This is where formal mathematical (and programming) logic diverge from natural language. You are right to say that (mostly) "Everyone doesn't X" will (probably) be understood.
I, however, have 20 years experience in trying to teach mathematical logic and proof, and for those who use that style of expression there seem to be additional hurdles to overcome. They don't "get" why the logical converse of "For all X, Y" isn't "For all X, not Y". It's hard work convincing some of them, because it doesn't correspond to the language they use.
Similarly, in natural language people from different locations on occasion fail to understand each other.
I'm not trying to say that what one person says is right or wrong, I'm trying to point out the potential for misunderstanding, and the natural language analysis that corresponds to formal logic. Personally, I regard logic and proof as one of the intellectual highlights of human endeavor. The fact that natural language sometimes doesn't work that way needs to be understood.
That was (one of) my point(s).
I offer for consideration the difficulties that these issues create for natural language processing. If someone says "Everyone doesn't dance" - what exactly do they mean?
I understand the point you're making, and don't disagree that the literal meaning of the phrase is inconsistent with what people typically mean by it (much like "I could care less").
I offer for consideration the difficulties that these issues create for natural language processing. If someone says "Everyone doesn't dance" - what exactly do they mean?
If you want accurate reconstruction of the intended meaning, rather than wanting to constrain natural language to having a single meaning for each statement, then you'll need both contextual and general knowledge to figure out a meaning. I would say that it's clear that someone saying "Everyone doesn't dance", assuming that that was all that was said, meant "Not everyone dances", since it's rather obvious that some people do dance. If, however, they'd said "Everyone doesn't want to die", it would no longer be clear, since it's possible for people to believe that literally no one wants to die (with appropriate excuses made for suicides and posthumous heros). But I don't think that rules of English will be able to tell you anything more about the case than that it could be meant either way; outside information will have to guide the parsed meaning.
I, however, have 20 years experience in trying to teach mathematical logic and proof, and for those who use that style of expression there seem to be additional hurdles to overcome. They don't "get" why the logical converse of "For all X, Y" isn't "For all X, not Y". It's hard work convincing some of them, because it doesn't correspond to the language they use.
Similarly, in natural language people from different locations on occasion fail to understand each other.
I'm not trying to say that what one person says is right or wrong, I'm trying to point out the potential for misunderstanding, and the natural language analysis that corresponds to formal logic. Personally, I regard logic and proof as one of the intellectual highlights of human endeavor. The fact that natural language sometimes doesn't work that way needs to be understood.
That was (one of) my point(s).
I offer for consideration the difficulties that these issues create for natural language processing. If someone says "Everyone doesn't dance" - what exactly do they mean?