the first impression, which should have been wiped out when you learned it
was all untrue. Fantasy and fact intermingle very closely in our minds, and
this is because thinking involves the manufacture and manipulation of
complex descriptions, which need in no way be tied down to real events or
things.
A flexible, intensional representation of the world is what thinking is
all about. Now how can a physiological system such as the brain support
such a system?
The Brain's "Ants"The most important cells in the brain are nerve cells, or neurons (see
Fig. 65), of which there are about ten billion. (Curiously, outnumbering the
neurons by about ten to one are the glial cells, or glia. Glia are believed to
play more of a supporting role to the neurons' starring role, and therefore
we will not discuss them.) Each neuron possesses a number of synapses
("entry ports") and one axon ("output channel"). The input and output are
electrochemical flows: that is, moving ions. In between the entry ports of a
neuron and its output channel is its cell body, where "decisions" are made.
Brains and Thoughts
c"' ~",>-,--~dendritesFIGURE 65. Schematic drawing of a
neuron. [Adapted From D. Wooldridge, The
Machinery of the Brain (New York:
McGraw-Hill, 1963), p. 6.]339