Friday, February 4, 2011

Pruss' Argument against Open Theism

  1. (Premise) If p is overwhelmingly probable on the balance of God's evidence, then God believes p.
  2. (Premise) If open theism is true, then some of the propositions that are overwhelmingly probable on the balance of God's evidence are false.
  3. Therefore, if open theism is true, God believes some falsehoods.
  4. (Premise) God believes no falsehoods.
  5. Therefore, open theism is false.
Alex Pruss here constructs what I think is a promising argument against open theism. Essentially, (1) assumes the typical open theist assertion that God acts with respect to probabilities; he knows creatures so well he does not have to know the future in order to know what they will probably do. Indeed, (1) seems wholly reasonable, as there is no discernible reason why God would refrain from believing a proposition if it were overwhelmingly probable to be true.

Perhaps one would object that since future contingents do not have truth values, (1) is false and God believes nothing about these overwhelmingly probable propositions. But doesn’t that seem strange? For instance, God knows the probability of p relative to background knowledge of the situation at hand; why think that God nonetheless believes nothing about the future? Some other reason is needed besides a desire to avoid the argument’s conclusion! If one wishes to object that God would only believe it is probably true, he is committing a category error. The category of the object of belief is ontological; God thinks “probably, P is true,” rather than “P is probably true.” There are no degrees of truth with respect to individual referents.

What about (2)? This seems to be easily shown. Pruss argues from the potentially-infinite future of free actions (or the seemingly limitless number of free actions that occur in our world under the open theist model) to show that it is virtually certain some of these beliefs (of which free choices are made causally independently of one another) will be false (after all, the probability is some lesser-bound than 1). (3), then, is just true analytically.

The only hope for the open theist, then, is to deny (4). This would be “biting the bullet” and just admitting God holds some false beliefs. But in this case, God would be less than perfect. Perfection is a trait most open theists wish to retain.[1] Some premise must be denied, and I suppose the best candidate will be (1). But this would contradict the open theist assertion that God operates on probabilities. If God operates on neither probabilities nor knowledge, what does he operate on?
                [1] For instance, many open theists claim God is omniscient since future contingents have no truth-value (meaning there is still nothing to know that is unknown to God). This argument doesn’t object to that; it merely points out God will more plausibly than not hold beliefs which are overwhelmingly probable to be true. By the sheer number of free actions, some of these will be false.


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