Summa Theologica

Having considered what belongs to the divine substance, we have now to treat of God's operation. And since one kind of operation is immanent, and another kind of operation proceeds to the exterior effect, we treat first of knowledge and of will (for understanding abides in the intelligent agent, and will is in the one who wills); and afterwards of the power of God, the principle of the divine operation as proceeding to the exterior effect. Now because to understand is a kind of life, after treating of the divine knowledge, we consider truth and falsehood. Further, as everything known is in the knower, and the types of things as existing in the knowledge of God are called ideas, to the consideration of knowledge will be added the treatment of ideas.

Concerning knowledge, there are sixteen points for inquiry:

(1) Whether there is knowledge in God?

(2) Whether God understands Himself?

(3) Whether He comprehends Himself?

(4) Whether His understanding is His substance?

(5) Whether He understands other things besides Himself?

(6) Whether He has a proper knowledge of them?

(7) Whether the knowledge of God is discursive?

(8) Whether the knowledge of God is the cause of things?

(9) Whether God has knowledge of non-existing things?

(10) Whether He has knowledge of evil?

(11) Whether He has knowledge of individual things?

(12) Whether He knows the infinite?

(13) Whether He knows future contingent things?

(14) Whether He knows enunciable things?

(15) Whether the knowledge of God is variable?

(16) Whether God has speculative or practical knowledge of things?