When we write what we don’t know, we launch ourselves into terra incognita. That’s where the good stuff is.

Well, yes! Terra incognita: that's the territory of the imagination, where fresh new ideas are formed by the mating of "what if" and story, is it not?

Writing only what you know - as the time-honoured advice to new writers would have it - leads inexorably to a career in journalism. And I don't know about you, but that's not a rabbit hole I want to go down.