The literature concerning the possibility and desirability of using new pharmacological and possible future genetic techniques to enhance human characteristics is well-established and the debates follow some well-known argumentative patterns. However, one argument in particular stands out and demands attention. This is the attempt to tie the moral necessity of moral enhancement to the hypothesised risks that allowing cognitive enhancement will bring. According to Persson and Savulescu, cognitive enhancement should occur only if the risks they think it to poses are (...) mitigated by moral enhancement. By this they mean the compulsory and universal amplification of the disposition of altruism and the inflation of our sense of fairness, by chemical and/or genetic means. Their claim is important, intriguing and unsettling. This paper focuses on three central, but relatively neglected, features of their argument. First, there is a pernicious ambiguity in the language of ‘risk’ used by Persson and Savulescu where they tend to conflate ‘risk’ and ‘uncertainty’. Second, their use of the lottery analogy to render their position more plausible is unconvincing. It tends to distort rather than illuminate the relevant considerations. Third, Persson and Savulescu do not adequately take into account the social and individual benefits that enhancing cognition could have. If they did, it would be apparent that those benefits alone would outweigh the considerations used to justify accompanying CE with ME. (shrink)