“Imagine little Albert asking his physics teacher in 1880: "Sir - for how long do I have to stay at high speed in order to look as grown up as my elder brother?"”

Is that not the other way around? “…how long do I have to stay at high speed in order for my younger brother to look as grown up as myself?”

Staying at high speed is symmetric! You'd both appear to age slower from the other's POV. It's only if one brother turns around and comes back, therefore accelerating, that you get an asymmetry.

Indeed. One of my other thoughts here on the Relativity example was "That sets the bar high given most humans can't figure out special relativity even with all the explainers for Einstein's work".

But I'm so used to AGI being conflated with ASI that it didn't seem worth it compared to the more fundamental errors.

Given rcxdude’s reply it appears I am one of those humans who can’t figure out special relativity (let alone general)

Wrt ‘AGI/ASI’, while they’re not the same, after reading Nick Bostrom (and more recently https://ai-2027.com) I hang towards AGI being a blib on the timeline towards ASI. Who knows.