The central problem in the study of addiction is to explain why people repeatedly behave in ways they know are bad for them. For much of the previous century and until the present day, the majority of scientific and medical attempts to solve this problem were couched in terms of involuntary behaviour; if people behave in ways they do not want, then this must be because the behaviour is beyond their control and outside the realm of choice. An opposing tradition, which finds current support among scientists and scholars as well as members of the general public, is that so-called addictive...