We open our eyes and we think we're seeing the whole world out there. But what has become clear—and really just in the last few centuries—is that when you look at the electro-magnetic spectrum we are seeing less than 1/10 Billionth of the information that's riding on there. So we call that visible light. But everything else passing through our bodies is completely invisible to us. Even though we accept the reality that's presented to us, we're really only seeing a little window of what's happening.
If you cannot always elicit a straight answer from the unconscious brain, how can you access its knowledge? Sometimes the trick is merely to probe what your gut is telling you. So the next time a friend laments that she cannot decide between two options, tell her the easiest way to solve her problem: flip a coin. She should specify which option belongs to heads and which to tails, and then let the coin fly. The important part is to assess her gut feeling after the coin lands. If she feels a subtle sense of relief at being "told" what to do by the coin, that's the right choice for her.
This is the hallmark of a robust biological system: political parties can perish in a tragic accident and the society will still run, sometimes with little more than a hiccup to the system. It may be that for every strange clinical case in which brain damage leads to a bizarre change in behavior or perception, there are hundreds of cases in which parts of the brain are damaged with no detectable clinical sign.