Four Types of Moral Luck
Thomas Nagel identified four kinds of moral luck in his essay. The kind most relevant to the above example is "resultant moral luck".
Resultant Moral Luck (Consequential)
Resultant moral luck concerns the consequences of actions and situations. In the above example, both drivers were affected by resultant moral luck in that a particular set of circumstances turned out in two different ways: in one situation, a pedestrian appeared on the road; in the other, the pedestrian did not.
Circumstantial Moral Luck
Circumstantial moral luck concerns the surroundings of the moral agent. The best-known example is provided in Nagel's essay. Consider Nazi followers and supporters in Hitler's Germany. They were and are worthy of moral blame either for committing morally reprehensible deeds or for allowing them to occur without making efforts to oppose them. But, if in 1929, those people were moved to some other country, away from the coming hostilities by their employers, it is quite possible that they would have led very different lives, and we could not assign the same amount of moral blame to them. It is down, then, to the luck of the circumstances in which they find themselves.
Constitutive Moral Luck
Constitutive moral luck concerns the personal character of a moral agent. There can be little argument that education, upbringing, genes and other largely uncontrollable influences shape personality to some extent. Furthermore, one's personality dictates one's actions to some extent. Moral blame is assigned to an individual for being extremely selfish, even though that selfishness is almost certainly due in part to external environmental effects.
Causal Moral Luck
Causal moral luck, which equates largely with the problem of free will, is the least-detailed of the varieties that Thomas Nagel describes. The general definition is that actions are determined by external events and are thus consequences of events over which the person taking the action has no control. Since people are restricted in their choice of actions by the events that precede them, they should not be held accountable or responsible for such actions.
Thomas Nagel has been criticized[who?] for including causal moral luck as a separate category, since it appears largely redundant. It does not cover any cases that are not already included in constitutive and circumstantial luck, and seems to exist only for the purpose of bringing up the problem of free will.[1]