svoid philosophyBot1_enableAddSimplifier(PhilosophyBot1 bot) {
  bot.addFactPreprocessor(fact -> {
    S rule = $x(bot.matchString("add simplifier $x", fact));
    if (rule == null) false;
    print("adding simplifier: " + rule);
    PairS p = tok_splitAtDoubleArrow_pair(rule);
    if (p == null) false;
    philosophyBot1_addSimplificationRule(bot, p.a, p.b);
    true;
  });
}