“Man’s happiness is twofold … One is proportionate to human nature, a happiness to wit, which man can obtain by means of his natural principles. The other is a happiness surpassing man’s nature, and which man can obtain by the power of God alone, by a kind of participation of the Godhead [ad quam homo sola divina virtute pervenire potest secundum quandam divinitatis participationem], about which it is written (2 P 1:4) that by Christ we are made partakers of the divine nature. And because such happiness surpasses the capacity of human nature, man’s natural principles which enable him to act well according to his capacity, do not suffice to direct man to this same happiness (Thomas Aquinas, Summa Theologica, Response to I-II.62,1).