This is a cool thread, am enjoying reading it, and the links people have presented.
The "steam-engine time" thing was an interesting idea! ...Is it actually a thing, though? Had the Romans actually gone ahead and invented a full-on steam engine, rather than toys merely, then I guess we'd have said that that period was when the steam-engine time was. ...What I'm asking is, has anyone heard of this thing, apart from this guy's take? Is it something that's seriously considered as ...well, true? By sociologists, I suppose?
(But even if it is just one guy's idiosyncratic take, a sci-fi writer's imagination doing its thing, even so it's a very interesting idea, and persuasively enough presented. Enjoyed reading that interview.)
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No one seems to have mentioned agriculture in this thread yet, unless I'm mistaken. I suppose that also would qualify as a discovery, invention, technology, whatever, that happened independently across cultures?