In a blog post here a few years ago (Friedman and Socialism), I mentioned a 1991 Liberty article by Friedman that I remembered where he said he was in favor of liberty and tolerance of differing views and behavior because we cannot know that the behavior we want to outlaw is really bad. In other words, the reason we should not censor dissenting ideas is not the standard libertarian idea that holding or speaking is not aggression, but because the we can’t be sure the ideas are wrong. This implies that if we could know for sure what is right and wrong, it might be okay to legislate morality, to outlaw immoral or “bad” actions.
I regard the basic human value that underlies my own [libertarian] beliefs as tolerance, based on humility. I have no right to coerce someone else, because I cannot be sure that I am right and he is wrong.
… If we see someone doing something wrong, someone starting to sin (to use a theological tern) let alone just make a simple mistake, how do we justify not initiating coercion? Are we not sinning if we don’t stop him? Only two bases for a negative answer occur to me that make any sense. One–which I regard largely as largely an evasion–is that there’s no virtue in his not sinning if he’s not free to sin. That may be true. But then, that doesn’t apply to me. It may be no virtue for him. That doesn’t mean I should let him sin: am I not sinning when I let him sin? How do I justify letting him sin? I believe that the more persuasive answer is, can I be sure he’s sinning? Can I be sure that I am right and he is wrong? That I know what sin is?
Note also that this article is one of the sources where Friedman alleges Mises stormed out of the Mont PÃ¨lerin Society meeting in 1947, during a discussion about the progressive income tax, exclaiming, “You’re all a bunch of socialists.” (Also recounted in Lew Rockwell’s Mises and Liberty; Long’s Mises as Radical, and in Guido Hülsmann’s Mises: The Last Knight of Liberalism, p. 871.)
Friedman also here reiterates his positivist methodology, and opposition to Misesian praxeology in economics and Randian principle in libertarianism and philosophy. Based on his “tolerant” (which some might deride as unprincipled) views, he again reiterates his support for educational vouchers and the negative income tax.
Friedman was a great libertarian (in fact he was one of the main three or four influences on my own libertarian development), but this is not him at his best.
For further discussion, see Hoppe’s, “The Western State as a Paradigm: Learning from History” (discussing Friedman’s views on “intolerance”; Milton Friedman & Walter Block, “Fanatical, Not Reasonable: A Short Correspondence Between Walter Block and Milton Friedman (on Friedrich Hayek)“; Hoppe’s 1997 Mont Pelerin Society speech, “The Future of Liberalism. A Plea for a New Radicalism“; and Mises’s 1946 memo, “Observations on Professor Hayek’s Plan“; Murray N. Rothbard, “Milton Friedman Unraveled“; and Walter Block, “Milton Friedman, RIP.”