Geisler’s Gap

41n+DmrzuIL._SY344_BO1,204,203,200_In the last twenty to thirty years there has been an enormous increase in the number of people engaged in various apologetics-focused ministries. Though it would be hard to trace this increase to any one single person, if you were to make a list of the four or five most influential apologists during that time, Norman Geisler would certainly have to be included on it. For me personally, his co-authored (with Paul Feinberg) book Introduction to Philosophy: A Christian Perspective was the first book in philosophy I ever read and I found it quite helpful. In general, I think today’s aspiring apologists would be well served to model their careers after Geisler.

Overall, I think this rise in apologetics is a good thing. The Christian worldview is being attacked from all sides and the Church needs people who are equipped and able to respond to these attacks. Unfortunately, the quality of some of the arguments by Christian apologists simply doesn’t pass muster. This puts us in an interesting position because we now need to not only respond to those attacking the Christian worldview, but we also need to carefully evaluate the specific arguments of our fellow apologists. Because we agree with their conclusions it’s tempting to ignore fellow Christians’ bad arguments for the existence of God or bad responses to non-believers’ arguments against the existence of God. However, it’s important that we evaluate these arguments too so as to not bring reproach on those arguments that are actually pretty good.

Norman Geisler is not typically one whose arguments stand in need of critique. However, even the best of philosophers can make mistakes from time to time and so, in the spirit of trying to ensure all our defenses of Christianity are the very best, I offer a small critique of an argument Geisler presents in his book If God, Why Evil?

A problem of evil

Geisler begins by noting one of the ways evil can be problematic for the Christian. In his book he addresses the various problems that evil is said to generate and he begins by simply discussing the problem that arises from the nature of evil itself. Now in typically Geisler-ian fashion, he helpfully presents the problem as a simple syllogism.

  1. God created all things.
  2. Evil is something.
  3. Therefore, God created evil (If God, Why Evil?, pgs. 17–18).

Now, of course, if God created evil the immediate question that needs to be asked is, “Why would God do that?” That’s a good question and one that would probably be difficult to answer. However, we’ll see that Geisler doesn’t need to answer that question because he gives us an argument aiming to establish that God did not create evil. Before moving to Geisler’s response, it’ll be helpful to formalize this argument so we can see its structure. To do so, we’ll use the following simple legend.

Tx: x is a thing
Cxy: x created y
e: evil
g: God

With this in place, we can reconstruct the argument as follows.

1*. (x)(Tx > Cgx)
2*. Te
3*. Therefore, Cge

For those unfamiliar with predicate logic, we’d read the first premise as “For any X, if X is a thing, then X is created by God.” The second premise would be read as “Evil is a thing” and the conclusion as, “Therefore, God created evil.” Now it’s important to note that we’ve not changed the content of the argument Geisler presented. All we’ve done is state it formally, and then symbolize it. Why bother with this? Well doing so allows us to bring out the structure of the argument, which is vital to assessing its merit. What we see, then, is that this argument affirms the antecedent and that of course is always valid.

A response to a problem of evil

So how does Geisler respond to this problem? Well, since the above argument is valid the only way to avoid the conclusion is by denying one (or more) of the premises. On Christianity, the first premise is unassailable. So, the only other option is to deny the second premise. This is exactly what Geisler does. What’s the problem, then? Well, as we’ll see, the problem is not with the reasons he gives for thinking premise two is false, but with the conclusion that Geisler tries to get by denying it. Here’s his response.

  1. God created all things.
  2. Evil is not a thing.
  3. Hence God did not create evil. (If God, Why Evil?, pg. 19).

Using the same legend as before, we can formalize this as follows:

1*. (x)(Tx > Cgx)
2*. -Te
3*. Therefore, -Cge

The first premise is the same as before and so equally unassailable, but Geisler, like Augustine before him, denies that evil is a thing. What formalizing these arguments allows us to see is that in saying “Evil is not a thing” Geisler is really saying that the antecedent of (1*) is false. But from that we cannot derive the falsity of (1*)’s consequent (that is, we cannot derive “God did not create evil”). Unfortunately for Geisler, this is precisely what he tries to do in the book. Even though he’s written a very good book on critical reasoning (Come, Let Us Reason) Geisler appears to have not noticed that his second argument commits the logical fallacy of denying the antecedent. We might agree with the conclusion that God did not create evil, and perhaps even have other reasons to believe it, but we simply cannot get that conclusion from this argument. All we can conclude from denying that evil is a thing is that the conclusion of the original argument (God created evil) does not follow from its premises. Even if we think God did not create evil, this argument simply does not permit us to reach the conclusion that he did not create it.

For example, imagine I point out that, “If it’s raining, then the streets are wet.” Well, if you then respond by noting that it’s not raining, we couldn’t validly conclude that the streets are not wet. From those two premises we cannot conclude anything about whether or not the streets are wet. In the same way, from Geisler’s denial of evil being a thing, we cannot conclude anything at all about whether or not God created evil. Geisler’s mistake is to try to use (1)—despite the fact that it’s true—in deducing his conclusion.

Lessons learned

It may be helpful to make two concluding remarks about this little exercise. First, showing that there is a gap in the reasoning for a conclusion is not the same as taking the conclusion to be false. One might agree that God did not create evil, but the reasons for that conclusion would need to be different than the one Geisler gives.

A second, and closely related, thing to note about this is that the goal of providing these critiques is to help generate better arguments for the truth of Christianity. I believe there are good responses to the various problems that evil is said to generate. It’s for that very reason that I think we should not be content with bad arguments to that effect. This is the same reason that Richard Davis and I published our critique of Stephen Layman’s widely cited moral argument for God’s existence. (See, “Layman’s Lapse: On an Incomplete Moral Argument for Theism” in Philo 16: 1–10.) We would be quite happy to see Layman revise his argument in such a way that our criticism no longer applies. Were he to do so, we’d have just one more good argument for God’s existence. In the same way, I hope Geisler considers how to revise this particular response to a problem of evil to avoid committing a basic logical fallacy.

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