In Search of the Holy Grail: How to Reduce the Second Law of Thermodynamics

Citation

Robertson K (2022) In Search of the Holy Grail: How to Reduce the Second Law of Thermodynamics. The British Journal for the Philosophy of Science, 73 (4), pp. 987-1020. https://doi.org/10.1086/714795

Abstract
The search for the statistical mechanical underpinning of thermodynamic irreversibility has so far focussed on the spontaneous approach to equilibrium. But this is the search for the underpinning of what Brown and Uffink have dubbed the ‘minus first law’ of thermodynamics. In contrast, the second law tells us that certain interventions on equilibrium states render the initial state ‘irrecoverable’. In this article, I discuss the unusual nature of processes in thermodynamics, and the type of irreversibility that the second law embodies. I then search for the microscopic underpinning or statistical mechanical ‘reductive basis’ of the second law of thermodynamics by taking a functionalist strategy. First, I outline the functional role of the thermodynamic entropy: for a thermally isolated system, the thermodynamic entropy is constant in quasi-static processes, but increasing in non-quasi-static processes. I then search for the statistical mechanical quantity that plays this role—rather than the role of the traditional ‘holy grail’ as described by Callender. I argue that in statistical mechanics, the Gibbs entropy plays this role.

Keywords
History and Philosophy of Science; Philosophy; History

Journal
The British Journal for the Philosophy of Science: Volume 73, Issue 4