Since so many people seem to be confused on this point:
Free speech is the right to express ideas without coercion.
We must protect freedom of speech both because it is an aspect of individuals' right to liberty and dignity and because it is good for society to have a rich exchange of ideas.
It is important that we understand free speech broadly and protect it vigorously. But common misunderstandings inspire me to outline what free speech is not:
- Free speech is not just law, it is a principle, a social norm.
- Free speech is not just protection from government censorship, it is protection from coercion of all kinds. If there are things you cannot say because it might cost you professional opportunities in work unrelated to what you said, or it might lead to harassment or even violence, or it might prevent you from finding housing or medical care or other essential services, then that is no less coercive than a law. The rest of that XKCD cartoon is correct, but that first panel is dangerously wrong: where it says “free speech” it describes the First Amendment, not the principle of free speech.
- Free speech is not only a protection for nice speech, it is and must be a protection for icky speech too. Free speech is a right to say things that discomfort others.
- Free speech is not a right to speak in every space. It is a right to speak in the public sphere. One may also be invited into private spaces, and what one says there is subject to the same free speech principles, but that does not mean one has a right to barge into any space you want and demand to speak. Private spaces may set their own rules for participation.
- Free speech is not a right to freedom from criticism. The whole point is that one’s critics are free to speak, too.
- Free speech is not a right to say anything, it is a right to express ideas. It is not a license for lies, deceit, and fraud. It is not a license to conspire to commit crimes. It is not a license for slander, harassment, and threats. There is no legitimate personal right to those actions, they do not contribute to the public sphere of ideas, and there is a significant public interest in curtailing them.
This is not hard to understand. But things being what they are, I expect that I will have to expand and clarify this list over time.