Esa-Pekka Salonen

O my God, what must a soul be like when it is in this state! It longs to be all one tongue with which to praise the Lord. It utters a thousand pious follies, in a continuous endeavor to please Him who thus possesses it.

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.