Could care less? That must mean there's some level of care I still possess about linguistics. "I have some care about linguistics." I'm not even sure that makes sense. "I could care less what he said." I have some care about what he said. They aren't the same. If I really did have some care about what he said, I'd probably say, "I care a bit (little/lot- or 'sort of care') about what he said,"
It seems this is a pet peeve for a lot of people. Does the literal interpretation make sense? Not really. It's an idiom. Idiom's make no literal sense. Kicking the bucket. Needle in a haystack. A piece of cake. Sure, these CAN have literal meanings (speaking of, cake sounds good right now), but generally the mean something different.
Even if you were to say it's not idiomatic, I still think it's a valid phrase. It could be used in a sarcastic/ironic way (This site and this site each try and deduce the origins of the phrase, citing similarities to Yiddish phrases, comparing it to phrases like, "I should be so lucky!" or "Tell me about it!"). I tend to believe it could be a shortened version of, "I *COULD* care less, but I care so little that it doesn't really matter."
Not everyone agrees with the ironic view, however: This site in particular. It is the origin (possibly?) of the image above with the caring continuum. Paul Brian suggests that "People who misuse this phrase are just being careless.." He explains more in this interview (
As I was browsing he web for references, and to develop my opinion on this, I came across this writing tips article. It basically uses the view that it's idiomatic. The comments are interesting, though. One person uses similar reasoning that the phrase is a shortened version of "I suppose I could care less, but I don’t see how." There's some argument as to what actually sense and what doesn't. There's also the view that "[u]sing 'could care less' demonstrates a lack of basic understanding of the semantics of English language."
There are a few comments that do irk me, namely these two:
"The English language is quite complicated, and has to be made simple so those with a lower IQ can learn enough of it to get by. This simplifed English is known as American English."
"You are corrupting language, helping it evolve into a form which makes less sense than it does now. If anybody wants to complain that English is a complicated language to learn and has no discernible rules, ... it’s because it has a long history of people bastardising it like this." (in turn, this person links to this article which states, "Our civilization is decadent, and our language--so the argument runs--must inevitably share in the general collapse," implying "the decline of a language.")
I generally dislike this attitude. Languages change. This includes grammar, pronunciation, idioms, metaphors, etc. It all changes. There are lots of reasons for change. Is laziness one? I wouldn't call it "laziness" per se, but I would agree that if there's an easier way to say something, that way will likely become part of a language. Why work harder when you don't have to? Things change because their use changes. As long as a person's message can be understood by others, that will likely stick... at least in some part (a regional thing, or even just between a small group).