A production rules engine comprises: a class loader for loading a production rule ontology into a rule engine; a class loader for loading production rules into the rule engine, wherein a production rule comprises a rule and an action defined in the production rule ontology; instance creation logic for creating instances of production rules; a reasoner for executing the production rules and for locating an instance of a production rule having an inconsistency between an action to change the ontology and the existing ontology and for executing the production rules after inconsistencies have been fixed; a constraint engine for locating a solution to an inconsistent ontology; and a fixer for updating the inconsistent ontology with the located solution.