Willingness to permit the expression of bigotry and stupidity, and to denounce or ignore it without censoring it, is the only appropriate expression of the enlightened conviction that the proper ground of belief is reason and evidence rather than dogmatic acceptance.

I find it a personal affront to be protected from the expression of such claims by others—thinking as a person with a mind of my own. But it is also an affront that the state should have the power to silence anyone—and therefore to silence me, if I were to start spouting equally contemptible nonsense. The censorship of a fanatical bigot is an offense to us all.

The same can be said about the pressures to control racially offensive and sexist expression in the United States. And here again I am not just talking about the more ridiculous excesses of political correctness, but about the prohibition of hard-core, intentional expressions of hostility. The situation where those who hold such opinions or attitudes are prevented from expressing them publicly seems to me extremely unhealthy, with its suggestion that the opposite, right-thinking view is a dogma that cannot survive challenge, and cannot be justified on ordinary rational and evidential grounds. The status of blacks and women can only be damaged by this kind of protection.

(Thomas Nagel, “Personal Rights and Public Space,” Philosophy & Public Affairs 24 [spring 1995]: 83-107, at 98-9)