A number of you out there in Readerland are writers, and I thought I might share a notion which came to me along with a new plot idea.
There is a long-standing piece of advice given to writers which states: write what you know. I would like to make a rebuttal.
Of the various writings I have produced, very few have been a case of ‘writing what I know’. Indeed, the vast majority have been on subject matter I very much do not know. This approach has benefits for both the casual-storyteller writer and the nitpicky-fact-checker writer.
For instance, a casual storyteller writing what he or she doesn’t know does not have to have his or her creativity constrained by what is and therefore can perhaps better imagine what could be or could have been. A fact checker, on the other hand, will not be relying on any preconceived notions regarding what they think they know and can be sure of turning in a well-researched manuscript.
I won’t deny that writing what you know has been an excellent tool for some authors; nobody would dispute that Khaled Hosseini is writing what he knows, and doing it extremely well. However, I would also be willing to bet that Yann Martel has never been adrift on a boat with only a 500-pound tiger for company – and Life Of Pi is nevertheless a remarkable work of fiction. Similarly, some of the best science fiction and fantasy writing has come from imaginations so far-fetched as to defy any notion of writing what one knows.
Having said all that, there is one area in which writing what one knows is sound advice for all, and that is character development and interaction; unless one is writing robots, aliens, vampires or other non-humans, a thorough understanding of human nature is essential to a well-rounded character.
So here’s my tip for the writers out there. Pick something that interests you, but which you know very little about it, and make it the centerpiece of a new story. I think you’ll find it a worthwhile exercise.
That Other Blog, Way Over There 
I think it’s more like, “Write what you know emotionally.”
You can research what sort of engine an F150 has. You can look up who the 14th president of the US was. You can remember what that quick stab of fear feels like when someone surprises you. You can apply it to a different situation—but if you’ve never felt that feeling, the only way to write it down is to borrow the words from others, quite often in the form of cliches.
@uninvoked
I see what you’re saying there, but I think that still suggests that someone who has led a comparatively sheltered life would be incapable of creating great literature; personally, I think that “write what you can imagine” is perhaps a better notion than “write what you know”.