Abstract
Is Reality digital or analog? After a short historical introduction to the answers given to this old question, we argue that Nature is neither completely digital nor analog but a wise mixture of both. We show, using the canonical theory, that many macroscopic processes studied in physics, chemistry, and biology could not happen in a purely analog Universe, because these processes are the outcome of trillions and trillions of elementary processes directly related to the microscopic structure of matter. Next, we show that the "exotic" processes observed at the nanoscale, and needed for a fundamental understanding of the basic mechanisms of life and for the development of the nanotechnology, could not exist in an analog Universe. Some examples are the recently discovered "exotic" flows of heat from cold to hot regions or the tiny difference in the pressures of a gas and a nanogas at mechanical equilibrium. We present a fundamental concept of time and show how the more conventional concept of dimensional time associated to the spacetime arises from several approximations. The current emphasis by many physicists on that spacetime would be quantized and that its discretization would introduce a fundamental understanding of causality and other aspects of Nature at the Planck scale does not hold up on close inspection. The limitations and deficiencies of theories as general relativity and quantum field theory, inherited by further developments as quantum general relativity and superstring theory, are highlighted; with the conclusion of that no discrete spacetime can reproduce the mathematics and physics associated to our fundamental concept of time. The relation of our approach with the SHP theory and its use on recent generalizations of superstring and brane theories are noted. Other foundational questions asked in this "FQXi ESSAY CONTEST" are answered in a final section.
Juan R. González-Álvarez