It has been said that, in scale, a human being is about halfway between an atom and a star. Interestingly, this is also the regime in which physics becomes most complicated; on the atomic scale, we have quantum mechanics, on the large scale, relativity. It is in between these two extremes where our lack of understanding of how to combine these theories becomes apparent.
The Oxford scientist Roger Penrose has written convincingly of his belief that whatever it is that we are missing from our understanding of fundamental physics is also missing from our understanding of consciousness. These ideas are important when one considers what have become known as anthropic points of view, best summarized as the belief that the Universe must be the way it is in order to allow us to be here to observe it.
Bang! The Complete History of the Universe, Brian May