This article is the second in a four-part series about the three distinct ways to formulate the argument for an intelligent cause based on the fine-tuning of the constants of nature. Look here for the first part of the series.

In his article “Has the Multiverse Replaced God?” William Lane Craig presents the fine-tuning argument using the process of elimination. Like every argument by elimination, Craig’s formulation begins by enumerating all possible explanations for the problem of fine-tuning. He writes:

Accordingly, a teleological argument appealing to cosmic fine-tuning might be formulated as follows:

1. The fine-tuning of the universe is due to either physical necessity, chance, or design.
2. It is not due to physical necessity or chance.
3. Therefore, it is due to design.

Physical Necessity 

The first possible explanation for fine-tuning is physical necessity. This means that either the constants are necessary, brute facts of reality or that they deterministically derive from a deeper necessary law of physics. As physical necessity is not a very good theory to begin with (it doesn’t seem plausible that physicists will be able to derive the precise values from a deeper theory) and, more importantly, it doesn’t explain why the constants are fine-tuned (this just remains an immense coincidence), it’s reasonable to discard physical necessity as an explanation of fine-tuning.

Chance

The second possible explanation for fine tuning is chance. If there is only one universe, physicists calculate that it would be incredibly unlikely that the values of the constants would be in the small range that would allow our complex universe to exist. Chance only becomes plausible if there are a tremendous number of alternate universes with different values of the constants — a multiverse. 

However, the multiverse fails to be a good solution for numerous reasons. These include: the Boltzmann brain problem, the measure problem, and the fact that positing an untestable speculative theory of an infinite number of observable universes is a clear deviation from the tried-and-true scientific method. For these reasons, we can eliminate chance as an explanation of fine-tuning.

Intentional Design

With the elimination of two of the three possible explanations of fine-tuning, we are left with the only remaining explanation: the values of the constants are the result of intentional design by an intelligent agent.

Craig’s argument by elimination has the distinct advantage of being rather simple to present and understand. However, it is not without its drawbacks. First, an argument from elimination only works if you can conclusively show that your initial list of possibilities is exhaustive. While it might intuitively seem that there are only three possibilities, a person always suspects that you might be missing a possibility. In fact, Lee Smolin has a creative possibility, Cosmological Natural Selection, that’s different from physical necessity, chance, and design. While Smolin’s theory has deep flaws, the point remains that Craig’s list is not exhaustive. Although we agree (that once you include Smolin) there are no other possibilities, this formulation of the argument can leave a person with doubt that perhaps other possibilities are omitted as well.

There’s a second drawback to using an argument by elimination. To be confident that the sole remaining explanation for fine-tuning (design) is correct, the other possibilities must be fully eliminated. The problem is that while it’s easy to find serious difficulties with the first two theories, it’s very difficult to eliminate them entirely. But if you only show that the first two possibilities are very unlikely, one may suspect that certain questions may render the design explanation unlikely as well. 

To get around this problem and reasonably conclude that the design explanation is correct, one must analyze the design explanation and show that it’s more likely than the other two possibilities. This leads to comparing probabilities — the approach of the second formulation of the fine-tuning argument. We’ll analyze this formulation next time.