Algorithmic Information Content, Church — Turing Thesis, Physical Entropy, and Maxwell’s Demon

Measurements convert alternative possibilities of its potential outcomes into the definiteness of the “record” — data describing the actual outcome. The resulting decrease of statistical entropy has been, since the inception of Maxwell’s demon, regarded as a threat to the second law of thermodynamics. For, when the statistical entropy is employed as the measure of the useful work which can be extracted from the system, its decrease by the information gathering actions of the observer would lead one to believe that, at least from the observer’s viewpoint, the second law can be violated.