;If past experience is a fair sample of
possible experience, then the knowledge gained in it applies
to present experience.&quot;  This is the mechanism that allows a
knowledge base to be carried across gulfs of experience that
are indifferent to the effective contents of its rules.

Here are the details of how this works out in the &quot;Rainy Day&quot; example.
Let us consider a fragment K(0) of the reasoner's knowledge base that
is logically equivalent to the conjunction of two rules.

        K(0)  =  (