[Peanuts, May 3, 1972.]
Sally Brown knows her usage. Alas, she’s replying to the question “Who was the father of Henry IV?”
Garner’s Modern English Usage:
Although some apologists argue that *could care less is meant to be sarcastic and not to be taken literally, a more plausible explanation is that theGarner cites an explanation from linguist Atcheson L. Hench: “Couldn’t care has two dental stops practically together, dnt. This is heard only as d and slurring results. The outcome is I c’d care less.”
-n’t of couldn’t has been garbled in sloppy speech and sloppy writing.
About “some apologists”: Garner is thinking of Steven Pinker, for one, who insists that “I could care less” is not illogical but sarcastic. I hear not sarcasm but dismissiveness: “I couldn’t care less” and “I could care less” are both dismissive, but one makes sense, while the other is, yes, illogical.
But the answer to the teacher’s question is “John of Gaunt.” Or, “John of Gaunt, though I could not possibly care less.”
Related reading
All OCA Peanuts posts (Pinboard)
Linus, nauseated not nauseous : Lucy’s whom : Woodstock’s wormwise
[Yesteryear’s Peanuts is this year’s Peanuts.]