  This paper aims to justify the use of statistical mechanics tools in
situations where the system is out of equilibrium and jammed. Specifically, we
derive a Boltzmann equation for a jammed granular system and show that the
Boltzmann's analysis can be used to produce a ``Second Law'', $\dot{S}\ge 0$
for jammed systems. We highlight the fundamental questions in this area of
physics and point to the key quantities in characterising a packing of
particles, accessible through a novel experimentation method which we also
present here.
