MIXED reactions greeted the news in February that a man had edited thousands of Wikipedia articles with a single, special passion. His mission? To remove every instance he could of the phrase “comprised of”. Bryan Henderson is convinced by a traditional rule about how “comprise” can be used: “The parts compose the whole, and the whole comprises the parts.” Mr Henderson has made more than 47,000 such changes. Medium.com calls him “the ultimate WikiGnome”. The nickname might imply condescension, but Medium’s profile makes clear that many people applaud him. Mr Henderson is not alone in an all-consuming linguistic passion. Bradvines, a commenter on Lingua Franca, the language blog of the Chronicle of Higher Education, surfaced last week in the comments on an article by Geoff Pullum, a syntactician at the University of Edinburgh. Mr Pullum was writing about whether “a certain closeness” was grammatical. (It is.) But Bradvines ignored the subject at hand. He instead insisted that “had developed” was ungrammatical, as in “he had developed a certain closeness.”

This diverted a dozen or so confused commenters into engaging Bradvines. What on earth is wrong with “He had developed”? Bradvines insisted that “had” could never go before a “past-tense verb”, and “developed” is a past-tense verb; therefore “had developed” is not permissible. He was unmoved by repeated statements that this is the classic past perfect (or pluperfect) in English and is perfectly grammatical.

Someone with the Amazon name Brad Johnston, who seems to be the same person, has reviewed 259 books on Amazon. Nearly all of them are grammar or usage guides. Nearly all of them get one star from Mr Johnston. Nearly all the reviews mention the same fatal flaw: past-perfect forms like “had done” and “had said”. Grammar books by Mr Pullum himself, by Bryan Garner (a lawyer and respected usage-book writer), by Grammar Girl (a popular and admirable grammar populariser) all get the same rap. Mr Johnston even taunts Cambridge University Press for publishing Lindley Murray’s “English Grammar”. “If the author of this text was born in America, I would be very much interested to hear his/her defense of 'had had', except in the subjunctive. That's an open invitation. Fire away.” Murray died in 1826.

Besides his hundreds of reviews, he has denounced the English past perfect across other websites, and Mr Pullum says that he has been e-mailing him for years. In other words, he appears to be a classic monomaniac. Numbers mean nothing to him: just because literally hundreds of grammar books say it is doesn’t make it so. (One of his few Amazon reviews of something other than a book is of set of colourful plastic pails and shovels for children: "I needed the shovel for a very specialized scooping task." This raises the small but distinct possibility that Mr Johnston is a sophisticated performance artist.)

What does this have to do with Mr Henderson, who has edited “comprised of” out of tens of thousands of Wikipedia entries? Many readers see an immediate distinction: Mr Henderson may a bit quixotic, but he is fighting a good fight. Mr Johnston has picked an unwinnable fight with countless authorities on English grammar.

But the difference between the two men is one of degree, not of kind. Mr Johnston is not convinced by hundreds of usage books, but Mr Henderson is not convinced by tens of thousands of Wikipedia entries. Of course just because something is common doesn’t make it standard English. Some errors are common among inexpert writers but are still clearly errors—things like their for they’re. But Wikipedia editors are largely people like Mr Henderson: educated native speakers of English who volunteer their time to spread knowledge. Could 47,000 such people all be wrong?

Consider also that “is comprised of” has been on a steady rise in English books since 1920, and is now about a fifth as common as “is composed of”. A list of writers whom Mr Henderson would correct includes Charles Dickens, Herman Melville, Christopher Hitchens, Lionel Trilling and Alfred North Whitehead. “Comprised of” appears 1,880 times in the United States Code (the main body of American federal statutes). “Fixing” this problem would require Congress to sit day and night for weeks.

The hopeless quest against the past perfect and the hapless quest against “comprised of” show that correctness may better be considered a spectrum than a black-and-white affair. A rule's place on that spectrum is essentially determined by the number of people—and especially the number of experienced writers and editors—who observe it. On one end of the spectrum are rules virtually every speaker of English can agree on: the standard third-person singular of to have is has, for example. On the other end are rules that almost no one would endorse: Mr Johnston may well be the only person in the world who thinks that had developed is ungrammatical.

In the middle are countless disputed rules: if “comprised of” is a stark line, it is an odd one. It divides Mr Henderson, his admirers and sympathetic grammarians (who include Bryan Garner) from Hitchens, Melville and 47,000 Wikipedians. A “rule” like that hardly deserves the designation of a “rule”—but our black-and-white thinking about language has not given us a more accurate way to describe it.