Right, but imagination starts from what is known, so Vera Historia has wars, journeys, whales and gods. A whirlwind takes them to the moon, and so on. But it would have been very hard for them to imagine the direction that _technology_ would go. That writing (scrolls and ink) could expand into something like the internet and smartphones. They could have imagined long range telepathy I suppose, which is perhaps in the right ballpark. "Any sufficiently advanced technology is indistinguishable from magic"

And speaking of Arthur C Clarke - in the mid 1960s he could extrapolate from current technology and imagine something a bit like the internet, but conceived of it as a news service, a bit like teletext (see the novelisation of '2001'). The paradigm shift where anyone can publish and you get things like wikipedia, social media and git was a conceptual leap that was very hard to make in advance.

What I'm asking is, despite the huge volume of sci-fi we can produce, could there be something two thousand years from now that is practically unimaginable to us?