Cass Sunstein's contention that evolutionary explanations for behavioural economic phenomena are of limited relevance to public policy – and his support for soft paternalism – rests on his view that policymakers ought to be pursuing increases in some overarching social planning conception of welfare. In this reply to Sunstein, I argue that people have differing and multifarious desires in life, with the social planner's conception of welfare being, at best, perhaps only a partial consideration for most people. The phenomena that behavioural economists and psychologists have empirically observed may well facilitate people in the pursuit of their own desires in life. Consequently, paternalistic manipulation or coercion to save people from themselves is questionable in the behavioural public policy space, but government intervention is warranted when one party implicitly or explicitly uses these phenomena to exploit others.
