It is astonishing, linguist Noam Chomsky tells us, that we know
anything at all. Our access to the external world is limited to
the five senses and our knowledge of the world is vastly
underdetermined by the information we derive from those senses.
From the same body of evidence we can derive any number of
theories, which is why we see God, witchcraft, and
thermodynamics all called upon to explain the same phenomena. On
the other hand, we are provided with a wealth of information
through our senses, probably too much. In order to make sense of
any of it at all, in order to even begin theorizing about the
nature of the world, we need to disregard most of what we see,
touch or feel. We need some means of paying attention to the
matter at hand, of heeding objects and disregarding shadows.
What is knowledge? Some people try to characterize it as a type
of belief that is sufficiently justified. Others say that
knowledge exists when our beliefs correspond with reality. Still
others characterize knowledge as continu