Gerard Manley Hopkins

Nothing is so beautiful as spring - when weeds, in wheels, shoot long and lovely and lush; Thrush's eggs look little low heavens, and thrush through the echoing timber does so rinse and wring the ear, it strikes like lightning to hear him sing.

The historical novelist has to consider what has actually happened, while the SF writer is dealing in possibilities, but they are both in the business of imagining a world unlike our own and yet connected to it.