It's not what you think...

You can't always believe your brain because sometimes your brain fools even itself! Because your first instinct is to believe what you see and hear, you can easily be fooled into doing and thinking things that otherwise would seem ridiculous. This is where science comes in- think about what you see and hear and compare that to what you know to be true. If both pieces of input seem to agree, they are probably correct. If not, you probably need a new theory- for example if you know that a man can't float in a sitting position, the next scientific step is to make a theory of how this seemingly impossible thing is happening and then test that theory against what you know. Of course its always fun too, to just go with it and be amazed!