(clear-theory [<theory>] [<implementation>])
Resets the specified theory, effectively removing definitions and other facts. Does not alter includees or includers of the specified theory.
<theory> may be any object acceptable to FIND-THEORY. If unspecified, the current theory is assumed (see IN-THEORY and *CURRENT-THEORY*.)
<implementation> is the name of an implementation, as given to IN-IMPLEMENTATION. It is used to disambiguate the <theory> argument if that theory is given as a symbol.