HOW AN IDEA ENTERS THE MIND
When an impression is made on a sense organ, the sensation derived from
it is telegraphed up the connecting nerve fibre to the brain, and there
translated, by a process of which we know nothing, from a sensation to
a thought.
We believe that the mind learns by experience to associate certain
kinds of sensation with certain objects or conditions in the
environment, and when it feels these particular sensations, deduces
that certain objects are present, and forms mental images, or thought
models, intended to represent these objects.
The truth of our percepts is determined by the closeness with which
our thought model corresponds to its original. An exact copy is a true
concept, an imperfect copy an inaccurate concept.
We “recognise” an object by a process of classification, noting
its likeness or unlikeness to other objects already known. When
an unfamiliar object attracts our attention, we put it through a
process of comparison until we find to which compartment in our
concept-pictures it should be assigned, and if we cannot find a perfect
match, we put it in the most suitable compartment we can discover,
and then partition off a little subclass for it, thus admitting its
identity in essentials, but its difference in details from the other
occupants of that compartment.
For example, supposing we were to land on an island and an object on
the shore attracted our attention, we should try to see what class of
things of which we already had experience it most closely resembled.
We should observe its movements, and assign it to the class of living
creatures; see its four limbs and hair, and conclude it was an animal.
Note its upright attitude, clothes, and weapons, and recognise these as
characteristic of humanity; but perceiving that its skin differed in
colour from that of any human being we had ever seen before, we should
partition off a fresh subdivision in the department of our mind in
which our ideas connected with humanity were stored, place it there,
and probably give it a distinguishing name by means of which we could
indicate it to other human beings.
Supposing, however, we presently come across another object of the same
nature, we should not have to make a fresh subdivision for it, but
would classify it with the previously examined specimen, and thus we
should feel this time that we “knew what it was.” In fact, the process
of “knowing” is a process of classification, and we feel that we “know”
a thing when we have assigned it to a satisfactory pigeon-hole among
our concepts.