Is the eternal law the highest conception [or plan] existing in God?

It seems that the eternal law is not the highest conception [or plan] (ratio summa) existing in God:

Objection 1:  The eternal law is a single law only.  But there are many conceptions (rationes) in God’s mind, since in 83 Quaestiones Augustine says, “God made individual things by means of conceptions that are proper to each of them.”  Therefore, the eternal law does not seem to be the same as a conception existing in God’s mind.

Objection 2:  As was explained above (q. 90, a. 4), it is part of the nature of law that it be promulgated by a spoken word.  But as was established in the First Part (ST 1, q. 34, a. 1), ‘Word’ is predicated of a person in God, whereas ‘conception’ is predicated of the divine essence.  Therefore, the eternal law is not the same as God’s conception.

Objection 3:  In De Vera Religione Augustine says, “It is clear that above our mind there is a law, which is called truth.”  But the law that exists above our mind is the eternal law.  Therefore, the eternal law is truth.  But the nature of truth is not the same as the nature of a conception.  Therefore, the eternal law is not the same as the highest conception.

But contrary to this:  In De Libero Arbitrio 1 Augustine says, “The eternal law is the highest conception, which must always be conformed to.”

I respond:  Just as a conception (ratio) of the things made through his craft exists beforehand in a craftsman’s mind, so too in anyone who governs there must exist beforehand a conception of the ordering of the things to be done by those who are subject to the governor’s rule.  And just as the conception of the things to be made through a craft is called an artistic conception (ars) or exemplar (exemplar) of the artifacts, so too the conception had by one who governs the acts of his subjects takes on the character of law, given the presence of all the other elements we described above (q. 90) as belonging to the nature of law.
Now as was established in the First Part (ST 1, q. 14, a. 8), it is through His wisdom that God is the creator of the totality of things, and He is related to those things in the way a craftsman is related to his artifacts.  As was likewise established in the First Part (ST 1, q. 22, a. 2 and q. 103, a. 5), God is also the governor of all the acts and motions found in each creature.  Hence, just as the divine wisdom’s conception has the character of an artistic conception or exemplar because all things are created through it, so too the divine wisdom’s conception has the character of law insofar as it moves all things to their appropriate ends.  Accordingly, the eternal law is nothing other than the divine wisdom’s conception insofar as it directs all acts and movements.

Reply to objection 1:  Augustine is speaking here about the ideal conceptions (rationes ideales) that relate to the proper natures of singular things, and so, as was established in the First Part (ST 1, q. 15, a. 2), among these conceptions there is distinction and plurality corresponding to their diverse relations to the things.
However, as was explained above (q. 90, a. 2), law directs acts in relation to the common good.  But things that are diverse in themselves are counted as one insofar as that they are ordered to something common.  And this is why there is a single eternal law, which is the conception of this ordering.

Reply to objection 2:  There are two things that can be considered with respect to any word, viz., (a) the word itself and (b) what is expressed by the word.  For a spoken word is a certain sound emanating from a man’s mouth, and this word expresses the things that are signified by human words.  The same holds for a man’s mental word, which is none other than something which is conceived by the mind and by which a man mentally expresses the things he is thinking about.
In God, then, the Word, which is the conception of the Father’s intellect, is predicated of a person, but, as is clear from Augustine in De Trinitate 15, this Word expresses each thing that is contained in the Father’s knowledge—regardless of whether it has to do with the divine persons, the divine essence, or even the works of God.  And among the other things expressed by this Word, the eternal law itself is also expressed by this Word.  Nor does it follow from this that ‘eternal law’ is predicated of a person in God.  However, it is appropriated to the Son because of consonance between a conception and a word (see ST 1, q. 39, a. 7-8 ).

Reply to objection 3:  God’s intellectual conception is related to things in a way different from the way in which the human intellect’s conception is.
For human understanding is measured by the things, so that a man’s conception is not true by virtue of itself, but is instead called ‘true’ by virtue of the fact that it fits (consonat) the things.  For a belief (opinio) is true or false by virtue of the fact that the thing is or is not such‑and‑such.
By contrast, God’s understanding is the measure of the things, since, as was explained in the First Part (ST 1, q. 16, a. 1), each thing is true insofar as it is like (imitatur) God’s understanding [of it].  And so God’s understanding is true by virtue of itself, and thus His conception is truth itself.