So many circular arguments. The Pythagorean theorem tells you that √2 exists, but not that it’s irrational. As for the story, it’s apocryphal, not ahistorical,

So many circular arguments. The Pythagorean theorem tells you that √2 exists, but not that it’s irrational. As for the story, it’s apocryphal, not ahistorical, but even so, it was too good of a story not to tell my students when I taught Math for Liberal Arts Majors (the version I’d heard was that the proof was presented while the Pythagoreans were on a boat and they were so offended by the idea that √2 is irrational, they threw the guy off the boat. I would guess that of all the things I said in lectures for that class, this is the one that my students would be most likely to remember).