The doctrine that an act is never immoral when the agent thinks it right has the drawback (or the advantage) that it excuses almost all the acts which would be commonly condemned. Very few people deliberately do what, at the moment, they believe to be wrong; usually they first argue themselves into a belief that what they wish to do is right. They decide that it is their duty to teach so-and-so a lesson, that their rights have been grossly infringed that if they take no revenge there will be an encouragement to injustice, that without a moderate indulgence in pleasure a character cannot develop in the best way, and so on and so on. Yet we do not cease to blame them on that account. Of course it may be said that a belief produced by a course of self-deception is not a genuine belief, and that the people who invent such excuses for themselves know all the while that the truth is the other way. Up to a point this is no doubt true, though I doubt if it is always true. There are, however, other cases of mistaken judgment as to what is right, where the judgment is certainly genuine, and yet we blame the agent. These are cases of thoughtlessness, where a man remembers consequences to himself, but forgets consequences to others. In such a case he may judge correctly and honestly on all the data that he remembers, yet if he were a better man he would remember more data. Most of the actions commonly condemned as selfish probably come under this head. Hence we must admit that an act may be immoral, even if the agent quite genuinely judges that it is right. (§ 21 ¶ 1)

Unreflecting acts, again, in which there is no judgment as to right or wrong, are often praised or blamed. Acts of generosity, for example, are more admired when they are impulsive than when they result from reflection. I cannot think of any act which is more blamed when it is impulsive than when it is deliberate; but certainly many impulsive acts are blamed—for example, such as spring from an impulse of malice or cruelty (§ 21 ¶ 2)