We derive a generalization of the Second Law of Thermodynamics that uses Bayesian updates to explicitly incorporate the effects of a measurement of a system at some point in its evolution. By allowing an experimenter’s knowledge to be updated by the measurement process, this formulation resolves a tension between the fact that the entropy of a statistical system can sometimes fluctuate downward...

Skeptics of biological evolution often claim that evolution requires a decrease in entropy, giving rise to a conflict with the second law of thermodynamics. This argument is fallacious because it neglects the large increase in entropy provided by sunlight striking the Earth. A recent article provided a quantitative assessment of the entropies involved and showed explicitly that there is no conf...

The second law of thermodynamics has a curious status. Manymodern physicists regard it as an obsolete relic from a bygone age, while many others, even today, consider it one of the most firmly established and secure achievements of science ever accomplished. From the perspective of the foundations of physics, a particularly interesting question is its relationship with the notion of irreversibi...