Icontrast to processes which are supposed to carry out strictly deductive
reasoning. Processes which carry out deductive reasoning can be pro-
grammed in essentially one single level, and are therefore skimmable, by
definition. According to my hypothesis, then, imagery and analogical
thought processes intrinsically require several layers of substrate and are
therefore intrinsically non-skimmable. I believe furthermore that it is pre-
cisely at this same point that creativity starts to emerge-which would imply
that creativity intrinsically depends upon certain kinds of "uninterpretable"
lower-level events. The layers of underpinning of analogical thinking are,
of course, of extreme interest, and some speculations on their nature will
be offered in the next two Chapters.Articles of Reductionistic Faith
One way to think about the relation between higher and lower levels in the
brain is this. One could assemble a neural net which, on a local (neuron-
to-neuron) level, performed in a manner indistinguishable from a neural
net in a brain, but which had no higher-level meaning at all. The fact that
the lower level is composed of interacting neurons does not necessarily
force any higher level of meaning to appear-no more than the fact that
alphabet soup contains letters forces meaningful sentences to be found,
swimming about in the bowl. High-level meaning is an optional feature of a
neural network-one which may emerge as a consequence of evolutionary
environmental pressures.
Figure 107 is a diagram illustrating the fact that emergence of a higher
level of meaning is optional. The upwards-pointing arrow indicates that a
substrate can occur without a higher level of meaning, but not vice versa:
the higher level must be derived from properties of a lower one.FIGURE 107. Floating on neural activity, the symbol level of the brain mirrors the world.
But neural activity per se, which can be simulated on a computer, does not create thought; that
calls for higher levels of organization.,
I higher level ,
I of brain }
\ (symbol level) semt-
tsomorphtsm
(meaning)A optional link
.
I\world
\computer Isubstrate: brain'
( model of as collection )
\ neural network) isomorphism \ of neurons}
Church, Turing, Tarskl, and Others 571,
)