Versions of Anselm’s ontological argument were later used by both St. Thomas Aquinas and Rene Descartes and were, much later still, heavily criticised by Immanuel Kant.

"Three things are necessary for the salvation of man," wrote Thomas Aquinas, "to know what he ought to believe; to know what he ought to desire; and to know what he ought to do."

It mainly introduces the natural law thoughts of Aquinas, Hobbes and lays the foundation for the Renaissance of the new natural law thoughts of Rawls.