protected boolean isConsistent(OWLOntologyManager manager, OWLOntology o)
      throws OWLReasonerException {
    OWLReasoner reasoner = JcelReasonerManager.getInstance().getJcelReasoner(manager);
    this.reasoner = reasoner;

    reasoner.clearOntologies();
    reasoner.loadOntologies(Collections.singleton(o));
    reasoner.classify();

    boolean ret = reasoner.isConsistent(o);
    return ret;
  }