The Solution to the Omniscience / Free Will Dilemma

Have you ever heard someone ask, “If God is omniscient (i.e., all-knowing) and therefore already knows what I am going to choose, then how am I free to choose?” What the question is fundamentally asking is, How can God’s omniscience and human libertarian free will possibly coexist?Before answering the question, let us first define some terms. The standard definition of omniscience says that, for any person \(S\), \(S\) is omniscient if and only if \(S\) knows all true propositions and believes no false proposition. What this entails is that God, being omniscient, must know the truth value of all future tense propositions (e.g., Jones will sign with the Saints); He would be said to have foreknowledge of the events described by these propositions.On the standard definition of libertarianism, a person \(S\) has libertarian freedom of the will if and only if, when given a choice to do either \(x\) or \(\neg x\), nothing determines the choice that \(S\) will make; he simply exercises his own causal powers to either choose \(x\), or to refrain from choosing \(x\).Finally, fatalism is the view that everything that happens does so necessarily (i.e., it could not have possibly happened any different from the way it did in fact happen).

With those definitions in mind, let us now get back to the question that was posed. For many people, it would seem that omniscience implies fatalism: if God already knows what I’m going to choose, then I can’t possibly choose differently because, if I were to, it would entail that God would be wrong about what He believed that I would choose (i.e., He would have believed a false proposition); which would thus entail that He is not in fact omniscient.

Is there any way to reconcile free will and omniscience and solve this “dilemma?” Yes, there is. For starters, what needs to be understood is that logic of this sort commits a modal fallacy: it is what medieval philosophers called confusing the necessitas consequentiae (necessity of the consequences or the inference) with the necessitas consequentis (necessity of the consequent). Formally, the reasoning is as follows:

1. \(\square(P \implies Q)\)

2. \(P\)

3. \(\overline{\therefore \square Q}\)

Let \(P\) represent the proposition “God believes Jones will sign with the Saints.” Let \(Q\) represent the proposition “Jones will sign with the Saints. When we plug these variables into the argument, we get

  1. Necessarily, if God believes that Jones will sign with the Saints, then Jones will sign with the Saints.
  2. God believes that Jones will sign with the Saints.
  3. Therefore, necessarily, Jones will sign with the Saints.

Why is this reasoning a fallacy of modal logic? Because the proper inference is \(3’\): Therefore, Jones will sign with the Saints. Did you catch the difference between \(3\) and \(3’\)? The latter excludes the word necessarily. Indeed, all that follows from the premises is that Jones will sign with the Saints; it does not follow that he will do so necessarily. When the time comes to make the choice whether or not to sign with the Saints, Jones is completely free to do as he pleases—he can either sign, or not sign. Thus, his choice—no matter what it is—will be a contingent truth; not a necessary truth.

What premise 1 entails is that if God believes that Jones will sign with the Saints, then he will sign with the Saints. But it is not necessary that God believe this. Indeed, the source of God’s belief here is the free choice that Jones will make when the time comes. Suppose when the time comes Jones will choose to sign; God will have known that all along. But suppose instead that when the time comes Jones chooses not to sign; all that follows is that God would have believed that all along instead. Hence, there is no dilemma.

Posted in Defensive Apologetics, Logic.
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