"Your brain waves are the not caused by thoughts, they ARE your thoughts." How can you know that? How do you know that your mind isn't somewhere else (in some

"Your brain waves are the not caused by thoughts, they ARE your thoughts." How can you know that? How do you know that your mind isn't somewhere else (in some sense of "where"), and transmitting signals to your brain, which simply acts as a receiver? I don't say this is true, I'm just asking how you would empirically or experimentally distinguish that situation from the notion that your brain makes up your thoughts.