The faculty of remembering — of retaining and recalling what one has already experienced — helps us to act in the present and plan for the future. This is why St Thomas Aquinas associates memory with the virtue of prudence, the first of the four cardinal virtues, which comprise of prudence, justice, fortitude and temperance. Prudence aids us in perfecting all other virtues and is the closest of all the cardinal virtues to the theological virtues of faith, hope and charity, because it helps us to choose the best means of attaining our goal, and to order everything to our final end. Its rule is reason informed by faith, by the examples and teaching of Jesus Christ and His true imitators, the saints.
Just as aptitude for prudence is in our nature, while its perfection comes through practice or grace, so too, as Cicero says in his Rhetoric, memory not only arises from nature, but is also aided by art and diligence.St Thomas Aquinas, Summa Theologica, 2a 2ae, Q. 49. A1 g