imagine quite vividly picking up some object and throwing it, or kicking
something; yet we don't actually do so. On the other hand, we feel so "near"
to actually doing so. Probably the faucet catches the nerve impulses "at the
last moment".
Here is another way in which visualization points out the distinction
between accessible and inaccessible knowledge. Consider how you vi-
sualized the scene of the car skidding on the mountain road. Undoubtedly
you imagined the mountain as being much larger than the car. Now did
this happen because sometime long ago you had occasion to note that "cars
are not as big as mountains"; then you committed this statement to rote
memory; and in imagining the story, you retrieved this fact, and made use
of it in constructing your image? A most unlikely theory. Or did it happen
instead as a consequence of some introspectively inaccessible interactions of
the symbols which were activated in your brain? Obviously the latter seems
far more likely. This knowledge that cars are smaller than mountains is not
a piece of rote memorization, but a piece of knowledge which can be
created by deduction. Therefore, most likely it is not stored in any single
symbol in your brain, but rather it can be produced as a result of the
activation, followed by the mutual interaction, of many symbols-for
example, those for "compare", "size", "car", "mountain", and probably
others. This means that the knowledge is stored not explicitly, but im-
plicitly, in a spread-about manner, rather than as a local "packet of infor-
mation". Such simple facts as relative sizes of objects have to be assembled,
rather than merely retrieved. Therefore, even in the case of a verbally
accessible piece of knowledge:;, there are complex inaccessible processes
which mediate its coming to the state of being ready to be said.
We shall continue our exploration of the entities called "symbols" in
different Chapters. In Chapters XVIII and XIX, on Artificial Intelligence,
we shall discuss some possible ways of implementing active symbols in
programs. And next Chapter, we shall discuss some of the insights that our
symbol-based model of brain activity give into the comparison of brains.Brains and Thoughts^365