Chapters Six to Ten deal with the boundaries of free choice. Self-determination and self-ownership are crucial to modern conceptions of the person, but what these terms mean, and what kind of social organisation they imply, is obviously contentious. The idea that liberty requires a cloak of paternalism is accepted by all but the most uncompromising libertarians and anarchists, and is a crucial principle of social welfare. But how thick should that cloak be and what is its appropriate design? How self-determining and self-owning are we really? How should we balance paternalism with liberty, security with autonomy? How far should we tip the balance in one direction or the other? When is autonomy enhanced by paternalism and when is it hindered?

We will tackle these questions repeatedly from a number of angles over this and the next four chapters. Since autonomy is central to our approach, we begin with one of its most celebrated defences and so on three issues dealing with harm to others and harm to oneself. It is Mill's utilitarian liberalism that offers a perennial starting point for such discussions and so provides the framework for this chapter.

The harm principle

For a century and a half, Mill has been crucial to any discussion of choice and paternalism, his ‘harm principle’ being one of the central tenets of liberalism – for recent critiques, see Jacobson (2000) and Holtug (2002).

According to Mill (1962, pp 135-8), we are entitled to interfere with the actions of individuals for reasons of self-protection only. If someone is harming another, we may take steps to prevent them, whether by impeding their actions or compelling them to perform actions whose non-performance would otherwise be harmful. But if someone is acting, or neglecting to act, in ways that create harm or diswelfare for himself alone, we are not entitled to force him to behave differently. We may entreat that person, but we cannot compel them without violating their personal sovereignty, a violation impermissible on utilitarian grounds since Mill regards the freedom of individuals to live as they see best, so long as they do not harm others, as the basis of a good society (Berlin, 1991; Ten, 1991).