  This article rebuilds the parity conservation under the light of
Heinsenberg's uncertainty principle and the equivalence among the four
space-time coordinates. The lack of equilibrium between matter and antimatter
is elucidated; neutrino mass is a logical corollary of this asymmetry. Based on
this new concept of parity conservation the existence of black holes is
questioned. It is also found that entropy could decrease in a close quantum
system. CPT would be an exact symmetry if the full Poincare group were the
symmetry group of nature. Therefore, CPT must be violated if nature obeys a
larger symmetry group than that of the full Poincare group. Examples of CPT
violation could be found in a quantum theory of gravity, and the supertheories.
