could care less, couldn’t care less
Everyone konws that couldn’t care less is the older form of the expression. Eric Partridge in A Dictionary of Catch Phrases (2d ed., 1985) says that the phrase arose around 1940 and was problably prompted by an earlier catch phrase, "I couldn’t agree with you more." If we assume Partridge’s date of origin refers to speech, it is hard to quibble. We do have a 1945 citation from a BBC war correspondent covering a British commando operation:
You would have thought that they were embarking on a Union picnic; they just couldn’t care less - Stewart Macpherson, 24 Mar. 1945, in The Oxford Book of English Talk, ed. James Sunderland, 1953
The OED Supplement and the editor of the second edition of Partridge’s book cite the phase as the title of a book published in 1946.; It was established by the late 1950s and early 1960s in American use:
To me the elaborate framework, and symbolism, was too much for such petty characters. I couldn’t have cared less what happened to any of them - Flannery O’Connor, letter, 17 Jan. 1968
". . . Some place with air condintiong. And without a TV set. I couldn’t care less about baseball." - James Baldwin, Another Country, 1962
The origin of could care less is also obscure. All we know about it for sure is that it came later. Harper 1875, 1985 reports getting letters asking about the expression starting in 1960. That would suggest its existence in speech around that time. No printed examples have so far turned up that antedate the 1966 examples collected by James B. McMillan and cited in his article in American Speech (Fall 1978 ). Our earliest citation is from what appears to be a wire-service picture caption:
This roarless wonder at Chicago’s Brookfield Zoo could care less about the old saying dealing with the advent of March - Springfield (Mass.) Republican, 2 Mar. 1968
The reason why the negative particle was lost without changing the meaning of the phrase has been the subject of much speculation, most of it not very convincing. No one seems to have advanced the simple idea that the rhythm of the phrase may be better for purposes of emphatic sarcasm with could care less, which would have its main stress on care, than with couldn’t care less, where the stress would be more nearly equal on could and care. You, however, may not find this argument very convincing either.
The attitude of the commentators toward could care less has in general been negative. Safire 1980 saw usage of could care less as having peaked in 1973; he dismissed it as defunct in 1980. But it has not disappeared:
The Americans, of course, could care less about British reaction - Joseph White, Springfield (Mass.) Union-News, June 1993
. . . they could care less what anybody outside the team thinks of them - E. M. Swift, Sports Illustrated, 6 Apr. 1987
. . . instead of belonging to an old-line business lobby . . . she is a member of the more militant National Federation of Independent Business. . . . She could care less about the IMF. Her concerns are doing away with estate taxes . . . - Richard Dunham, Business Week, 14 Sept. 1998
Bernstein 1971 thought it not quite established then; if it becomes established, he ways, it will be another example of "reverse English." Pairs of words or phrases that look like opposites but mean the same thing are not unkown in English: ravel/unravel, can but/cannot but, for instance.
This is what our present evidence suggests: while could care less may be superior in speech for purposes of sarasm, it is hard to be obviously sarcastic in print. This may explain why most writers, faced with putting the words on paper, choose the clearer couldn’t care less.
From Merriam Webster’s Concise Dictionary of English Usage
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