Science Fiction, its Origins

Hitherto, except in exploration fantasies, the fantastic element was brought in by magic… but by the end of the last century it had become difficult to squeeze even a momentary belief out of magic any longer. It occurred to me that instead of the usual interview with the devil or a magician, an ingenious use of scientific patter might with advantage be substituted… I simply brought the fetish up to date, and made it as near actual theory as possible.

H.G. Wells

Wells claims that he had a notion to paint the old tropes of fantasy with a new, scientific veneer, without substantively changing them, and this sidestep is where science fiction emerged from fantasy. Not an auspicious birth. Feels about right, though; SF always seemed to be a flavor of fantasy.