The Destiny of Man | Page 9

the furrowing is
somewhat marked and complicated. In the brain of a great scholar, the
furrows are very deep and crooked, and hundreds of creases appear
which are not found at all in the brains of ordinary men. In other words,
the cerebral surface of such a man, the seat of conscious mental life,
has become enormously enlarged in area; and we must further observe
that it goes on enlarging in some cases into extreme old age.[6]
Putting all these facts together, it becomes plain that in the lowest
animals, whose lives consist of sundry reflex actions monotonously
repeated from generation to generation, there can be nothing, or next to
nothing, of what we know as consciousness. It is only when the life
becomes more complicated and various, so that reflex action can no

longer determine all its movements and the higher nerve-centres begin
to be evolved, that the dawning of consciousness is reached. But with
the growth of the higher centres the capacities of action become so
various and indeterminate that definite direction is not given to them
until after birth. The creature begins life as an infant, with its partially
developed cerebrum representing capabilities which it is left for its
individual experience to bring forth and modify.

VI.
Lengthening of Infancy, and Concomitant Increase of Brain-Surface.
The first appearance of infancy in the animal world thus heralded the
new era which was to be crowned by the development of Man. With
the beginnings of infancy there came the first dawning of a conscious
life similar in nature to the conscious life of human beings, and there
came, moreover, on the part of parents, the beginning of feelings and
actions not purely self-regarding. But still more, the period of infancy
was a period of plasticity. The career of each individual being no longer
wholly predetermined by the careers of its ancestors, it began to
become teachable. Individuality of character also became possible at
the same time, and for the same reason. All birds and mammals which
take care of their young are teachable, though in very various degrees,
and all in like manner show individual peculiarities of disposition,
though in most cases these are slight and inconspicuous. In dogs,
horses, and apes there is marked teachableness, and there are also
marked differences in individual character.
But in the non-human animal world all these phenomena are but
slightly developed. They are but the dim adumbrations of what was by
and by to bloom forth in the human race. They can scarcely be said to
have served as a prophecy of the revolution that was to come. One
generation of dumb beasts is after all very like another, and from
studying the careers of the mastodon, the hipparion, the sabre-toothed
lion, or even the dryopithecus, an observer in the Miocene age could
never have foreseen the possibility of a creature endowed with such a

boundless capacity of progress as the modern Man. Nevertheless,
however dimly suggestive was this group of phenomena, it contained
the germ of all that is preëminent in humanity. In the direct line of our
ancestry it only needed that the period of infancy should be sufficiently
prolonged, in order that a creature should at length appear, endowed
with the teachableness, the individuality, and the capacity for progress
which are the peculiar prerogatives of fully-developed Man.[7] In this
direct line the manlike apes of Africa and the Indian Archipelago have
advanced far beyond the mammalian world in general. Along with a
cerebral surface, and an accompanying intelligence, far greater than
that of other mammals, these tailless apes begin life as helpless babies,
and are unable to walk, to feed themselves, or to grasp objects with
precision until they are two or three months old. These apes have thus
advanced a little way upon the peculiar road which our half-human
forefathers began to travel as soon as psychical variations came to be of
more use to the species than variations in bodily structure. The gulf by
which the lowest known man is separated from the highest known ape
consists in the great increase of his cerebral surface, with the
accompanying intelligence, and in the very long duration of his infancy.
These two things have gone hand in hand. The increase of cerebral
surface, due to the working of natural selection in this direction alone,
has entailed a vast increase in the amount of cerebral organization that
must be left to be completed after birth, and thus has prolonged the
period of infancy. And conversely the prolonging of the plastic period
of infancy, entailing a vast increase in teachableness and versatility, has
contributed to the further enlargement of the cerebral surface. The
mutual reaction of these two groups of facts must have gone on for an
enormous length of time since