Divine Omniscience, Human Freedom, and Backward Causation

Many attempts have been made since Boethius’ ill-fated effort to deduce a contradiction from the conjunction of the propositions that there exists an essentially omniscient God and that there are free creatures. One version of such an argument that has yet to receive a decisive refutation attempts to show that this conjunction entails the conceptual impossibility that it is possible for causation to go backwards. This argument does not work against a God that is omnitemporally rather than timelessly eternal, for it is required that for every event that occurs God believes at every time prior to its occurrence that it will occur. Thus, if successful, the argument gives a powerful reason for conceiving of God as timelessly eternal, that is, as not being subject to any temporal determinations or distinctions. Another option is to have God remain omnitemporally eternal but deny that a prediction of a free act has a truth-value prior to its occurrence, thereby precluding even an omniscient being from knowing it in advance. And since an essentially omniscient being will not believe any proposition that it does not know, this being will not have any prior beliefs about this act.

The argument arbitrarily picks out some apparently free creaturely act, say Jones’s freely mowing his lawn at t₂, and attempts to show that this has the consequence that Jones has the power to backwardly cause God to have had a certain belief prior to t₂. And since this is conceptually impossible, it is false that Jones freely mows his lawn. This conclusion can be generalized to every apparently free creaturely act. The argument that is to be presented is a variant of one given by Nelson Pike.[1]

1. God exists. premise

2. God is essentially omniscient. By definition

3. God is omnitemporally eternal in that he exists at every moment of time without beginning or end. premise

4. For every event that occurs, God believes at every time prior to its occurrence that it will occur. from 2 and 3

5. Jones freely mows his lawn at t₂. assumption for an indirect proof

6. Jones could have refrained from mowing his lawn at t₂. from 5 on the assumption that an act is freely done only if the agent can refrain from doing it

7. It was within Jones’s power at t₂ to bring it about that eighty years ago God

believed other than he did. from 4 and 6

8. It is conceptually impossible that anyone have the power to bring about a

past event. Necessary truth

9. It is false that it was within Jones’s power at t₂ to bring it about that eighty

years ago God believed other than he did. From 8

10. It is false that Jones freely mows his lawn at t₂. from 5-9 by indirect proof

Following Ockham’s way out, many have denied premise 8, claiming that in a certain type of case, of which step 7 is an instance, it is possible for causation to run backwards. There are numerous cases in which a person can now act so as to bring it about that a proposition about the past is false. For example by acting as I do now (e.g., selling state secrets to a foreign power) I bring it about that the patriots labored in vain, by pumping out Smith’s stomach that he did not take a fatal overdose, by engaging in a great buffalo hunt that Jones had not engaged in the last great Buffalo hunt, and by making a hit that wins the game and the series for Brown’s team that Brown was not the goat of the World Series when he committed a game-winning error in an earlier game.

What these past tense propositions have in common is that they report what obtains during some time interval in a way that makes demands on what happens or fails to happen at later or earlier times. They could be called “temporally impure propositions.”[2] Consider a proposition of the form “S is F.” It reports what its participial nominalization, “S’s Fing,” refers to. The proposition that “S is F” is temporally impure just in case that S’s Fing obtains during interval of time t either entails that there is a time earlier or later than t or is not consistent with any number of occurrence of S’s Fing earlier or later than t. Thus, any proposition that reports a first or last occurrence of S’s fing will count as temporally impure as well any proposition that reports what obtains at some interval of time that entails that something happens or fails to happen at some earlier or later time, which entails that there is some time earlier or later than that time.

It turns out that the propositions r and s are temporally impure by this criterion. That God believes at t₁ that Jones will mow his lawn at t₂, unlike the proposition that some nonomniscient being, Smith, believes this, is temporally impure because it entails that there is a time later than t₁ at which Jones mows his lawn. Surprisingly, the proposition that God exist at t₁ also is temporally impure; for it is a conceptual truth that a temporally or omnitemporally eternal God exists at every time without beginning or end in any world in which he exists. Thus, if God exists at a time t₁, he exists at every time later than t₁. Therefore, that God exists at t₁ is temporally impure because it entails that there exists a time later than t₁.

It might be claimed that even though the proposition that God exists at t₁ is temporally impure, still it is absurd to claim that anyone could bring it about that it is false that God exists at t₁, or that it is false that he timelessly exists. By acting so as to bring it about that it is false that God exists at t₁, one does not causally prevent God from existing but instead does something that logically precludes his existing. That I now am in Pittsburgh does not causally prevent me from now being in San Francisco but rather logically precludes that I am. Thus, by being in Pittsburgh now I bring it about that I am not now in San Francisco. Now what could a free creature do that would logically preclude God from existing? He merely need freely do something that is so evil that it logically precludes God’s existing, such as bringing about that all sentiment beings, of which there is a great multitude, forever exist in the most horrendous state of pain and misery. This logically precludes God’s existing, since God, in virtue of having middle knowledge of what created free people will do, would not allow this to happen. Or, even if he does not have middle knowledge, at a certain point he would intercede so as to eliminate this great suffering.

John Martin Fischer has argued with great ingenuity that if we permit someone to bring about a temporally impure proposition about the past, we must also permit her to do so for a temporally pure one; but, since we do not want to permit the latter, we must not permit the former, thereby destroying the Ockhamist rebuttal of Pike’s argument.[3] There are two different alleged ways in which this occurs. In the first case, there is a temporally impure proposition that logically entails a temporally pure one. For example, that God believed at t₁ that p logically entails by Existential Generalization that someone believed at t₁ that p. Fischer could then urge that if Jones at t₂ can bring it about that God believed at t₁ that p, he can bring it about that someone believed at t₁ that p, since the former entails the latter. The latter is a temporally pure proposition, and thus in bringing about the former temporally impure proposition one also brings about the latter.

My response to this reductio ad absurdum objection is as follows. I take it without argument, though I am prepared to argue the matter, that “causes it to be the case,” “brings it about,” and “explains” create opaque contexts and thereby take abstract propositions as their relata, which is fitting since what is needed in an opaque context is a sense (which is what a proposition is) or concept. Because “brings it about” creates an opaque context, it is not closed under deduction. If it were closed under deduction, it would follow that, since a necessary proposition is entailed by any proposition, I can bring about that 2+2=4 if I can bring it about that any proposition is true.

The second case involves two coreporting propositions (propositions whose participial nominalization are coreferring), one of which is temporally impure and the other of which is temporally pure. Lets assume that God is Bob’s favorite object. This has the consequence that the proposition that God believe at t₁ that p, although not identical with, is coreporting with the proposition that Bob’s favorite object at t₁ believed p. The latter is temporally pure. But, Fischer would urge, if it is conceptually possible to bring about the former, the same must also hold for the latter.

Because “brings it about” creates an opaque context, we shouldn’t expect that coreporting propositions are inter-substitutible salva veritate. Thus, it cannot be inferred from the proposition that Jones can bring it about at t₂ that God believed at t₁ that p that Jones can bring it about at t₂ that Bob’s favorite object at t₁ believed that p. But why we should prefer one propositional way of describing the event of God’s believing p at t₁ over the other. I have no answer to this question, since it rests on context-sensitive considerations. But for the purpose of Pike’s atheological argument it must be the proposition that God believed at t₁ that p that is employed, for he could not derive any freedom-canceling conclusion if his argument uses the proposition that Bob’s favorite object at t₁ believed that p.

Another one of Fischer’s examples assumes the quite dubious proposition that God cannot have a belief unless his mind is in some sort of representational state. Let us assume that God’s believing that p involves as one of its mereological parts God’s mind being in representation state S. God’s believing at t₁ that p is identical with God’s mind at t₁ being in representational state S. Therefore, the proposition that God believed at t₁ that p is co-reporting with the proposition that God’s mind at t₁ was in representational state S. The latter, unlike the former, is temporally pure. But if Jones at t₂ can bring about the former he can also do so for the latter, the reason being that if a person can bring about a given proposition, he can bring about any proposition that is co-reporting with it. However, this latter principle—that “bring it about” is closed under co-reporting propositions—has nothing to recommend it. Consider the proposition that at t₁ Jones is dancing the first day of a two day dance. This is a paradigm temporally impure proposition. It is conceptually possible for someone subsequently to t₁ to falsify it by killing Jones so that he cannot go on dancing. Yet the event of Jones’s dancing at t₁ the first day of a two day dance is identical with the event of Jones’s dancing at t₁. And thus the proposition that Jones dances at t₁ the first day of a two day dance is co-reporting with the proposition that Jones dances at t₁. But it would be unreasonable to demand that one can bring it about that the former is false only if he can bring it about that the latter also is false.

Richard M. Gale

University of Pittsburgh

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[1] “Divine Omniscience and Voluntary Action,” Philosophical Review, 74 (1965), 27-46.

[2] The account that I will give of them is a refinement on the one I gave in The Language of Time (London: Routledge & Kegan Paul, 1968).

[3] See especially Chapter 6 in his The Metaphysics of Free Will (Oxford: Blackwell, 1994. I have taken the liberty of reformulating his objection in terms of my pure-impure proposition distinction rather than in terms of his hard-soft fact distinction. There are some differences between these distinctions, but they do not affect any of the points that will be made.