Tim Challies lists three “chief concerns with open theism”:

1. A Denial of Omniscience. While men like Greg Boyd deny that open theism denies God’s omniscience, this is simply not true. Even if it is true that the future exists only as possibilities, something that is not adequately proven by open theists, we are still putting a limit on God’s knowledge when we state that He cannot know these possibilities. This view of God’s knowledge of the future is unique in that it is at odds with every other Judeo-Christian tradition.

Denial of omniscience is a false claim. Tim Challies falls for the fallacy of equivocation. He predefines Omniscience to mean his own definition, which mirrors Platonistic “active knowledge”. He ignores historical worldwide definitions of omniscience. He ignores just about every Open Theist being on record as believing in Omniscience. Tim Challies is being intellectually dishonest with this claim.

2. God’s goodness, greatness and glory are at stake. The God of the Open Theists is, in the words of Bruce Ware, too small. He is not the all-knowing, all-powerful God revealed so clearly in the pages of the Bible. Christians need to always be concerned that both they and God are making poor decisions based on inadequate information. Thus we cannot always count on God to do what is best, because even He does not always know what this is.

If God is depicted as “all-knowing” in the Bible (by which Tim Challies means that God has active, innate knowledge that originates in Himself and extends over all space and time) then the debate probably would never have surfaced. But Tim Challies’ weird Platonistic omniscience is not found anywhere in the Bible, nor are general claims of exhaustive knowledge of all the future.

Challies then relies on the moralistic fallacy to criticize Open Theism. He does not use intellectual generosity when he says Open Theism believes God makes “poor decisions based on inadequate information”. This is all ignoring the wide Biblical literature in which God repents, regrets past decisions, accepts input of prayer to change His plans, and otherwise engages in activities that Challies would label as “poor decisions”.

3. The Christian’s confidence in God is at stake. If open theism is true, the Christian cannot put his full trust and confidence in God. “The God of open theism will always want our best, but since he may not in fact know what is best, it becomes impossible to give him our unreserved and unquestioning trust” (Bruce Ware, Their God is Too Small, page 20. When hardships arise we will have to ask if God anticipated these, or if He is as shocked and distressed as we are.

Again, Challies relies on the moralistic fallacy. Challies’ idea is that he can form the perfect god in his own head, and that god will conform to reality. This is not a serious claim.

Furthermore, as will all moralistic fallacies, the knife cuts both ways. Maybe people will reject a stone, static, unchanging, and Platonically omniscient god as being evil, weak, and altogether meaningless. Far from being able to trust this static god, Ware’s claim (and by extension, Challies’ claim) is that all sorts of evil is God’s plan for maximum ultimate glory. What trust do we have in a God that hurts all sorts of people, without any volition, in order to glorify Himself. We trust this “god” to save us? Why? He has already shown that hurting people glorifies him. As the originator and father of all lies, the Calvinist god could easily just be lying to everyone.