My definition of an expert is someone who can say, "Yeah, I've made that mistake before." And follow up with, "And this is how I fixed it."

I learn by doing. I can't learn by reading. I learn my mistakes. Trial and error. Or, if the stakes are higher, I learn by rile and terror.

I learn by teaching. Not so much learning new, but learning refinements. Thanks to the reach of the internet, I have some younger siblings that I try to teach, but not (usually) in a push-down way.

Usually, I discuss my choice, my reasonings and my logic. Then, my sib is free to examine mine, share hirs, challenge, debate, discuss. And if s/he doesn't, I usually ask.

From this, I can learn more about my sib, about different ways of thinking. Different reasonings, different weightings for factors. Different conclusions.

For me, the goal of teaching is not "this is what you must think," but simply, "this is what you must: think."

[Yes, it's short, it's backdated. You caught me. ;) ]