 don't match reality ...
    and our logicians may feel justified in snickering about our ineptitude.
    But a computer agent which follows necessary rules has no less problem
    than we humans.  A computer agent is called upon to generate symbols
    from signs that are read from the external world and then to apply
    the formulas of logic which ignore any confusion as to for-what
    those symbols stand.  Presumably we are to contrive that the
    computer tests its hypothesis against reality and that