Note: This is the third in a series of articles on Divine Simplicity. The first can be found here: 15 Arguments for Divine Simplicity. The second can be found here: Biblical Arguments for Divine Simplicity.
In this last article on the topic of Divine Simplicity, we will be correcting some misunderstanding that James White has expressed on this topic. The central error is one of definition. The way in which White has defined the Thomistic view of Divine simplicity is that we affirm that the attributes of God are synonymous, i.e., that there is no distinction made between them.
He has describes this variously, “the claim that God’s wrath is God’s mercy, or that God’s justice is God’s omniscience, etc.”  He goes on to say that it comes from a metaphysic (which he, ironically, claims is “Medieval”) that posits that “if you can distinguish things in the mind, they are separable in reality.”  b.n., any student of medieval theology will rightly realize that this claim is laughable, for, there is a difference between a rational and real distinction per St. Thomas himself.
Further, he goes on to express the same explanation, “As Aquinas evidently takes this…you cannot discuss the attributes of God in a way that would make them different to one another because that then implies parts which denies the simplicity of God. So, God’s omniscience is His omnipresence and His imminence.” 
These quotes suffice, each time, over the past months, he has described the Thomistic view of Divine simplicity in the same way. He labels such with the boogeyman term “Absolute Divine Simplicity.” Even after being corrected time and time again, by many Thomists (myself included), he has continued with this shameful strawman.
This article seeks, not to convince of the position, but to clarify what the Thomistic (including Reformed) tradition actually is saying on this matter. I pray that James White will stop this misrepresentation and realize, if he truly affirms what he says he does, that St. Thomas’ view is reconcilable with his own on the matter.
In sum, St. Thomas does not teach that God’s attributes are each other. The attributes of God are our intellectual conceptions of His being as is related to created perfections and the effects of His operations. The attributes are His being, but they are not each other. As Thomas summarizes, “although names predicated of God signify the same thing, they are not synonymous, because they do not convey the same meaning.”
To understand this, we must understand the doctrine of the naming of the attributes in St. Thomas and to the Catholic tradition (For a helpful article see: How to speak about God). In brief, we name the various attributes of God based on created effects of His operations and created perfections which participate in the Divine perfections. Thus, the Thomist rightly insists that the attributes are not synonymous, because they reveal something different about the Simple Divinity through different created effects.
Our intellects, not capable of understanding simplicity in a positive manner, name based on those created perfections in which they present to us. The attributes are really the perfection of God flowing to creation, and we understand and reason from effect to cause in pieces. It is because attributes are understood through the medium of our finite intellect that diversifying happens.
This is clear throughout St. Thomas writings, and I will quote liberally.
First, from Prima Pars, Q. 13, A. 4. In the sed contra, he proves that the names of God are not synonymous because, “All synonyms united with each other are redundant.” This, ironically, is the exact issue that James White takes with the Thomistic view.
In the respondeo, he argues from the nature of Divine naming. For,
“the idea signified by the name is the conception in the intellect of the thing signified by the name. But our intellect, since it knows God from creatures, in order to understand God, forms conceptions proportional to the perfections flowing from God to creatures, which perfections pre-exist in God unitedly and simply, whereas in creatures they are received and divided and multiplied. As therefore, to the different perfections of creatures, there corresponds one simple principle represented by different perfections of creatures in a various and manifold manner, so also to the various and multiplied conceptions of our intellect, there corresponds one altogether simple principle, according to these conceptions, imperfectly understood. Therefore although the names applied to God signify one thing, still because they signify that under many and different aspects, they are not synonymous.”
In the responses to the objections he clarifies his view on the matter. To the first, the reason for the diversification is because our “term[s] only signif[y] the thing through the medium of the intellectual conception.”
To the second objection, our terms for God “corresponds to…one simple reality represented by them in a manifold and imperfect manner.” Again, this is not due to any imperfection in God, but because of our finitude, the attributes come to us “in a manifold and imperfect manner” whereas in God they are one.
In his response to the third objection, he provides the most succinct presentation of his view on the manner,
“the perfect unity of God requires that what are manifold and divided in others should exist in Him simply and unitedly. Thus it comes about that He is one in reality, and yet multiple in idea, because our intellect apprehends Him in a manifold manner, as things represent Him.”