St. Thomas Aquinas presents salvation history in three stages: The Age of Nature, the Age of Law, and the Age of Grace. The pagans are stuck within the age of nature; fallen humanity inevitably declines into idolatry and slavery. But, God has a plan for saving man. From the time of Moses until...

The pagan cosmos is a closed world: the city is never truly self-sufficient, requiring natural slaves and war; regimes rise and fall cyclically; the regime's justice is never true justice. In the Treatise on Law (ST I-II, Q.90-108), St. Thomas Aquinas presents a different vision: the open world...