I owe a lot to Gary Mahoney.

He was the campus conservative back in the middle ’70s, when I was a student at the University of Southern California and we went at it hammer and tongs a few times on the opinion pages of the Daily Trojan. I no longer recall the details of our disagreements. What I do remember is realizing that he was good and that I had to up my game — tighten my reasoning, sharpen my logic — if I hoped to stay in the ring with him.

He made me better in the same way college itself did. Nearly five decades later, I value those years less for any specific thing I learned in class than for the fact that I learned how to think. Not “what” to think, but how, i.e., how to gather and evaluate information, how to analyze and extrapolate from it, how to defend my ideas in the scrum of intellectual conflict.

That’s a lesson students will be denied if Republicans like Ron DeSantis get their way. Last week, Florida’s governor signed a bill requiring the state’s public colleges and universities to survey students and faculty on their ideological beliefs. The aim, he claims, is to prevent schools from “indoctrinating” students. DeSantis has hinted that those failing to show “intellectual diversity” will face budget cuts.

You may gauge the sincerity of his commitment to that diversity by the fact that this comes two weeks after he pushed to ban the teaching of critical race theory — an academic framework originated by legal scholars over 40 years ago. Like other states where similar restrictions are becoming law, Florida seeks not to further intellectual diversity, but to prevent it.

Meaning, it aims to protect kids raised on mom and dad’s steady diet of Fox “News” and Breitbart from the shock of having any ideas they’ve thereby imbibed challenged in the outside world. Which is hypocritical on its face. After all, conservatives once — not unreasonably — chided liberals for trying to bubble-wrap students with trigger warnings and safe spaces. Now they use force of law to do the very same thing.

It should go without saying that it’s none of the state’s business what you or I think. It should be likewise obvious that this law will stifle debate and muzzle instructors and is thus antithetical to the mission of our colleges and universities.

There is no mystery why conservatives find education dangerous. A 2015 Pew Research Center study quantified that the better educated one is, the more likely one is to hold liberal beliefs. But I’d argue, contrary to what conservatives seem to feel, that’s not because of bullying professors shouting left-wing dogma. Rather, it’s because once you learn how to think, you’re less susceptible to thin reasoning and easy answers. And increasingly, that’s all conservatism’s got.

That may not have been true — or at least, may have been less true — decades ago. But back then, the right had some intellectual underpinning, had yet to devolve into the twitching id of perpetual resentment now on daily display. I mean, is anyone overawed by the profundity of Matt Gaetz and Marjorie Taylor Greene? How about Louie Gohmert? Or even Ron DeSantis?

An opinion one can’t defend — using actual facts and recognizable reason — is an opinion not worth having. At some level, conservatives must know they fail that standard, so they work to undermine it instead, to make the world safe for ignorance.

Teach your children well, the songwriter said. But this is the opposite of that.

I like to think Gary Mahoney would agree.

Leonard Pitts Jr. is a columnist for the Miami Herald. lpitts@miamiherald.com