  There is another recent argument against rational egoism (Rachels and Alter 2005, Tersman 2008, and especially de Lazari-Radek and Singer 2014).  (1) Believing that rational egoism is true increases my reproductive fitness, whether or not rational egoism is true. (2) Therefore my belief that rational egoism is true (or, better, that rational egoism appears to me true upon reflection) does not help to justify rational egoism, since I would have that belief whether or not rational egoism is true. (3) For some other normative beliefs (such as belief in utilitarianism), having the belief does not increase reproductive fitness.  (4) Therefore my belief that (say) utilitarianism is true can help justify utilitarianism.  (Without (3) and (4), there is no argument against rational egoism in particular.)