Comment by Cthulhu_

> Can our sci-fi writers come up with something equivalent that is as dizzyingly far from what we know now, as now is from what Aristocreon knew?

I bet they can, but the danger is that if it's too far away from what we can fathom right now, it's no longer sci-fi but esoterics or something - going from fun to weird. Most science fiction is written in concepts we can understand today.