One of the most difficult problems for divine simplicity are how to square it with creation and divine knowledge of free actions. On its face, there are at least four distinct states of God:
- God's essential nature
- God's contingent decisions
- God's knowledge of his contingent decisions
- God's knowledge of creatures' free responses to his contingent decisions.
My own preferred sketch of a solution to these problems is here. The solution proceeds by making the contingent aspects of (2)-(4) be extrinsic to God.
For those Christians who are unimpressed by the strength of the traditional commitments (in the pre-Reformation tradition, but also in people like Calvin and Turretin) to divine simplicity, and the arguments for divine simplicity, the natural solution will appear to be to deny divine simplicity, and then not worry about the problem.
They should still worry about the problem. For if one denies divine simplicity and holds that God has at least the two distinct constituents: his essential nature, N, and his contingent decisions, D, then one has to say something about the relationship between these two. Clearly, D is in some way explained by N: God acts as he does in part because of his essentially perfectly good character. The explanation is not a grounding-type explanation—to make it be a grounding-type explanation would be to hold on to a version of a divine simplicity explanation. In creatures, the corresponding explanation of decisions would be causal: the character causes (deterministically or not) the decision. So it seems that we have something very much like a causal relationship between N and D. And this in turn makes D be very much like a creature, indeed perhaps literally a creature. Since D is a constituent of God, it follows that a constituent of God is very much like a creature, perhaps literally a creature. But this surely contradicts transcendence!
Now perhaps one can insist that the relationship between N and D while being akin to causation is sufficiently different from it that D is sufficiently different from a creature that we have no violation of transcendence. Maybe, but I am still worried.
So if I am right, even if one denies divine simplicity, a version of the problem remains. And so the problem may not be a problem specifically for divine simplicity.