Here is an excerpt:
Where a significant aspect of what someone does depends on factors beyond his control, yet we continue to treat him in that respect as an object of moral judgment, it can be called moral luck. Such luck can be good or bad. And the problem posed by this phenomenon, which led Kant to deny its possibility, is that the broad range of external influences here identified seems on close examination to undermine moral assessment as surely as does the narrower range of familiar excusing conditions. If the condition of control is consistently applied, it threatens to erode most of the moral assessments we find it natural to make. The things for which people are morally judged are determined in more ways than we at first realize by what is beyond their control. And when the seemingly natural requirement of fault or responsibility is applied in light of these facts, it leaves few pre-reflective moral judgments intact. Ultimately, nothing or almost nothing about what a person does seem to be under his control.
Why not conclude, then, that the condition of control is false--that it is an initially plausible hypothesis refuted by clear counter-examples? One could in that case look instead for a more refined condition which picked out the kinds of lack of control that really undermine certain moral judgments, without yielding the unacceptable conclusion derived from the broader condition, that most or all ordinary moral judgments are illegitimate.
What rules out this escape is that we are dealing not with a theoretical conjecture but with a philosophical problem. The condition of control does not suggest itself merely as a generalization from certain clear cases. It seems correct in the further cases to which it is extended beyond the original set. When we undermine moral assessment by considering new ways in which control is absent, we are not just discovering what would follow given the general hypothesis, but are actually being persuaded that in itself the absence of control is relevant in these cases too. The erosion of moral judgment emerges not as the absurd consequence of an over-simple theory, but as a natural consequence of the ordinary idea of moral assessment, when it is applied in view of a more complete and precise account of the facts. It would therefore be a mistake to argue from the unacceptability of the conclusions to the need for a different account of the conditions of moral responsibility. The view that moral luck is paradoxical is not a mistake, ethical or logical, but a perception of one of the ways in which the intuitively acceptable conditions of moral judgment threaten to undermine it all.
The entire article is here.