This chapter examines two ways in which liberal thinkers have appealed to claims about disagreement in order to defend a principle of free speech. One argument, from Mill, says that free speech is a necessary condition for healthy disagreement, and that healthy disagreement is conducive to human flourishing. The other argument says that in a community of people who disagree about questions of value, free speech is a necessary condition of legitimate democratic government. We argue that both of these arguments, (...) in their standard guises, are premised upon contestable views about the realpolitik of disagreement in a liberal society. (shrink)