Freedom of expression is an essential component of freedom of thought.
Without the effort of saying what we think, of trying to communicate it to others, we cannot know what we really think. And it is only through dialogue with others that our own ideas can come into focus - and change in the process. A stark example of this everyday phenomenon came for me a few years ago when I wrote a book about Noam Chomsky's political writings. It was only after Chomsky's Politics had gone to press that I fully understood some of the things that I had been groping after in the writing of the book. It was only then, for example, that I identified the crucial sentence in Chomsky's work which illuminated everything else.