  The concept of luck is a curious one (Dennett 1984, 92; see also Pritchard 2005, 125–133; Pritchard and Whittington 2015). To avoid various pitfalls, it helps to distinguish thin and thick notions of luck (as suggested by Hurley 2002, 79–80; Hurley 2003, 107–109; Vallentyne 2006, 434). To say that something—whether a choice or an outcome (other than choice) (Olsaretti 2009; Scheffler 2003, 18–19)—is a matter of thin luck for someone is to say merely that this person does not stand in a certain moral relationship to a certain object, where such moral relationship essentially involves this individual in his or her capacity as a rational agent. To say that something is a matter of thick luck is to say this and to commit oneself to a certain account of the non-moral properties in virtue of which this moral relationship obtains. Accordingly, a thick concept of luck is a more specific version of the corresponding thin concept of luck. In either case, to say that something is a matter of luck for someone, in the sense of “luck” that is relevant to justice, is to imply that it affects this person’s interests for good or bad (see, however, Sher’s discussion (2014, 20–34) of whether the relevant objection to luck applies to people’s absolute or comparative distributive positions).