Mill on the Liberty of Thought and Discussion

This chapter discuses Chapter Two of John Stuart Mill’s On Liberty, ‘On the Liberty of Thought and Discussion’, which is the best-known defence of free speech in the philosophical canon. It suggests that Mill’s argument in chapter two of On Liberty is a distinctively epistemic argument, and one which relies on a specific conception of man’s cognitive nature and the character of human knowledge. There is a strong connection between Mill’s Freedom of Discussion Principle and the way in which human beings come to know the world. The chapter then identifies what Mill means to rule out by his argument—what, in short, freedom of discussion is freedom from—and what he means to rule in. It also considers the relation between the Freedom of Discussion Principle and its better known sibling, the Harm Principle, and the conditions under which these principles are applicable.