(CG 3/49). That the Knowledge which Pure Spirits have of God through knowin... (Book 3. God, the End of Creatures) (Summa Contra Gentiles) (Aquinas, Thomas, St.)

EVERYTHING that is imperfect in any species desires to gain the perfection of that species. He who has an opinion about a thing, opinion being an imperfect knowledge of the thing, is thereby egged on to desire a scientific knowledge of the thing. But the aforesaid knowledge, which pure spirits have of God without knowing His substance fully, is an imperfect kind of knowledge. The main point in the knowledge of anything is to know precisely what it essentially is. Therefore this knowledge which pure spirits have of God does not set their natural desire to rest, but rather urges it on to see the divine substance.

2. The knowledge of effects kindles the desire of knowing the cause: this search after causes set men upon philosophising. Therefore the desire of knowing, naturally implanted in all intelligent beings, does not rest unless, after finding out the substances of things made, they come also [etiam, not etiamsi] to know the cause on which those substances depend. By the fact then of pure spirits knowing that God is the cause of all the substances which they see, the natural desire in them does not rest unless they come also to see the substance of God Himself.

4. Nothing finite can set to rest the desire of intelligence. Given any finite thing, intelligence always sets to work to apprehend something beyond it. But the height and power of every created substance is finite. Therefore the intelligence of a created spirit rests not in the knowledge of any created substances, however excellent, but tends still further in a natural desire to understand that substance which is of infinite height and excellence, namely, the divine substance (Chap. XLIII).

6. The nearer a thing is to the goal, the greater is its desire. But the intelligences of pure spirits are nearer to the knowledge of God than is our intelligence: therefore they desire that knowledge more intensely than we do. But even we, however much we know that God exists and has the attributes above mentioned, have not our desire assuaged, but still further desire to know God in His essence: much more then do pure spirits. The conclusion is, that the final happiness of pure spirits is not in that knowledge of God whereby they know Him through knowing their own substances, but their desire leads them further to the substance of God.

Hereby it sufficiently appears that final happiness is to be sought in no other source than in activity of intellect, since no desire carries so high as the desire of understanding truth. All our other desires, be they of pleasure or of anything else desirable by man, may rest in other objects; but the aforesaid desire rests not until it arrives at God, on whom all creation hinges and who made it all. Hence Wisdom aptly says: I dwell in the heights of heaven, and my throne is in the pillar of a cloud (Ecclus xxiv, 7) ; and it is said, Wisdom calls her handmaids to the citadel (Prov. ix, 3). Let them blush therefore who seek in basest things the happiness of man so highly placed.