John Stuart Mill’s On Liberty is a short book of five chapters; the handout includes a selection from ch. I (which is Mill’s introduction) and the whole of ch. IV. If you’d like to read more, you can find the text in many places on line. I’ve included it in the source browser on the course Moodle site; that version has the handout’s selections marked, so it will show the context of the selections from the first chapter.
On Liberty may be best known for what Mill says about the freedom of expression (that discussion appears in ch. II, which is about a third of the whole book). Although his discussion of freedom of expression is certainly important for the philosophy of law, we will instead be discussing a broader claim Mill makes concerning the justification of legal restrictions on actions of any sort. Mill’s position is a strong one, so not everyone agrees with it; but it is stated sharply enough that it can be helpful to think of opposing views in relation to it.
He states his position at the beginning of the main selection from his introductory chapter. He has something to say there also about its justification. Notice, in particular, his comments about utilitarianism (Mill is probably the best known proponent of utilitarian moral theory).
In Ch. IV, Mill presents his view and its justification at greater length. Think about his description of his view as well as his justification because even someone sympathetic with his position can wonder exactly how the line is to be drawn between the actions that can and those that cannot be legitimately restricted on Mill’s view. These questions might be grouped under three headings:
• What sort of actions count as “self-regarding” (to use Mill’s phrase)?
• What sorts of effects of our actions on others count as harm?
• How far does the exception Mill makes for children extend?
Since the cases where it is most difficult for Mill to justify his principle are likely to lie near these boundaries, thinking about where its boundaries lie can also be a good way of approaching the question of how successful Mill has been in establishing his principle. That is, you can ask yourself whether he has provided good reason for exempting from legal restriction as wide a range of actions as he would like. (Of course, the opposite question is worth asking, too: has Mill gone as far as he should have in this respect or does he allow too much legal restriction?)