Reasonable. But the thing is... well actually there are two things
If we're, say, carrying five heavy things (that weigh like 10 kg each so it's reasonable to carry more than one per person, but each additional one makes it substantially less pleasant) somewhere and there's two of us, then obviously one of us taking four of the five things and the other taking two is not even possible, and 4+1 or 5+0 aren't very reasonable either, so 2+3 ends up being the convention.
- In math formalized as set theory, 2+3 and 4+1 refer to *the same object*, as defined by the axiom of extensionality. I think this is a similar issue as when people say "one drop of water plus another drop is just one drop not two, math is wrong lol". You've computed something like human_description(merge(water_drop, water_drop)), not water_drop + water_drop. The + operator doesn't do all of your intuitive "and" things, it does something much more narrow. 2 objects in the left hand and 3 in the right aren't any more 2+3 than 4+1... under that extremely formal view.
I am saying that being incorrect ≙ being obviously not useful.
- I don't think saying "5" implies a normative thing. Like, there was another twitter poll that asked,
"Pick the shelling point and also don't pick c" with answers a, b, c, d.
In *that* case, I buy talking about correctness. (
Hilariously, that poll has majority answers on c, ffs.) But if you just say "5", only "5", not even "5.", I don't think you are incorrect to say 4+2 since the poll didn't ask you to choose a number that's 5. You just have an abstract "truth" property.
( This difference between "just writing down an abstract element with a truth value" and "making a claim" really creates a knot in my brain. It's not the first time I've thought about it. )