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#138 Divine Sovereignty and Quantum Indeterminism

December 07, 2009

Dear Dr Craig,

I just have a question concerning quantum mechanics, God's foreknowledge and God's foreordination.

Given that quantum events are genuinely indeterminate, do you think it is possible for God to know the outcome of these events without controlling them? And is it possible for God to not only know, but also to foreordain, the outcome of certain quantum events without controlling them? And if so, how?

Any help on this issue would be great!

Thanks a lot,


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Dr. craig’s response


Great question, Lucy! The answer is: Yes, via His middle knowledge! Let me explain.

Christian theologians have traditionally affirmed that in virtue of His omniscience God possesses hypothetical knowledge of conditional future contingent events. He knows in advance, for example, what would have happened if He spared the Canaanites from destruction, what Napoleon would have done had he won the Battle of Waterloo, how your neighbor would respond if you were to share the Gospel with him.

Hypothetical knowledge is knowledge of what philosophers call counterfactual conditionals, or simply counterfactuals. Counterfactuals are conditional statements in the subjunctive mood. For example: "If I were rich, I would buy a Mercedes;" "If Goldwater had been elected President, he would have won the Vietnam War;" "If you were to ask her, she would say yes." Counterfactuals are so called because the antecedent and/or consequent clauses are typically contrary to fact: I am not rich; Goldwater was not elected President; the U.S. did not win the Vietnam War. But sometimes the antecedent and/or consequent clauses are true. For example, my buddy, emboldened by my assurance that "If you were you ask her, she would say yes," does ask the girl of his dreams for a date and she does say yes.

Christian theologians have traditionally affirmed that God does, indeed, have knowledge of true counterfactuals and, hence, of the conditional future contingent events they describe. What theologians disputed, however, was, so to speak, when God has such hypothetical knowledge. The question here doesn’t have to do with the moment of time at which God acquired His hypothetical knowledge. For whether God is timeless or everlasting throughout time, as an omniscient being He must know every truth there is and so can never exist in a state of ignorance. Rather the "when" refers to the point in the logical order concerning God's creative decree at which God has hypothetical knowledge.

Post-Reformation theologians argued about the logical placement of God's hypothetical knowledge. Everybody agreed that logically prior to God's decree to create a world, God has knowledge of all necessary truths, including all the possible worlds He might create. This was called God's natural knowledge. It gives Him knowledge of what could be. Moreover, everyone agreed that logically subsequent to His decree to create a particular world, God knows all the contingent truths about the actual world, including its past, present, and future. This was called God's free knowledge. It involves knowledge of what will be. The disputed question was where one should place God's hypothetical knowledge of what would be. Is it logically prior to or posterior to the divine creative decree?

Catholic theologians of the Dominican order held that God's hypothetical knowledge is logically subsequent to His decree to create a certain world. They maintained that in decreeing that a particular world exist, God also decreed which counterfactual statements are true. Logically prior to the divine decree, there are no counterfactual truths to be known. All God knows at that logical moment is the necessary truths, including all the various possibilities.

On the Dominican view God picks one of the possible worlds known to Him by His natural knowledge to be actual, and thus subsequent to His decree various statements about contingent events are true. God knows these truths because He knows which world He has decreed to be real. Not only so, but God in decreeing a particular world to be real also decrees which counterfactuals are true. Thus, He decrees, for example, that if Peter had been in such-and-such circumstances instead of the circumstances he was actually in, he would have denied Christ only two times. So God's hypothetical knowledge, like His foreknowledge, is logically posterior to the divine creative decree.

By contrast Catholic theologians of the Jesuit order inspired by Luis Molina maintained that God's hypothetical knowledge is logically prior to His creative decree. This difference between the Jesuit Molinists and the Dominicans was not just a matter of theological hair-splitting! The Molinists charged that the Dominicans had in effect obliterated human freedom by making counterfactual truths a consequence of God's decree. For it is God who determines what a person would do in whatever circumstances he finds himself. By contrast, the Molinists, by placing God's hypothetical knowledge prior to the divine decree, made room for human freedom by exempting counterfactual truths from God's decree. In the same way that necessary truths like 2+2=4 are prior to and therefore independent of God's decree, so counterfactual truths about how people would freely choose under various circumstances are prior to and independent of God's decree.

Not only does the Molinist view make room for human freedom, but it affords God a means of choosing which world of free creatures to create. For by knowing how people would freely choose in whatever circumstances they might be in, God can, by decreeing to place just those persons in just those circumstances, bring about His ultimate purposes through free creaturely decisions. Thus, by employing His hypothetical knowledge, God can plan a world down to the last detail and yet do so without annihilating human freedom, since what people would freely do under various circumstances is already factored into the equation by God. Since God's hypothetical knowledge lies logically in between His natural knowledge and His free knowledge, Molinists called it God's middle knowledge.

On the Dominican view, then, there is one logical moment prior to the divine creative decree, at which God knows the range of possible worlds which He might create, and then He chooses one of these to be actual. On the Molinist view, by contrast, there are two logical moments prior to the divine decree: first, the moment at which He has natural knowledge of the range of possible worlds and, second, the moment at which He has knowledge of the proper subset of possible worlds which, given the counterfactual propositions true at that moment, are feasible for Him to create. The counterfactuals which are true at that moment thus serve to delimit the range of possible worlds to worlds feasible for God.

For example, there is a possible world in which Peter affirms Christ in precisely the same circumstances in which he in fact denied him. But given the counterfactual truth that if Peter were in precisely those circumstances he would freely deny Christ, then the possible world in which Peter freely affirms Christ in those circumstances is not feasible for God. God could make Peter affirm Christ in those circumstances, but then his confession would not be free. Some possible worlds will not be feasible for God to actualize because actualizing them would require that other counterfactuals be true rather than the ones that are—and that is outside God’s control.

So on the Molinist scheme, we have the following logical order (letting the circles represent possible worlds):

Once you grasp the concept of middle knowledge, Lucy, I think you’ll find it astonishing in its subtlety and power. Indeed, I’d venture to say that it is one of the most fruitful theological concepts ever conceived. I’ve applied it to the issues of Christian particularism, perseverance of the saints, and biblical inspiration; Tom Flint has used it to analyze papal infallibility and Christology, and Del Ratzsch has employed it profitably in evolutionary theory.

What begs to be written is a Molinist perspective on quantum indeterminacy and divine sovereignty. For quantum events (if we assume for the sake of argument that indeterminacy is real) are, like human free choices, contingent events. There are, therefore, in addition to counterfactuals of human freedom, counterfactuals of quantum indeterminacy. For example, “If there were a radioactive isotope having such-and-such properties, it would decay at time t.” If statements about indeterminate free choices are either true or false, there’s no reason why counterfactuals of quantum indeterminacy should not be similarly true or false.

In fact, in scientific discussions of something called Bell’s Theorem, which concerns measurements made on paired particles too widely separated to be in causal contact with each other, counterfactuals like “If the position of particle A had been measured instead of its velocity, then the position of particle B would have taken on a correlated value” are usually assumed to be true. Scientists have sometimes remarked that discussions of the counterfactuals involved in Bell’s Theorem often sound like the recondite arguments of medieval theology!

So if counterfactuals of quantum indeterminacy are either true or false, that implies that God’s middle knowledge will include knowledge of just such true propositions. He knows, for example, that if He were to create a physical object in a certain set of circumstances, then specific quantum effects would indeterminately ensue. I think now you can see the implication: by taking into account counterfactuals of quantum indeterminacy along with counterfactuals of human freedom, God can sovereignly direct a world involving such contingents toward His desired ends. Sometimes, these two types of contingents can become interestingly intertwined: for example, God knew that if a grad student in physics waiting in the lab for some event of quantum decay would be delayed going home that evening, he would meet a girl in the hallway whom he would get to know and eventually fall in love with and marry!

So, given quantum indeterminacy, a robust theory of divine sovereignty and providence over the world will require appeal to God’s middle knowledge. For more on this see my book The Only Wise God.

- William Lane Craig