A second way of stating the entropy law is in terms of statistical thermodynamics. It is recognized today that not only are all scientific laws empirical but also that they are statistical. A great number of individual molecules, in a gas for example, may behave in such a way that the over-all aspects of that gas produce predictable patterns in the aggregate, even though individual molecules may deviate from the norm. Laws describing such behavior must be formulated statistically, or probabilistically, rather than strictly dynamically. The dynamical laws then can theoretically be deduced as limiting cases of the probabilistic statements.

Popescu, who won a Dirac Medal last year for his insights in quantum information theory and quantum foundations, said he and his collaborators work by “pushing quantum mechanics into a corner,” gathering at a blackboard and reasoning their way to a new insight after which it’s easy to derive the associated equations. Some realizations are in the process of crystalizing. In one of several phone conversations in March, Popescu discussed a new thought experiment that illustrates a distinction between information and other conserved quantities — and indicates how symmetries in nature might set them apart.