It didn’t take long for the comments to roll in about the title of yesterday’s post, “I’m disinterested, and I could care less.” The commenters had little to say about disinterested, but they were keen to reproach me for using the erroneous and illogical could care less.

Thus they fell into the trap, giving me matter for another post.

Insufferable prig as I was in my long-ago youth — and well into what passes for maturity — I was never bothered by people who said, “I could care less.” I always knew that they meant that they couldn’t care less and that the two expressions were functionally interchangeable.

The Language Loggers have expended some energy on this topic, with Mark Liberman posting three times in 2004, July 8, July 13 and July 16. These posts are worth a look, because they largely demolish the objections.

Steven Pinker, writing in The Language Instinct, suggests that could care less was originally, and remains, ironic or sarcastic, communicating disdain. I suspect that there is a good deal to that, though Professor Liberman differs with Professor Pinker on that point. Something similar appears to be going on in the citations in Professor Liberman’s post about a similar pattern with scatological or obscene content : “I could give a [insert the expletive or chain of expletives of your choice].

What is indisputable, I think, is that whatever the origin, could care less is a stock expression, an idiomatic one. No native speaker misunderstands it. It is one of many phrases in English that do not mean what they literally say.

People object that it is illogical. There’s a misunderstanding there. Language has patterns that linguists and grammarians can describe, but they are not necessarily logical ones. Languages that assign gender to all nouns, for example, do so arbitrarily; there is no logical reason that a table should be feminine in French. In English, spelling is notoriously irregular. Logic, especially reasoning by analogy, is one of the things that gives us folk etymology.

English is a messy language, amalgating elements from Anglo-Saxon, Norman French and Latin. And since its origins, it has been relentlessly promiscuous, picking up vocabulary from street corners the world over.

No, if you are looking for logic in a language, I suggest that you have a go at Esperanto. It’s a shame if could care less abrades your delicate sensibilities, since there appears to be nothing to be done to relieve the irritation.