The free will of God

[LeonardDeNoblac]

Everyone who is familiar with Thomism knows about the doctrine of Divine Simplicity - that is, the attributes and operations of God (intellect, will, power, goodness, ecc. ) are not really distinct from His essence and from each other.
However, given Divine Simplicity, it follows that the will of God is the same thing as His essence; and, because God’s essence can’t be different from what it is (God is by nature a necessary being, so He can’t be different from what He is ), it seems that God can’t will anything different from what He wills.
I know that Saint Thomas Aquinas answers that the things willed by God are not absolutely necessary, but only from supposition - that is, supposed that God wills something to exist, it is impossible for that thing not to exist.
This answer succeeds to explain why Divine Simplicity doesn’t lead to a modal collapse (that is, creation becomes necessary, wich implies determinism ), as some of the critics of the doctrine suggest, because it mantains that creatures are by nature contingent.
Still, there’s the problem of why God wills what He wills. Some people (like the Blessed John Duns Scotus ) try to explain away this problem by applying voluntarism (that is, we will what we will for no other reason than our will itself ) to God. However, applying voluntarism to God seems to introduce contingency in Him, wich would make His will a brute fact without any explanation.
Is there any known solution to this problem? Or should we simply give in and accept that the will of God is a mystery (wich doesn’t mean that it is without any explanation, but simply that it has an explanation that we don’t know and perhaps will never know ), ineffable as God Himself is?

 

[Vico]

… Is there any known solution to this problem?..

Summa Theologiae > First Part > Question 19. The will of God > Article 3. Whether whatever God wills He wills necessarily?

I answer that, There are two ways in which a thing is said to be necessary, namely, absolutely, and by supposition. … Hence, since the goodness of God is perfect, and can exist without other things inasmuch as no perfection can accrue to Him from them, it follows that His willing things apart from Himself is not absolutely necessary. Yet it can be necessary by supposition, for supposing that He wills a thing, then He is unable not to will it, as His will cannot change.

Summa Theologiae > First Part > Question 19. The will of God > Article 5. Whether any cause can be assigned to the divine will?

I answer that, In no wise has the will of God a cause. … Now as God by one act understands all things in His essence, so by one act He wills all things in His goodness. Hence, as in God to understand the cause is not the cause of His understanding the effect, for He understands the effect in the cause, so, in Him, to will an end is not the cause of His willing the means, yet He wills the ordering of the means to the end. Therefore, He wills this to be as means to that; but does not will this on account of that.

 

[LeonardDeNoblac]

I mentioned Aquinas’ solution of the first part of the problem in my original post. The second part, however, still remains.