My rationalization about that effect was around the idea that the deeper is your knowledge on a topic, the more aware you become of how much is left to know. Tu

My rationalization about that effect was around the idea that the deeper is your knowledge on a topic, the more aware you become of how much is left to know. Turning what you don't know that you don't know into something that you know that you don't know. Not being aware of things that you don't know gives you confidence.