 Mill begins his defense of basic liberties with a discussion of freedom of expression. He thinks that there is general agreement on the importance of free speech and that, once the grounds for free speech are understood, this agreement can be exploited to support a more general defense of individual liberties (I 16; III 1). So his defense of expressive liberties is important not only in its own right but also insofar as it lays the foundation of his liberal principles.