>What else would a flight of fancy be other than imagining something that we currently have absolutely zero evidence for? Exactly, but that was spirit of OP's

>What else would a flight of fancy be other than imagining something that we currently have absolutely zero evidence for? Exactly, but that was spirit of OP's question. I do think that the fact that we can rewind our own history and find examples of technologies that were unimaginable at some more distant point in our history as something more than "absolutely no evidence."