What proof do you want? We can explain everything in the brain. We know how neurons work, we know how they interact. We even know, where specific parts of “you” are in your brain.

The only thing missing is the exact map. What you are lacking is the concept of emergence. Seriously, look it up. Extremely simple rules can explain extremely sophisticated behavior.

Your stance is somewhere between “thunder go boom! Must be scary man in sky!” And “magnets! Can’t explain how they work!”.