 The nonidentity problem seems to show, as Parfit notes, that the moral principle we seek – the “Theory X” – “will not take a person-affecting form” (Parfit 1987, 378). The obvious alternative is a theory that is impersonal at least in part. Both totalism and averagism fit that description. The difficulty is that both views raise still other problems. Totalism can easily explain how an act that makes things worse for no existing or future person can be wrong. But it immediately generates– for example – the repugnant conclusion (Parfit 1987, 381–90; see also  repugnant conclusion).  Averagism does a good job with the nonidentity problem and the repugnant conclusion but implausibly seems to prohibit bringing an additional happier-than-average child into existence if it so happens that prior generations have had especially wonderful lives (Parfit 1987, 420; Feldman 1995, 192–93). It also generates problematic results when applied to the case Temkin calls “Hell Three” (Temkin 2012, 319–320). Surely, a situation that is hellish for everyone who exists is not improved by the addition of still more people whose lives aren’t quite so hellish but still far less than worth living. Totalism and averagism, moreover, face objections based on considerations of justice, fairness and equality. Fashioning a cogent response to the nonidentity problem that does not create at least as many problems as it solves has thus emerged as a critical challenge in population ethics.