Statistical mechanics owes much more to Ludwig Boltzmann than is usually believed. In his attempts to derived thermodynamic and transport phenomena from deeper microphysical assumptions, he explored at least five different approaches: One based on mechanical analogies (with periodic mechanical systems or with statistical ensembles), one based on Maxwell's collision formula, one based on the ergodic hypothesis, one based on combinatorial probabilities, and one based on the existence of thermodynamic equilibrium. I will sketch this various approaches and show how Boltzmann judged them and interconnected them. It will also argue that in general Boltzmann was more concerned with constructive efficiency than with precise conceptual foundations. Basic questions on the reality of atoms or on the nature of probabilities played only a secondary role in his theoretical enterprise.
Philosophy of Physics Seminar Convenors for TT19: James Read and Simon Saunders