Bernard Williams thought that there is moral luck.
Imagine the following example. Suppose that a young painter, Gaugin, leaves his wife and children in order to become a great artist. When he leaves, it is uncertain whether he will be successful. The only thing that could justify the morality of his decision is success itself. At the time of his action, he cannot justify his action to others. Moral justification of his action is "essentially retrospective". Because at the time that he left it was impossible to know in advance whether he would be successful, there is no possible justification at the time of his choice. It is not as if he is following a rule that says "A person can neglect loved ones if he is reasonably convinced that he is a great artist." Williams says that because we have no way to know if a person will be great in advance, such a rule would be ridiculous. We cannot simply appeal to art professors or art experts. Even if Gaugin was certain that he would succeed, such a belief could only be known after success was actually achieved. Such a feeling or such a belief cannot justify Gaugin's decision to leave his family. Williams says that if Gaugin would have failed, then his choice to leave his family was not justified. Because Gaugin succeeded, his action was justified.
Williams thinks that evidence for this is that when we feel, we feel agent regret, which means that we blame ourselves. When we succeed, we do not blame ourselves for how things turned out. If we fail, we regret our actions, especially if we could have acted otherwise. We feel this regret even if we were justified to act as we did at the time that we acted. This is because there are sometimes unexpected outcomes to our actions. Imagine a truck driver who is very careful when he drives. He keeps his truck is good condition and obeys all traffic laws. One day, he is slowly backing up when a young girl darts out into his path and is killed. Although he was careful, the unexpected outcome of his action was the death of a girl. The truck driver will regret his actions even if outside observers recognize that the truck driver took all necessary precautions. The truck driver may even seek recompense or restitution.
Nagel objects to this. Nagel says that perhaps the agent will regret his causal responsibility. However, this regret has not been shown to be moral. Just because a person's feelings are vulnerable to luck, this does not entail that morality itself is vulnerable to luck. If, for example, Gaugin's choice to leave his wife were actually moral, then this would, "...imply the truth of a hypothetical judgment made in advance, of the form 'If I leave my family and become a great painter, I will be justified by success'...", which is obviously ridiculous. Williams responds that just because a choice is or is not justified at the time does not settle whether the choice is ultimately morally justified. Another tack may be to say that if someone can be "sure enough" about the justification of an action beforehand, then the chance is justified. Maybe Gaugin really did have good enough reasons to think that he would be successful. If he was "sure enough", then perhaps his choice to leave his family could have been justified before he knew for certain that he would be successful. Dr. James notes that in such a case, this looks no different than a person with delusions of grandeur.