Christopher Morley

For poets today or in any age, the choice is not between freedom on the one hand and abstruse French forms on the other. The choice is between the nullity and vanity of our first efforts, and the developing of a sense of idiom, form, structure, metre, rhythm, line - all the fundamental characteristics of this verbal art.

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.