Spin-Statistics connection and the gravity of the Universe: The Cosmic   connection
  I suggest that the Spin-Statistics connection is a consequence of the phase shifts on quantum scattering amplitudes due to the induced gravitomagnetic field of the whole Universe at critical density. This connection was recently brought out in the context of a new theory of relativity in flat space with matter, called Cosmic Relativity (gr-qc/0406023). This prediction of the correct gravitational phases is a consequence of any relativistic gravitation theory in the presence of the massive Universe. This can also be interpreted as related to the Mach's principle applied to quantum phenomena. Perhaps this is the simplest valid proof of the Spin-Statistics Theorem, and it finally identifies the physical origin of the connection. 
C. S. Unnikrishnan (Tata Institute, Mumbai)