ocumentation "AXIOM: Every class is a subclass of itself.")
&gt; &gt;
&gt; &gt; (forall (?class)
&gt; &gt;        (=&gt; (Class ?class)
&gt; &gt;        (subclass-of ?class ?class)))
&gt; &gt;
&gt; &gt; ;; Axioms for the *predicate* "Entity".  It turns out to be convenient
&gt; &gt; ;; to introduce "Entity" as both a predicate true of all entities and
&gt; &gt; ;; as a constant denoting the class of entities.
&gt; &gt;
&gt; &gt; (documentation "AXIOM: There are entities.")
&gt; &gt;
&gt; &gt; (exists (?x) (