only what He knew. He knew only what He witnessed of the forms of known things as they are in themselves—what changes of them and what does not change. He witnesses them all in their state of nonexistence, in the varieties of their changes without end, and brings them into existence only as they are in themselves.
From here you learn God's knowledge of things: their nonexistent and existent, their necessary, possible, and impossible. According to what we have established, there is no Book that precedes except by relating the Book to that through which the thing appears in existence, according to what the Real witnessed of it in its state of nonexistence. This is truly the Book's precedence.
The Book preceded that thing's existence. The tasting of this is known by one who knows engendered things before their engendering: they are witnessed by him in their state of nonexistence, while they have no existence.
Whoever possesses this knows the meaning of the Book's precedence. He should therefore not fear the Book's precedence over him, but only fear himself. For neither the Book nor knowledge preceded concerning him except according to what he was upon, of the form in which he appeared in his existence.
Blame yourself, then; do not object to the Book.
(The Conclusive Proof and the Servant's Return to Himself)
From here, if you understand, the Real described Himself as possessing the conclusive proof should He be disputed. It is impossible for knowledge to attach to anything except what the known thing is upon in itself.
If someone argued against God, saying to Him, ‘Your knowledge previously established concerning me that I would be thus; why, then, do You call me to account?’ the Real would say to him, ‘Did I know you except according to what you are upon?
If you had been otherwise,
