The CNN multipart series on the history of late-night television reminded me that Johnny Carson used to have the occasional English professor as a guest. Quite unthinkable today. A. L. Rowse of Oxford once boasted to me what a bore it was to appear on The Tonight Show. It may have been my most memorable encounter with the “humblebrag.”

But it was Richard Mitchell (1929–2002), the self-described “underground grammarian,” whose appearances with Carson made the most lasting impressions. He looked the part of an English prof: thick glasses, disheveled comb-over, nervously high-pitched voice, eloquent speech. He wasn’t an Ivy Leaguer — he taught at Glassboro State College (now Rowan University) in Glassboro, N.J. From his headquarters there, Mitchell launched missiles at whoever was paid to use his mind but did so poorly.

On Mitchell’s first visit to The Tonight Show, in March 1979, he excoriated incompetent bureaucrats. To keep from descending into straw-man arguments, he typically named names (though not on this occasion): “We hire a man in Washington and pay him public money to do something important, and we see from what he writes on a page that the man is a boob. We’re being cheated somehow.”

He threw many barbs:

“Many college freshmen don’t seem to have any native tongue at all. There is no language in which they can express themselves coherently.”

“I can’t think of a single politician for whom you would vote if you were logical.”

“If we could get control of our language, then we could get control of our minds and know what we think. We’d have opinions that we formed and not that are pressed on us. And we’d get back some dignity as human beings.”

On Mitchell’s second visit to The Tonight Show, in 1979 or 1980 (my re­cording is undated), Carson had been discussing the word eclectic with another word-lover, Tony Randall. Carson had taken the position that eclectic means “selecting the best among various doctrines, methods, or styles.” Randall had argued that the word simply means “composed of elements drawn from various sources.”

Mitchell immediately sided with Randall upon taking his seat.

“Oh, really?” said an incredulous Carson. “Well, the dictionary says that my choice is the first one.”

Mitchell then said something characteristically mystifying: “You know, dictionaries don’t really say what a word means. They say what a certain number of people seem to mean when they use that word. . . . But the word eclectic means I think what [Randall] said it means.” Nodding at Randall, he said, “I’m with you 100 percent.”

Carson then deadpanned, “You want to guest on this show frequently, Mr. Mitchell?” That drew a big laugh.

“Are people still abusing the language?” Carson asked.

Yes, Mitchell said, and in a curious twist he proceeded to blame the Three Mile Island nuclear calamity on an unlikely culprit. “I know who is responsible,” he intoned. “It is the National Council of Teachers of English.” Carson paused amid awkward, scattered laughter.

“Why is that?”

“For 20, 30 years now — maybe 40 — these people, and others like them, have been preaching to us that the things we used to teach, like spelling, punctuation, syntax, verb agreement, are not important — that something more important is the feeling with which we approach things, our creativity. I don’t know exactly what they mean. We’ve taught whole generations of people that small mistakes don’t matter. And when children go to school, they always learn something, but they very seldom learn what we think we’re teaching them. What they learn in this case is exactly that: Small mistakes don’t matter. If you make a little mistake, nothing bad happens. You grow up to be kind of shabby and slipshod.”

Getting back to Three Mile Island, Mitchell went on: “You grow up to be the kind of person who says, ‘Well, that meter doesn’t look right. I turn this faucet, don’t I? Don’t I, Harvey? Maybe to the left, maybe to the right. I don’t know. [Laughter.] When people trained that way go into very technical callings, without this habit of precision, they can kill us.”

“This can be the result,” said Carson.

Sometimes Mitchell seemed to contradict himself. At one point, he ardently defended the importance of learning to spell properly. Moments later, though, he said, “I couldn’t care less about shall and will and who and whom. When human beings talk to each other, they can talk any way they damn please.”

He threw out quite a few of those puzzlers. Interviewers and audiences alike could rarely predict what he might say next. He’d keep ’em guessing.

Mitchell wrote four books that are still worth reading. The first two were the most famous: Less Than Words Can Say (1979) and The Graves of Academe (1981). In the foreword to the former, he analogized critical thinking to staying awake: “Consciousness has degrees. We can be wide awake or sound asleep. We can be anesthetized. He is not fully conscious who can speak lightly of such things as basic appreciations and general insights into the knowledge of a discipline. He wanders in the twilight sleep of knowing where insubstantial words, hazy and disembodied, have fled utterly from things and ideas. . . . We nod, we drowse, we fall asleep. I am trying to stay awake.”

In his later television appearances, he wasn’t sanguine that he was helping very many others to stay awake. The country — even the world beyond our borders — was suffering from a crisis in critical thought. As any thinking person can see, it still is.

Every era needs a Diogenes. In the later part of the 20th century, Richard Mitchell was ours — for those who could stay awake long enough to watch Car­son’s last guest.