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by kccqzy 1150 days ago
Once you get to infinities, you can no longer denote the "size" of a set using naturals numbers, which is the typical usage of the word "size" (there are three apples in my basket and three is a natural number).

So to me this is just quibbling about the definition of the word "size" which isn't a productive conversation. Stop calling it "size" and give it a specific terminology ("cardinality") instead and the whole unintuitive naming problem is sidestepped.

1 comments

You can even give in a little more without accepting the blatant takeover of "bigger": accept that there are different qualities in infinite comparisons. A difference in cardinality can certainly be considered a stronger difference than everything mappable, but denying infinites like "number of points on an infinite line" it's smaller-than relative to "number of points on two infinite lines" is just ridiculous. It's snobbish, pure vanity.
My point is that intuitive but imprecise naming misleads people. There's no way to talk about "number of points on an infinite line" because there isn't a specific natural number that you can find to denote the number of points here. Infinity is not a number.

That's why we need a proper concept of cardinality.