Paul Theroux

I have never pretended to be the best Scientologist, but I openly and vigorously defended the church whenever it was criticized, as I railed against the kind of intolerance that I believed was directed against it. I had my disagreements, but I dealt with them internally.

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.