 From this analysis it is clear that the description of our universe at very small (and very large) scales involves mathematical models that are alien to our experience of reality in everyday life. The properties that allow us to understand the world (the existence of stable, discrete objects that preserve their identity in space and time) seem to be emergent aspects of a much more complex reality that is incomprehensible to us outside its mathematical formulation. Yet, at a macroscopic level, the universe facilitates elementary processes, like counting, measuring lengths, and the manipulation of symbols, that allow us to develop a consistent hierarchy of mathematical models some of which seems to describe the deeper underlying structure of reality. 