" We still don’t have a clue about what’s going on in the human brain. We have theories; we just don’t know for sure. We can’t build an electrical circuit, digital or analogue or other, that mimics the biological system. We can’t emulate the behavior. One day in the future, we think we can. "

― Annie Jacobsen , The Pentagon's Brain: An Uncensored History of DARPA, America's Top-Secret Military Research Agency