Karl Popper and Thermodynamics Zombies (Professors of Physical Chemistry)
February 23 2006 at 8:57 AM
L. McGlashan, Chemical thermodynamics, Academic Press, London (1979), pp. 72-73:
"For an infinitesimal change in the state of a phase alpha we write
dU = T dS - p dV + SUM mu_B dn_B (1)
We regard equation (1) as an axiom and call it the fundamental equation for a change of the state of a phase alpha. It is one half of the second law of thermodynamics. We do not ask where it comes from. Indeed we do not admit the existence of any more fundamental relations from which it might have been derived. Nor shall we here enquire into the history of its formulation, though that is a subject of great interest to the historian of science. It is a starting point ; it must be learnt by heart. It may be allowed to stand as an axiom until any single one of the host of equations that can be derived from it (with the help of other axioms of thermodynamics) has been shown experimentally to be false."