The scope of self-sovereignty

Mill writes that the object of On Liberty is “to assert one very simple principle . . . that the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not a sufficient warrant.” Mill concludes this famous paragraph by writing: “Over himself, over his own body and mind, the individual is sovereign.”

The metaphor of sovereignty over self is powerful, and it captures an essential aspect of Mill’s liberalism. Each of us is entitled to govern the domains of our own minds and bodies, free from coercive intrusion. We are entitled to determine what takes place in our minds, what happens to and in our bodies, and how to use our minds and bodies for our own benefit. We are entitled to determine what to think about, what to read, what to experience in art and music, what moods to try to be in, what to daydream, what imaginary conversations to have, how to pray, whether to pray at all, what to reflect on and wonder about. We are entitled to determine what to put into our bodies and how to use our bodies for health, work, and pleasure, to determine what to eat, how to exercise, how to care for our personal hygiene, what positions to sleep in, what sexual acts to consent to, and whether to have sex at all. Obviously, though, we don’t have the right to do whatever we want with our minds and bodies, regardless of its impact on others. We don’t have the right to jump out of a window regardless of who might be below. If there were a mind-altering drug that turned us into clever and elusive serial killers, we wouldn’t have the right to take it. Self-sovereignty has limits. What are they?