| Further one can nearly always formulate the detailed laws of physics as "variational principles" with integrals over possible states. |
| In the case of high energy physics (QCD or Quantum Chromodynamics theory of fundamental particles), this variational principle is Feynman's path integral. |
| Using Monte Carlo methods for these variational principles leads to a formulation just like statistical physics. |
| Note QCD is a theory of particles moving in 3D space but is formulated as integrals over a four dimensional space time i.e. looks like a 4D statistical problem. |