  When we give moral advice, we morally ought to advise in the best way we can. That is, we should advise in the way we advise in the best world open to us. When things go smoothly, our advice will be true…But when things go awry, we may find that to advise in the best possible way, we must give false advice. Reflection on a more extreme case should make this clear. Suppose an ornery child always does the opposite of what we tell him to do. Suppose we know that he ought to turn right, and that hundreds of lives depend upon it. Should we tell him to turn right? Obviously not.