"If pigs could fly" chemistry: a tutorial on the principle of microscopic reversibility.

Through a glass darkly: Several recent autocatalytic reaction models for the origin of homochirality have suggested ways in which one enantiomer of the product might be reconverted into the other by a recycling reaction in a closed system. These models are revealed to violate the principle of microscopic reversibility, a powerful tool for assessing the plausibility of proposed reaction networks even at far-from-equilibrium conditions.