Experience proved that man's power of choice in action was very far from absolute, and logic seemed to require that every choice should have some predetermining cause which decided the will to act. Science affirmed that choice was not free,— could not be free,— without abandoning the unity of force and the foundation of law. Society insisted that its choice must be left free, whatever became of science or unity. Saint Thomas was required to illustrate the theory of liberum arbitrium by choosing a path through these difficulies, where path there was obviously none.

Mont Saint Michel and Chartres (1904)