In a recent post, Victor Reppert asks:

Is there any theistic argument [from/in natural theology] that can’t be accused of being a god-of-the-gaps argument? Is this an all-purpose reply to all natural theology?

My answers are “yes” to the first question and “no” to the second question.

I think it would helpful if everyone would agree upon or stipulate what it means for an argument to be a “God-of-the-gaps” argument.

Here’s my proposal: “God-of-the-gaps” arguments have the following logical form.

(1) There is some puzzling phenomenon P which science cannot at present explain.

(2) Theism does explain P.

(3) Therefore, P is more likely on the assumption that God exists than on the assumption God does not exist.

The key feature of this argument–and what makes it a “God-of-the-gaps” argument–is premise (1). The focus is on science’s present inability to explain P.

For example, here’s a God-of-the-gaps argument from consciousness.

(1) Science cannot explain consciousness.

(2) Theism does explain consciousness.

(3) Therefore, consciousness is more likely on the assumption that God exists than on the assumption God does not exist.

But not all arguments in/from natural theology need have this logical structure. For example, they could be presented as what I have called “F-inductive arguments.” If we let B be our background information, E be the evidence to be explained, and H1 and H2 be rival explanatory hypotheses, then F-inductive arguments have the following structure.

1. E is known to be true, i.e., Pr(E) is close to 1.

2. H1 is not intrinsically much more probable than H2, i.e., Pr(|H1|) is not much greater than Pr(|H2|).

3. Pr(E | H2 & B) > Pr(E | H1 & B).

4. Other evidence held equal, H1 is probably false, i.e., Pr(H1 | B & E) < 0.5.

The key feature of this argument is premise 2, which does not make reference to science’s inability to explain P.

To make this more concrete, here’s a non-God-of-the-gaps, F-inductive version of the argument from consciousness. E is the existence of human consciousness; T is theism; and N is naturalism.

1. E is known to be true, i.e., Pr(E) is close to 1.

2. N is not intrinsically much more probable than T, i.e., Pr(|N|) is not much greater than Pr(|T|).

3. Pr(E | T & B) =1 > Pr(E | N & B).

4. Other evidence held equal, N is probably false, i.e., Pr(N | B & E) < 1/2.

Whatever problems may exist with that argument, being a God-of-the-gaps argument clearly isn’t one of them.