John Stuart Mill’s On Liberty is far from a perfect book, but liberal-arts students used to read it a lot. I bet it was assigned in three or four of my courses when I was an undergraduate. Figuring out its strengths and weaknesses was part of the fun. When I ask students today, however, almost none has read it. The culture of free discussion and debate is declining, and with it liberty, on and off the campus.

What’s behind the decline? There are many factors, but among the most influential is that dead-end of modern philosophy called postmodernism, which has had two baneful effects. By teaching that reason is impotent—that it can’t arrive at any objective knowledge of truth, beauty, and justice because there is nothing “out there” to be known—postmodernism turns the university into an arena for will to power. All values are relative, so there is no point in discussing whether the most powerful values are true, just, or good. The crucial thing is that they are the most powerful, and can be played as trumps: do not offend me, or you will be in trouble. If we say it’s racist, then it’s racist. Don’t waste our time trying to ask, But what is racism?

Second, postmodernism devotes itself to what Richard Rorty called “language games.” For professors, especially, this is the most exquisite form of will to power, “a royal road to social change,” as Todd Gitlin (the rare lefty professor at Columbia who defends free speech) observes. So freshman girls became “women,” slaves turned into “enslaved persons,” “marriage” had to be opened to “same-sex” spouses, and so forth. Naming or renaming bespeaks power, and for decades we have seen this power rippling through American society. Now even sexual assault and rape are whatever the dogmatic leftists on and off campus say they are.