According to much modern social psychology, behavioural economics and common sense, people's actions and beliefs are frequently the result of rapid intuitive thought rather than careful deliberation. Richard Thaler and Cass Sunstein, in their influential book, Nudge, synthesised the literature and used it as the basis for numerous policy ideas.1 Not least, they gave the word ‘nudge’ as a handy term to apply to all sorts of ways of taking advantage of people's psychological quirks without coercing or bribing them. But while Nudge was long on ideas and enthusiasm, it was short on conceptual clarity. The idea of a nudge was inconsistent with some of the policies Thaler and Sunstein endorsed and their account of nudging's relation to freedom and paternalism was flawed.

In Salvaging the concept of nudge, Yashar Saghai acts as a friendly critic who thinks nudging has plenty to offer the policy world but sees that it needs both conceptual clarity and ethical defence.² He wants to show how some of ways of taking advantage of people's psychology could leave them as free as before and he is especially concerned with what I would describe as a question of manipulation: …