That's the equivalent of saying that a painter shouldn't sketch or doodle. That he/she will just "know" when the subject is right and start painting the right p

That's the equivalent of saying that a painter shouldn't sketch or doodle. That he/she will just "know" when the subject is right and start painting the right picture. I humbly disagree. Not saying you should -pursue- every idea you have, but there's little harm in taking notes. In fact, I'd argue it's more beneficial than not. Take notes. Read them. Edit them. Add to them. Throw some away. Ignore others. But your idea list is your sketch pad, and sketching is good exercise for the mind. And maybe you'll find yourself sketching the same thing over and over. And you'll keep coming back to that one theme. And THEN, you've got something...