On Man's Ultimate End

…[U]ltimate felicity is to be sought in nothing other than an operation of the intellect, since no desire carries on to such sublime heights as the desire to understand the truth. Indeed, all our desires for pleasure, or other things of this sort that are craved by men, can be satisfied with other things, but the aforementioned desire does not rest until it reaches God, the highest point of reference for, and the maker of, things. This is why Wisdom appropriately states: “I dwelt in the highest places, and my throne is in a pillar of a cloud” (Sirach 24:7). And Proverbs (9:3) says that Wisdom “by her maids invites to the tower.” Let those men be ashamed, then, who seek man’s felicity in the most inferior things, when it is so highly situated.

Thomas Aquinas, Summa Contra Gentiles, Book III, Ch. 50, para. 9. tr. Bourke.