Most countries allow their citizens to smoke cigarettes, get intoxicated, and eat unhealthy food – despite the harms that such behaviors may bring to the individual's health and to the social and economic interests of the state. Yet taking certain narcotics, selling one's organs, and driving without a seat-belt are often prohibited by law. Is this an arbitrary distinction, or is there a principled reason for these diverging attitudes? What can government legitimately prohibit its citizens from doing to their own bodies -- and what can it legitimately compel them to do? John and Ken are joined by Cécile Fabre from the University of Oxford, author of Whose Body is it Anyway? Justice and the Integrity of the Person.