  In this article, the rotational invariance of entangled quantum states is
investigated as a possible cause of the Pauli exclusion principle. First, it is
shown that a certain class of rotationally invariant states can only occur in
pairs. This will be referred to as the coupling principle. This in turn
suggests a natural classification of quantum systems into those containing
coupled states and those that do not. Surprisingly, it would seem that
Fermi-Dirac statistics follows as a consequence of this coupling while the
Bose-Einstein follows by breaking it. Finally, the experimental evidence to
justify the above classification will be discussed. Pacs: 3.65.Bz, 5.30 d,
12.40.Ee
