JP: Why does science fiction matter?
GW: I think it matters a lot, because it’s mind-opening. That’s its great virtue. Ordinary fantasy opens minds, but not nearly as much. The Oz books [1900–1920] may open someone’s mind a little bit. Alice in Wonderland  is kind of mind-opening. But a lot of science fiction is much more so. For instance, I could write a story in which a man has a conversation with his gun. I might do that sometime. Prince Valiant had his singing sword, and I always thought they could have done more with that than they did.
JP: Many people say that science fiction matters because it is about contemporary society—that it is a kind of satire.
GW: Unfortunately. It’s true that a great many people think that it must be.
JP: You mean: it needn’t be so.
GW: You could write a book about a landing on Mars in which a landing on Mars is a metaphor for something that is going on now. You could also write a book about a landing on Mars that’s a landing on Mars.
— Excerpt from an interview with Gene Wolfe. (Thanks Matt!)