I argued in my last post that Plantinga’s probability arguments against naturalism face a serious challenge when assuming the non-contingency of theism (that is, theism is either necessarily true or necessarily false). I want to state those problems clearly, and factor them into the first premise of the Evolutionary Argument Against Naturalism (EAAN) to see how the theist’s general apologetic approach holds up.

EAAN can be stated as the following, where ‘R’ stands for the reliability of our cognitive faculties, ‘N’ for naturalism, and ‘E’ for evolution:

(1) The probability that R is true given N&E is low.
(2) Anyone who accepts N&E and sees that (1) is true has a defeater for R.
(3) Anyone who has a defeater for R has a defeater for any other belief she thinks she has, including N&E itself.
(4) Anyone who accepts N&E thereby acquires a defeater for N&E; N&E is self-defeating and can’t be rationally accepted.[1]

This is meant to get the naturalist to realize that belief in unguided evolution leads to radical skepticism, and the only way to escape the problem is to think of our cognitive faculties as having been designed by a higher intelligence, according to a design plan, and to reject naturalism.

However, the assumption of theism’s non-contingency puts the theist in a sticky situation. On the one hand, if they presuppose that theism is necessarily true, that entails the logical impossibility of naturalism, so no meaningful probability arguments can be made against it. That is, no meaningful probabilities can be assigned to an impossible state of affairs. Plantinga cannot argue (1), “The probability that R is true given N&E is low.” Such a claim would be necessarily false.

On the other hand, to avoid this problem, if the theist presupposes that theism is necessarily false, they now face an EAAN of their own. Call it The Necessarily False Theism Argument Against Theism (NFTAAT), where ‘T’ stands for theism, and ‘R’ stands for the reliability of our cognitive faculties:

(1*) If theism is necessarily false, then anything in conjunction with T will also be logically impossible.
(2*) Anyone who accepts necessarily false theism and T&R and sees that (1) is true has a defeater for R.
(3*) Anyone who has a defeater for R has a defeater for any other belief she thinks she has, including T&R itself.
(4*) Anyone who accepts necessarily false theism thereby acquires a defeater for T&R; T&R is logically impossible and can’t be rationally accepted.

This is a worse spot to be in than the naturalist, who is said only to have probabilistically “low” (or inscrutable) reliable cognitive faculties. Not only can the theist not rationally argue from such a view, but any apologetic argument on its behalf will result in absurdity. Theism would be logically self-refuting. At least the naturalist has the possibility of denying (1).

The Only Way to Save EAAN

The only remaining option for the theist is to presuppose that theism is contingent. This allows them to actually make probabilistic arguments against naturalism, and in support of theism. However, this involves denying God’s existence in some possible world(s); that is, if theism is merely a contingent truth, then there are some possible worlds, possibly ones very similar to our own, where God does not exist.

This introduces many questions. Could it be possible for humans to exist and have reliable cognitive faculties, in a world absent God? Maybe God is not all-powerful, or not worthy of worship? Maybe God herself is a contingent being. I’d have to spend more time thinking about the consequences of adopting such a view. But I have a feeling that most Christian apologists won’t want to take this route. Jesus said,

So I tell you, every sin and blasphemy can be forgiven–except blasphemy against the Holy Spirit, which will never be forgiven. (Matthew 12:31)

Does this include possible worlds?

References

  1. Capturing Christianity, “Discussion: The Evolutionary Argument Against Naturalism,” http://capturingchristianity.com/evolutionary-argument-naturalism/
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