Maxwell’s demon can violate the second law of thermodynamics on a molecular level—it can add information to a system and lower its entropy. In principle it could do so in a way that affects the shuffling of a deck of cards.

Laplace’s demon, on the other hand, knows the precise location and momentum of every particle only because it’s extrapolating from knowing their precise locations and momenta at a previous point in time and then applying deterministic physical laws. But the intervention of Maxwell’s demon violates those laws, potentially adding a growing degree of uncertainty to Laplace’s predictions.