The Dawning of Consciousness.
Here we arrive at one of the most wonderful moments in the history of
creation,--the moment of the first faint dawning of consciousness, the
foreshadowing of the true life of the soul. Whence came the soul we no
more know than we know whence came the universe. The primal origin of
consciousness is hidden in the depths of the bygone eternity. That it
cannot possibly be the product of any cunning arrangement of material
particles is demonstrated beyond peradventure by what we now know of the
correlation of physical forces.[4] The Platonic view of the soul, as a
spiritual substance, an effluence from Godhood, which under certain
conditions becomes incarnated in perishable forms of matter, is
doubtless the view most consonant with the present state of our
knowledge. Yet while we know not the primal origin of the soul, we have
learned something with regard to the conditions under which it has
become incarnated in material forms. Modern psychology has something to
say about the dawning of conscious life in the animal world. Reflex
action is unaccompanied by consciousness. The nervous actions which
regulate the movements of the viscera go on without our knowledge; we
learn of their existence only by study, as we learn of facts in outward
nature. If you tickle the foot of a person asleep, and the foot is
withdrawn by simple reflex action, the sleeper is unconscious alike of
the irritation and of the movement, even as the decapitated frog is
unconscious when a drop of nitric acid falls on his back and he lifts up
a leg and rubs the place. In like manner the reflex movements which make
up the life of the lowest animals are doubtless quite unconscious, even
when in their general character they simulate conscious actions, as they
often do. In the case of such creatures, the famous hypothesis of
Descartes, that animals are automata, is doubtless mainly correct. In
the case of instincts also, where the instinctive actions are completely
organized before birth, and are repeated without variation during the
whole lifetime of the individual, there is probably little if any
consciousness. It is an essential prerequisite of consciousness that
there should be a period of delay or tension between the receipt of an
impression and the determination of the consequent movement. Diminish
this period of delay and you diminish the vividness of consciousness. A
familiar example will make this clear. When you are learning to play a
new piece of music on the piano, especially if you do not read music
rapidly, you are intensely conscious of each group of notes on the page,
and of each group of keys that you strike, and of the relations of the
one to the other. But when you have learned the piece by heart, you
think nothing of either notes or keys, but play automatically while your
attention is concentrated upon the artistic character of the music. If
somebody thoughtlessly interrupts you with a question about Egyptian
politics, you go on playing while you answer him politely. That is,
where you had at first to make a conscious act of volition for each
movement, the whole group of movements has now become automatic, and
volition is only concerned in setting the process going. As the delay
involved in the perception and the movement disappears, so does the
consciousness of the perception and the movement tend to disappear.
Consciousness implies perpetual discrimination, or the recognition of
likenesses and differences, and this is impossible unless impressions
persist long enough to be compared with one another. The physical organs
in connection with whose activity consciousness is manifested are the
upper and outer parts of the brain,--the cerebrum and cerebellum. These
organs never receive impressions directly from the outside world, but
only from lower nerve-centres, such as the spinal cord, the medulla, the
optic lobes, and other special centres of sensation. The impressions
received by the cerebrum and cerebellum are waves of molecular
disturbance sent up along centripetal nerves from the lower centres, and
presently drafted off along centrifugal nerves back to the lower
centres, thus causing the myriad movements which make up our active
life. Now there is no consciousness except when molecular disturbance is
generated in the cerebrum and cerebellum faster than it can be drafted
off to the lower centres.[5] It is the surplus of molecular disturbance
remaining in the cerebrum and cerebellum, and reflected back and forth
among the cells and fibres of which these highest centres are composed,
that affords the physical condition for the manifestation of
consciousness. Memory, emotion, reason, and volition begin with this
retention of a surplus of molecular motion in the highest centres. As we
survey the vertebrate sub-kingdom of animals, we find that as this
surplus increases, the surface of the highest centres increases in area.
In the lowest vertebrate animal, the amphioxus, the cerebrum and
cerebellum do not exist at all. In fishes we begin to find them, but
they are much smaller than the optic lobes. In such a highly organized
fish as the halibut, which weighs about as much as an average-sized man,
the cerebrum is smaller than a melon-seed. Continuing to grow by adding
concentric layers at the surface, the cerebrum and cerebellum become
much larger in birds and lower mammals, gradually covering up the optic
lobes. As we pass to higher mammalian forms, the growth of the cerebrum
becomes most conspicuous, until it extends backwards so far as to cover
up the cerebellum, whose functions are limited to the conscious
adjustment of muscular movements. In the higher apes the cerebrum begins
to extend itself forwards, and this goes on in the human race. The
cranial capacity of the European exceeds that of the Australian by forty
cubic inches, or nearly four times as much as that by which the
Australian exceeds the gorilla; and the expansion is almost entirely in
the upper and anterior portions. But the increase of the cerebral
surface is shown not only in the general size of the organ, but to a
still greater extent in the irregular creasing and furrowing of the
surface. This creasing and furrowing begins to occur in the higher
mammals, and in civilized man it is carried to an astonishing extent.
The amount of intelligence is correlated with the number, the depth, and
the irregularity of the furrows. A cat's brain has a few symmetrical
creases. In an ape the creases are deepened into slight furrows, and
they run irregularly, somewhat like the lines in the palm of your hand.
With age and experience the furrows grow deeper and more sinuous, and
new ones appear; and in man these phenomena come to have great
significance. The cerebral surface of a human infant is like that of an
ape. In an adult savage, or in a European peasant, 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.