevation of
the higher races. Both are characteristic of a being emancipated from
the control of instinct, knowing good and evil, free to choose, and
differing in these respects from every other creature on earth. Such
is man as we find him; and we may well ask by what process animal
instinct could ever spontaneously develop human freedom and human
reason.
But we might have evidence of such a process, however strange and
improbable it might at first sight appear. We might be able to trace
man back in history or by prehistoric remains to greater and greater
approximation to the lower animals, and might thus bridge over the
great chasm now existing between man and beast. It may be instructive,
therefore, to glance at what geology discloses as to the origin of man
and his first appearance on the earth.
In the older geological formations no remains of man or of his works
have been found. Nor do we expect to find them, for none of the
animals more nearly related to man then existed, and the condition of
the earth was probably not suited to them. Nor do we find human
remains even in the earlier Tertiary. Here also we do not expect them,
for the Mammalia of those times were all specifically distinct from
those of the modern world. It is only in the Pliocene period that we
begin to find modern species of mammals. Here, therefore, we may look
for human remains; but we do not find them as yet, and it is only at
the close of the Pliocene, or even after the succeeding Glacial
period, that we find undoubted traces of man. Let us glance at the
significance of this.
Mammalian life probably culminated or attained to its maximum in the
Miocene and the early Pliocene periods. Then there were more numerous,
larger, and better-developed quadrupeds on our continents than we now
find. For example, the elephants, the noblest of the mammals, are at
present represented by two species confined to India and parts of
Africa.[8] In the Middle Tertiary there were, in addition to the
ordinary elephants, two other genera, Mastodon and Dinotherium, and
there were many species which were distributed over the whole northern
hemisphere. The sub-Himalayan deposits of India alone have, I believe,
afforded seven species, some of them of grander dimensions than either
of those now existing. We have no trustworthy evidence as yet that man
lived at this period. If he had, he either would have required the
protection of a special Eden, or would have needed superhuman strength
and sagacity.
But the grand mammalian life of the Middle Tertiary was destined to
die out. At the close of the Pliocene came an age of refrigeration,
when arctic cold crept down over our continents far to the south, and
when most of the animals suited to temperate climates were either
frozen out or driven southward. During, or closing, this period was
also a great submergence of the continents, which must have been
equally destructive to mammalian life, and which extended over both
Eurasia and America till the summits of some of the highest hills were
under water. Attempts have been made to show that man existed before
or during the Glacial Age, but this is very unlikely, and, as I have
elsewhere argued, the evidence adduced to prove so great antiquity of
man, whether in America or Europe, has altogether broken down.[9]
At the close of the Glacial period the continents re-emerged and
became more extensive than at present. Survivors of the Pliocene
species, as well as other species not previously known, spread
themselves over this new land. It would appear that it was in this
"Post-Glacial" period that man made his appearance, and that he was
then contemporary with many large animals now extinct, and was the
possessor of wider continental areas than his descendants now enjoy.
To this age belong those human bones and implements found in the older
cave and gravel deposits of Europe, and which are referred to those
palæolithic or palæocosmic ages which preceded the dawn of history in
Europe and the arrival therein of the present European races. The
occupation of Europe, and probably of Western Asia, by these oldest
tribes of men was closed by a subsidence or submergence at the end of
that "second continental period," as it has been called by Lyell,[10]
in which they lived. When the land was restored to its present
condition, they were replaced by the ancestors of the present European
races.
It may be well here to tabulate that later portion of the earth's
geological history in which man appeared, more especially as it is
sometimes arranged in a manner not suited to convey a correct
impression of the actual succession. It will be seen by the general
table given in the last lecture that the latest of the Tertiary ages
is that known as the Pleistocene or Post-Pliocene, and this, with the
succeeding modern period, may be best arranged as follows: