(All of these can be used either by atheists or theists, though almost all of them were integral to the system of a theist philosopher.)
1.) Human beings know only what can be abstracted from matter
God cannot be abstracted from matter.
2.) Human beings must know things intellectually in a general way before they know them distinctly.
Whatever can be known in a general way is not identical with the general way in which it is known
God is identical with any general existence he has.
3.) Human beings know things so far as they can produce a similitude of the known thing within themselves.
Anything produced is created
No created thing can be a similitude of an uncreated one.
4.) He who knows, transcends what he knows
Man can transcend God in no way whatsoever.
5.) He who knows, illuminates the thing he knows and gives it an intelligible existence it would not have without him.
God cannot be given any mode of existence whatsoever.
6.) We can know a creator either as acting by a plan, or not by a plan.
If by a plan, then there is some reality outside of himself, if not by a plan, he is not an intelligence at all.
7.) We can understand a creator only as producing necessarily or contingently.
If by necessity, he is bound, if contingently then he does not explain the contingent existence that arises from him.
But the creator must both act freely and explain the contingent existence that arises from him.
8.) What is known, is known as one thing among potentially many.
God is in no way potentially many.
9.) If creator is intelligible, creation is intelligible.
To understand the creature itself, we have to understand it as either really possible before creation, or not.
But real possibility is real existence, and so there was either real existence of a creature before creation, or the creature is impossible.
But the creature is neither impossible nor really existent before creation.
10.) What acts and what receives are understood as having one action.
In creation, the action is God himself and the existence of the creature is receptive.
But no one action can be both created and uncreated.
11.) In order for a thing to be known by another, that-which-is-knowable about it (usually called “essence”) must be separable from its actual existence.
God’s essence and existence are not separable.
12.) God can be known only if he is known to act on another
Whatever acts, acts from its power to act.
Whatever acts by power has potential existence (sc. to the action)
God is in no way potential.
13.) We can know only what can be properly described by an abstract or concrete term.
But God cannot be properly described by the abstract, since he exists, nor by the concrete since we predicate the abstract of him (I am the life)
14.) We can know only some X when we recognize that it is different to say “X is” and to say “X is X”.
If we understood God, we would see that there is no difference between saying “God is God” and saying “God is”.
15.) If we knew definition of God, we would see he exists.
It is impossible for us to know a definition that provides us information about whether the defined thing exists.
16.) What we can know can be defined.
God cannot be defined.
17.) What can have no positive content to its description cannot be known.
The positive content of a description is given to us only by direct sensation.
18.) Whatever can be known, can be known as “something”.
Whatever can be known as “something” is not necessarily distinct from a creature, for a creature is also known as “something”.
God is necessarily distinct from a creature.
19.) We can know those objects whose knowledge gave some adaptive advantage.
Knowledge of God is does not give an adaptive advantage.
20.) We can understand creation only as the First Cause giving something other than itself the power to exist and act.
Everything other than the First Cause is a sort of instrument and so does not act of itself.
21.) We can know actions only as immanent or transitive
Immanent action never leave the one acting, transitive action presupposes some other on which to act.
But the act of creation both leaves the one acting, and does not presuppose some other on which to act.
22.) We understand only what exists by itself or by another.
If God exists, then a creature is not a substance since it exists only by another.
But I am a substance and am not God.
23.) We know things so far as they act on us, the way light acts on an eye or sound on the ear.
A thing acts on us not as it exists in itself, but as it appears.
God does not appear to us.