Thomas Aquinas

“ According to this opinion God would have the idea of the first created thing alone; whereas, if the order itself of the universe was created by Him immediately, and intended by Him, He must have the idea of the order of the universe. Now there cannot be an idea of any whole, unless particular ideas are had of those parts of which the whole is made; just as a builder cannot conceive the idea of a house unless he has the idea of each of its parts. So, then, it must needs be that in the divine mind there are the proper ideas of all things. ”

“ God is the similitude of all things according to His essence; therefore an idea in God is identical with His essence.
Art. 2 - Whether ideas are many? Objection 1: It seems that ideas are not many. For an idea in God is His essence. But God's essence is one only. Therefore there is only one idea.
Objection 2: Further, as the idea is the principle of knowing and operating, so are art and wisdom. But in God there are not several arts or wisdoms. Therefore in Him there is no plurality of ideas. ”

“ Further, an idea is considered to be the principle of knowledge and action. But the divine essence is a sufficient principle of knowing and effecting all things. It is not therefore necessary to suppose ideas. ”

“ God has no practical knowledge, except virtually, of things which neither are, nor will be, nor have been. Hence, with respect to these there is no idea in God in so far as idea signifies an "exemplar" but only in so far as it denotes a "type."
Reply to Objection 3: Plato is said by some to have considered matter as not created; and therefore he postulated not an idea of matter but a concause with matter. Since, however, we hold matter to be created by God, though not apart from form, matter has its idea in God ”

“ Further, if it be said that ideas are multiplied according to their relations to different creatures, it may be argued on the contrary that the plurality of ideas is eternal. If, then, ideas are many, but creatures temporal, then the temporal must be the cause of the eternal. ”