"rubbing off" instances from classes, in the way that one makes rubbings
from brasses in churches, has enabled you to represent the situation, and
has freed you from the need to remain faithful to the real world. The fact
that symbols can act as templates for other symbols gives you some mental
independence of reality: you can create artificial universes, in which there
can happen nonreal events with any amount of detail that you care to
imbue them with. But the class symbols themselves, from which all of this
richness springs, are deeply grounded in reality.
Usually symbols play isomorphic roles to events which seem like they
could happen, although sometimes symbols are activated which represent
situations which could not happen--for example, watches sizzling, tubas
laying eggs, etc. The borderline between what could and what could not
happen is an extremely fuzzy one. As we imagine a hypothetical event, we
bring certain symbols into active states-and depending on how well they
interact (which is presumably reflected in our comfort in continuing the
train of thought), we say the event "could" or "could not" happen. Thus the
terms "could" and "could not" are extremely subjective. Actually, there is a
good deal of agreement among people about which events could or could
not happen. This reflects the great amount of mental structure which we all
share-but there is a borderline area where the subjective aspect of what
kinds of hypothetical worlds we are willing to entertain is apparent. A
careful study of the kinds of imaginary events that people consider could
and could not happen would yield much insight into the triggering pat-
terns of the symbols by which people think.
Intuitive Laws of PhysicsWhen the story has been completely told, you have built up quite an
elaborate mental model of a scene, and in this model all the objects obey
physical law. This means that physical law itself must be implicitly present
in the triggering patterns of the symbols. Of course, the phrase "physical
law" here does not mean "the laws of physics as expounded by a physicist",
but rather the intuitive, chunked la\\s which all of us have to have in our
minds in order to survive.
A curious sidelight is that one can voluntarily manufacture mental
sequences of events which violate physical law, if one so desires. For
instance, if I but suggest that you imagine a scene with two cars approach-
ing each other and then passing right through each other, you won't have
any trouble doing so. The intuitive physical laws can be overridden by
imaginary laws of physics; but how this overriding is done, how such
sequences of images are manufactured-indeed what anyone visual image
is-all of these are deeply cloaked mysteries-inaccessible pieces of knowl-
edge.
Needless to say, we have in our brains chunked laws not only of how
inanimate objects act, but also of how plants, animals, people and societies
act-in other words, chunked laws of biology, psychology, sociology, and so(^362) Brains and Thoughts