Speaker
Description
This talk raises several issues with standard explanations of time asymmetry, which assume a universally applicable statistical mechanical version of the second law of thermodynamics with a past hypothesis. The theme of criticism concerns the conceptual shifts which take place as thermodynamic entropy is reduced and the resulting definition (I focus on Boltzmann's) migrates between contexts. The most serious difficulties arise when attempting to use the past hypothesis to constrain explicit characterisations of the state of the early universe, while remaining consistent with modern cosmology. In particular, accounting for gravity, dark energy, infinite degrees of freedom, and observed inhomogeneities in the cosmic microwave background are all open problems, with varying prospects for satisfactory solution. I argue that this is enough to motivate considering alternative explanations of time asymmetry, and fortunately, some are available. I outline three options, finally making the case that Gryb and Sloan's ideas involving Janus points and attractors offer the most promising line of research in this area.