Sam Walton

The market is incredibly inefficient and capable on rare occasions of being utterly dysfunctional. And people have a really hard time getting their brain around that fact. They want to believe that it's approximately efficient almost all the time, and it simply isn't true.

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.