public static TruthValue strengthenTruthValue(TruthValue tv1, TruthValue tv2) {
    if (((tv2 == Logic.TRUE_TRUTH_VALUE) ||
        (tv2 == Logic.FALSE_TRUTH_VALUE)) &&
        ((tv1 == Logic.DEFAULT_TRUE_TRUTH_VALUE) ||
         (tv1 == Logic.DEFAULT_FALSE_TRUTH_VALUE))) {
      if ((tv1 == Logic.TRUE_TRUTH_VALUE) ||
          (tv1 == Logic.DEFAULT_TRUE_TRUTH_VALUE)) {
        return (Logic.TRUE_TRUTH_VALUE);
      }
      if ((tv1 == Logic.FALSE_TRUTH_VALUE) ||
          (tv1 == Logic.DEFAULT_FALSE_TRUTH_VALUE)) {
        return (Logic.FALSE_TRUTH_VALUE);
      }
    }
    return (tv1);
  }