Clark’s solution is to distinguish human responsibility from God’s causative agency. This is certainly a helpful solution which the Reformed world should utilize, yet I do not see it as solving the question completely. (from my review of The Presbyterian Philosopher: The Authorized Biography of Gordon H. Clark, here)
Chalcedonian theism marks the high point of orthodoxy with regards to the doctrine of God. This catholic (small "c") tradition defines God as one being/ essence, three persons, and this one God has one will and one nature in His being. Jesus Christ, the second person of the Trinity, is one person with two natures (human and divine), and thus two wills. In traditional theism, a nature has a will, and thus Christ's two natures necessitates the existence of two wills. One could also extrapolate that to mean Christ has two minds, as indicative of the fact of Him having two wills.
What, then, is nature? What is will? What is person? Such questions should not be difficult to answer, especially when one looks at the Greek words behind these concepts: nature (φυσις), will (θελημα), person (προσωπον). "Nature" is an ontological terms defining what a thing is. "Will" originates decisions and actions. "Person" is more complicated and much confusion reigned over the term, but in association with the term hypostasis (ὑποστασις), a "person" is a subsistence, an instantiation. To simplify things, I would use the term "individuated consciousness." Note here that I did not say "individual consciousness," or "individuated center of consciousness," in order to keep the definition generic, since the three persons of the Trinity are one and the same being.
A "nature" is what a thing is. A "will" originates decisions and actions. What a thing is is separate from what a thing decides. Socrates is a man; that is his nature. Socrates ate his dinner; that is his will originating a decision to eat, and his body obeying his will to eat. Such is basic English and basic philosophy 101. A "nature" is never a "will," and, as we can see in recent times, it is possible for people to will something (transgender surgery) contrary to their nature (humans as inherently male and female).
God has His own nature, which is who He is ad intra. God wills, and acts accordingly, ad extra. Whatever God wills has its origin ad intra, but is manifested ad extra, where it then effect His works. There should be no question whatsoever that God's nature and God's will is distinct. To be sure, God is consistent, as God is one and simple. Therefore, according to traditional theism, God's will should be consistent with God's nature.
Since we never know God's nature simpliciter, in the history of theology, we come across the debate between realism and voluntarism, in the debate over the potentia Dei absoluta et ordinata (power of God absolute and ordained). Is the power of God absolute, in the sense that He can will anything including alternate past events, round squares and evil as good (divine voluntarism). Is it the power of God restricted to what He ordained to come to pass, and thus is not "absolute" in that sense (realism). Radical divine voluntarism, as held to by the nominalists, have God's power extending over contingency (possible past events), logical contradictions (round squares) and moral contradictions (evil as good). The orthodox position would deny the latter two (at least in their crude form) since they make no sense, but debate remain over contingency. As an example, can God create a world where He can forgive sins without the atonement of Christ? Those who hold to voluntarism might answer yes, while the realists would definitely say no.
So what does this obscure medieval debate has to do with Gordon Clark's theodicy? This "obscure" debate is relevant only because it brings up the same issues concerning God's nature and God's will. It must be noted that we are not talking about whether Clark's solution to the problem of theodicy is helpful. We are speaking concerning those who think that Clark's solution to the problem of theodicy is THE solution. Those who think that appeal to a fiat declaration that God is by definition good and therefore the entire question of theodicy is solved have not begun to scratch the surface of the problems it creates within the doctrine of God. In Clark's solution, we have the following propositions:
(1) God (by definition) is good
(2) God wills evil things
(3) God is ex lex (outside the law) and thus cannot be judged by His law.
Conclusion: Therefore, God is good even though He wills evil
As ONE solution, it is helpful. But we note here there are two propositions concerning the doctrine of God that we need to take note also:
(4) God is one and simple, therefore His will and His nature within Him are one and the same.
(5) God's law is a reflection of His nature
Putting propositions 1-5 together will create a problem, which shows that theodicy is not as easily solved just by Clark's solution. For, yes, God is ex lex in the sense that God is not culpable of evil just because He wills evil. But what is the law? What does willing evil say about the nature of God? For since God is one and God is simple, then His will (as originating ad intra) is equivalent to His nature, but if His will is His nature, then does willing evil things mean that God's nature is evil? But then it is protested that God by definition is good? Well then, you have a contradiction between proposition 1 and 4, and merely repeating proposition 1 does not solve the contradiction you will have. Unless of course, you do not mind throwing away the doctrine of divine simplicity. The same problem will arise when we ask how we can square propositions 3 and 5.
The radical followers of Clark will just assert propositions 1-3 over and over again, and either ignore or deny propositions 4 and 5. Such an emphasis on the divine will as dissociated from the divine nature is a characteristic of divine voluntarism. To be sure, they do not affirm clear logical or moral contradictions, but their emphasis on the divine will blind them to the problems such voluntarism have concerning one's doctrine of God. Perhaps they wish to deny propositions 4 and/or 5? But for those of us who do not reduce everything to "will" alone, we can affirm Clark's solution solve the moral aspect of theodicy, but acknowledge it leaves untouched the ontological problem of theodicy. (For those wanting to know how to solve that latter problem, a pointer would be to distinguish God's will concerning evil as primarily good, while secondarily evil.)