According to Williams, Aristotle claim, in Nicomachean ethics II.4, that "The virtuous agent chooses virtuous actions 'for their own sake'" should be taken as meaning different things, according to which virtues are in question.
If it is any virtue but justice, temperance1. or courage, choosing the act for its own sake means choosing it for at least one of a certain type or range of reasons, X, "where the type X is tied (both positively and negatively) to the virtue in question", but is not "the same notion" (p. 18).
If the virtue in question is justice, choosing the act for its own sake means, roughly, choosing it because it is just. And if the virtue in question is temperance or courage, it can mean only something "quite special: something like doing a certain thing in a certain situation to display or develop one's courage or self-control" (p. 19). In fact, courage and temperance just don't fit Aristotle II.4. account of acting virtuously at all.
That justice should emerge as a bit of an odd man out might not surprise us; Hume, after all, is right that there is something distinctive about it. But I do find something perverse in an interpretation of II.4 that not only makes justice a slightly special case but also makes courage and temperance not fit, the two virtues (along with justice) that Aristotle mentions time and again to illustrate his general claims about the virtues in Book II, and thereby (one might plausibly say) the two he is least likely to have forgotten about when claiming that the virtuous agent chooses virtuous actions "for their own sake."
For several reasons, some the same as Williams', some rather different (in particular connected with inculcating the virtues in children), I too have long believed that "The V agent chooses what is V for X reasons" is a good way of understanding "The V agent chooses what is V 'for its own sake'." But I have always taken this in such a____________________