Chapter 2 of Mill’s On Liberty is reconstructed as a complex argument for freedom of discussion; it consists of three subarguments, each possessing illative and dialectical components. The illative component is this: freedom of discussion is desirable because it enables us to determine whether an opinion is true, whereas its denial amounts to an assumption of infallibility; it improves our understanding and appreciation of the supporting reasons of true opinions, and our understanding and appreciation of their practical or emotional meaning; (...) it enables us to understand and appreciate every side of the truth, given that opinions tend to be partly true and partly false and people tend to be one-sided. The dialectical component consists of replies to ten objections, five in the first subargument, three in the second, one in the third, and one general. An analysis of Mill’s argument suggests that it is a contribution to argumentation theory; it advocates and practices a dialectical approach; its reconstruction and analysis are a contribution to argumentation theory; and it raises in a striking manner the issue of the relationship between epistemology and argumentation theory. (shrink)