What You Know

"Write what you know" suggests you already have starting material for saying something. As you begin to write what you know, hopefully you also begin to see what you don't know. So you do some research, re-evaluate what you know, and re-commence with your writing.

The inverse is true, too. What you know is revealed in what you write. That starting material shows what you thought you knew. The number of books languishing in my Did Not Finish pile typically have something in common: the material was rife with unexamined beliefs that I will not spend time and energy on. I'd rather make mistakes to fix than continue to live in error.