The Central And Peripheral Nervous Systems In Action

I am passing the open door of a bake-shop, and a pervading odor fills

the air. I think "hot rolls," because my organ of smell--the nose--has

received a stimulus which it transmits along my olfactory nerves to the

brain; and there the odor is given a name--"hot rolls." The recognition

of the stimulus as an odor and of that odor as "hot rolls" is

consciousness in the form of thinking. But the odor arouses desire to

unger; and this is consciousness in the form of feeling. The

something which makes me walk into the shop and buy the rolls is

consciousness in the form of willing. The sensory appeal from the

outside world gained admission through the sense of smell; this

transmitted the message, and consciousness recognized the stimulus,

which immediately appealed to my hunger and incited action to satisfy

that hunger.

The ear of the operator in the telegraph office, again, might illustrate

consciousness. It must be able to interpret mere clickings into terms of

sense. To the operator the sounds say words, and the words are the

expression of the object at the other end of the wire. The brain is the

receiving operator for all the senses, which bring their messages in

code, and which it interprets first as sound, vision, taste, touch,

feel, smell, temperature; then more accurately as words, trees, sweet,

soft, round, acrid, hot.

The mind can know nothing except as the stimulus is transmitted by

sense-channels over the nerves of sense, and received by a conscious

brain. A baby born without sight, hearing, taste, smell, or touch would

remain a mere bit of clay. He could have no awareness. But so long as

any one sense channel remains open the mind may acquire some knowledge.

Suppose I am paralyzed, blind, and deaf, and you put a tennis-ball into

my hand. I cannot tell you what it is, not even what it is like. It

means nothing whatever to me, for the sense channels of touch, sight,

and hearing, through which alone it could be impressed upon my brain,

are gone. Suppose I am blind and deaf, but have my sense of touch

intact; that I never saw or touched or heard of a tennis-ball before,

but I know "apple" and "orange." I can judge that the object is round,

that it is about the size of a small orange or apple. It is very light,

and has a feel of cloth. I know it to be something new in my experience.

You tell me in the language of touch that it is "tennis-ball"; and

thereafter I recognize it by its combination of size, feel, and weight,

and can soon name it as quickly as you, who see it.

Suppose I am blind and my hands are paralyzed, but I have my hearing.

You tell me this is a tennis-ball, and if I have known "tennis-ball" in

the past, I can describe it to you. It has been impressed upon my brain

through my sense of hearing; and memory immediately supplies the

qualities that go with "tennis-ball."

But if none of the senses has ever developed, my brain can receive no

impression whatever; it cannot have even the stimulus of memory. Hence

conscious mind cannot be, except as some sense-channel or channels have

been opened to carry thought material to the brain. So far as we know

today, in this world, mind is absolutely dependent upon the sense organs

and the brain--upon matter--for existence.