logic and the method of inheritance used in
&gt; &gt; frame-based systems.  A logician, however, would reply that inheritance is
&gt; &gt; the oldest of all rules of inference;  it was introduced by Aristotle for
&gt; &gt; syllogisms, and it is a derived rule in every modern system of logic.
&gt; &gt; The methods of unification used in many logic-based systems implement
&gt; &gt; inheritance in ways that are equivalent to or more general than frame
&gt; &gt; systems.  Rather than being a competitor, the sys