Martin Barrett

Is Entropy Relevant to the Asymmetry Between Retrodiction and Prediction

The idea that the changing entropy of a system is relevant to explaining why we know more about the systems past than about its future has been criticized on several fronts. This paper assesses the criticisms and clarifies the epistemology of the inference problem. It deploys a Markov process model to investigate the relationship between entropy and temporally asymmetric inference.

The Second Law of Probability Dynamics

When the probability of causes, and the probability of effects, given causes, are each randomly assigned, entropy ‘usually’ increases.

The Possibility of Infinitesimal Chances

Are chance zero events possible? David Lewis thought not. He and others have proposed replacing zero chances by nonzero but infinitesimal chances in order that such events might be constructed as possible. I examine the details of a number of models aiming to accomplish this and conclude that they don’t work, ending with a pessimistic assessment of the prospects for this program.

The form of magnetic work in a fundamental thermodynamic equation for a paramagnet

Magnetic work takes two forms in the thermodynamics of a paramagnet as developed in many textbooks. We observe that in the case when the lattice energy is excluded, the form δW=BdM cannot be used in a fundamental thermodynamic equation. This shows that there are thermodynamic systems with no fundamental thermodynamic equation.