I could care less
Matthew Martin 4/06/2016 07:17:00 AM
First of all, "less" is a word that requires a comparison of two or more things. If I say "This cup has less juice in it," without context there's absolutely no way to know what I meant. Probably the most common interpretation would be that there exists at least one other related cup containing more juice in them than the one that I singled out—as in, "this cup has less juice in it than those cups." But I could also have meant, for example, "this cup has less juice in it than is required by these specifications." When using comparison words like "less" and "more" we often leave the necessary comparison clause unspoken because it can usually be easily inferred by context.
Which brings us back to the expression "I could care less." What are we comparing to? People who argue that "I couldn't care less" is the only correct formulation make an implicit but unnecessary assumption that the comparison clause is always "than I currently do," as in "I couldn't care less than I currently do." But the comparison could just as easily be "than anyone else." If we take the latter as the comparison clause, it's the "couldn't" that is incorrect: "I couldn't care less than anyone else" specifically rules out the possibility that another person exists who cares less than you.
But the other thing we need to bear in mind is that "could" is a statement about probabilities and not exclusively reserved for counterfactuals. People who argue that "I could care less" is incorrect assume that the expression implies that you do not currently care less when in fact it specifically includes this as a possibility. That is, "I do care less" is a subset contained within the range of possibilities implied by "I could care less." To give a similar example, "I could be faster than you" means that at the present moment, me being faster than you is a real possibility—it would be unreasonable to interpret that statement as saying that I am definitely not currently faster than you.
The fact is that both idioms, "I could care less" and "I couldn't care less" are equally correct. They differ in what they compare your current amount of caring to. If the comparison is to other people, then "could" is correct, whereas if the comparison is to your own current state of caring, then "couldn't" is correct.
But then, you really didn't need that spelled out for you, did you? Because you already knew exactly what is meant by "I could care less."