Physical concepts are free creations of the human mind, and are not, how ever it may seem, uniquely determined by the external world. In our endeavor to understand reality we are somewhat like a man trying to understand the mechanism of a closed watch. He sees the face and the moving hands, even hears its ticking, but he has no way of opening the case. If he is ingenious he may form some picture of a mechanism which could be responsible for all the things he observes, but he may never be quite sure his picture is the only one which could explain his observations. He will never be able to compare his picture with the real mechanism and he cannot even imagine the possibility of the meaning of such a comparison.Albert Einstein, 1938
So, if you understand that, I will buy you all the beer in the world.
Jonathan, thank you for the introduction to the books of Richard P. Feynman. I will definately be re-reading them.
