  The older theory had no probabilistic qualifications to its laws. But as Maxwell was clearly aware, it could not then be “exactly” true if the new probabilistic theory correctly described the world. One can either keep the thermodynamic theory in its traditional form and carefully explicate the relationship its principles bear to the newer probabilistic conclusions, or one can, as has been done in deeply interesting ways, generate a new “statistical thermodynamics” that imports into the older theory probabilistic structure.