  Altruism is usually defined as acting out of a concern for the well-being of others (Nagel 1970; Scott &amp; Seglow 2007). Why might one think that such actions are morally good? Two main answers are available. The first is that altruism is intrinsically good and to be contrasted with morally bad characteristics and motivations, in particular selfishness. The second (which is not incompatible with the first) says that altruism is good because of its positive effects, not only its direct effects on the person to whom the altruism is directed but also its indirect effects on society. Both answers have considerable plausibility. Many examples of acting out of disinterested concern for the well-being of others do seem to be clear-cut cases of moral virtue. And it seems likely that, all other things being equal, a society with more altruistic acts would be a better place to live than one with fewer.