Yes, when I say “I could care less”, I usually drop my pants and start beating my meat, then walk around on my knuckles.
That is exactly what I was trying to get at with pi equalling 3 but I like your version far more.
I don’t doubt it.
Heh. I just wanted to express my appreciation of this. (It’s the nature of message boards to put targets on backs even when none is merited, I suppose.)
Calling someone a “pedant” as retaliation for a statement of preference for SE is something I can’t much respect. To each his own, I suppose. But for every cry of “pedant” there’s someone not owning his own defensiveness.*
*or her own defensiveness, as the case may be.
Is that the same as “I doubt it”? It might be, because English is such a rich and evolving language! 
You continue to miss the point. Have you examples of people saying “I don’t doubt it” and meaning “I doubt it”? Then no, no it might not be.
Okay, now that is sarcasm.
What is NOT sarcasm: “I could care less about X.”
The phrase is not, as claimed elsewhere in this thread (e.g. in post #75) an “inversion” of “I couldn’t care less about X.”
The actual sarcastic inversion of “I couldn’t care less about X” would be “I am overwhelmed, consumed, and possessed by X!” or “X is the center of my world!” or “nothing matters but X!” or any phrase that (sarcastically) asserts that the speaker does indeed care about X.
Any claims that “I could care less” constitutes an “evolution” or “sarcastic variant” or “inversion” of “I couldn’t care less,” are plainly ex post facto attempts to sidestep the embarrassment of having been caught out.
(I say that as someone who is regularly caught out misusing “different from” and/or “different than.” I have a mental block about this; no matter what mnemonics I use, I never can remember which is SE and which is despised. All I can ever recall is that “different to” is British (which doesn’t help). So I’m not claiming, here, to be an exemplar of language mastery. I’m just saying: making stuff up to ‘explain’ lapses isn’t particularly respectable.)
Person A: “I could jump to the moon.”
Person B: “I don’t doubt it.”
Their is now. Usage! I love it.
Note the smiley: you know perfectly well what I meant when I said, “I don’t doubt it.” Just as you would know what I meant if I said, “I could care less about your lame attempt to bolster prescriptivism.”
In both cases, I’ve successfully communicated an idea to you. THAT IS WHAT LANGUAGE DOES. Note that I just, “incorrectly,” used capital letters in the middle of a bunch of words; again, by doing so, I communicated something to you successfully. That is what a good communicator does.
The objection to “I could care less” is totally spurious: people suggest that, although
- Everyone knows what the phrase means; and
- It’s an idiom that’s widely used; and
- It can be interpreted sarcastically,
nevertheless it is an example of poor communication.
No. It’s an example of poor computer programming, if you’re programming a computer that doesn’t understand idioms. It’s a fine example of communication.
If it’s so plain, then I’m sure you won’t mind writing something up and submitting it to Linguistics or another journal and save the Zwickys and Libermans of the world from having to waste any more time studying it, thanks dear.
Not that I think it will do any good, but you do realize you haven’t demonstrated anything here except that you continue to not grasp the concept?
People care more about “I could care less” than I could possibly have imagined! 
Pinker also has this to say in his discussion of this phrase;
Possibly many people who use the idiom today have little idea of its development, but if panache45 (no relation) is correct, this has not always been the case.
If anyone is making a mistake, it is the people who think this emerged as a mistake; and possibly people who use it nowadays, without a full appreciation of its rich history. But there are lots of idioms that have lost their original punch nowadays.
Still, isn’t a bit odd that one phrase and its exact logical opposite are both used by people to mean the exact same thing?
What you (and Exapno and several others in this thread) are insisting is that, if a significant number of people use word or phrase X to mean Y, it thereby follows that X does mean Y. Even if X is a phrase that, interpreted literally on a word-by-word basis, means nothing of the sort, it can still be an idiom that means Y. Is that a fair statement of your position?
I, at least, concede this point. However, there are other things being discussed here.
One of those other things is the origin of the phrase “I could care less.” When we’re looking at the question of what the first person, or first few people, were thinking when they used the phrase, its generally understood meaning nowadays is irrelevant. One of the things people have been discussing in this thread is whether those first person(s) to use the phrase did so deliberately, or as a mistake (which came to take on a life of its own). I don’t think it’s obvious what the answer to that question is, and people have contributed arguments either way.
Another thing is that, even if substantial numbers of people use X to mean Y, many other people may be bothered by such usage, for various reasons, including that it reduces the precision and/or logical coherence of language. Maybe such opinions don’t really belong in a General Questions thread, but I don’t think it’s unreasonable to have or express them.
I haven’t seen any coherent arguments that support the idea that ‘could care less’ was a mistake, just assumptions; whereas Pinker’s analysis of the stress and intonation seems to show that it is spoken in a distinctly different way from the (slightly) older phrase, so it is not a mishearing.
At least this was the case in 1994, when he made the analysis; the intonation itself might have evolved since then.
No, I am not missing the point. You are. That was my effort at delightful sarcasm 
and a perfect analogy with the subject of the OP.
Bye that logik, this sentense iz a fine eggzample uv comunikashun, to. Shirley you know wat im saing. I iz a grate comunikator!
I could give a damn.
They can go speak ithkuil, lojban, esperanto or one of the many other conlangs invented to kill the ambiguity inherent in any natural language and their whining will be just as hilarious when those languages develop ambiguities all their own.
The only difference and it’s a critical one is that there’s a body of evidence demonstrating that the former is recognized as having that meaning. No one, and I include you and Rittersport in this actually believes “I don’t doubt it,” can mean “I doubt it,” and therefore, it doesn’t. I recommend you go read the book Frindle.
Could you be taking this any more personally?
I suspect that the answer is ‘no.’ You couldn’t.
Yes, that’s a parallel construction to ‘X couldn’t care less’…and not to ‘X could care less.’
Whatever helps you sleep at night.
I suppose the bottom line is that some proportion of those who use “could care less” will greatly resent being told that it’s non-standard. And of that number, some proportion will declare that they are using it intentionally, because it’s (fill in the blank) sarcastic or an evolution or what the cool kids are saying.
That’s fine. But these people need to realize that they have no right, as such, to have their usage (or their explanation) accepted by all. They can say what they like, but they can’t command acceptance–much less admiration.
In life, none of us can reasonably expect admiration for everything we do. Those who chose to go on saying “could care less” will simply have to accept that some listeners will form a negative view of their level of literacy…even if they couldn’t care less about that negative view or those who hold it.