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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'', 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.