Economists are traditionally hostile to paternalism; public policy-makers and legal academics tend to be as well. Traditional objections to paternalism center on individual autonomy and the freedom to choose, on individuals' ability to learn from their mistakes, and on knowledge problems to which central planners are subject. More recently, in response to empirical demonstrations that people are vulnerable to a variety of cognitive and emotional biases in decision-making, anti-paternalists suggest that such central planners or experts are just as vulnerable. Each of these objections, though superficially plausible, nevertheless is challenged by empirical findings in psychology and cognitive science. Part of the objection to paternalistic interventions stems from traditional assumptions about the evils of paternalistic intervention per se. The strongest traditional assumption is the libertarian perspective that individuals know their own preferences and are better than any third party at choosing among alternatives to obtain the appropriate outcome.