[xamuel]

Yes, it's instructive to recall that the Pythagorean Cult believed all numbers were rational (and this was a religious sort of belief). There's a legend (albeit probably not historically accurate) that when a member of the cult proved that sqrt(2) was irrational, they put him to death... https://en.wikipedia.org/wiki/Hippasus

[pfdietz]

I wonder how they would have reacted to a proof that the reals are a larger infinity.