Editor’s note: It’s a busy publishing season. Dr. Axe’s book, Undeniable: How Biology Confirms Our Intuition That Life Is Designed, is just out in paperback. We noticed that it’s #1 on Amazon’s list of bestselling new releases in the Organic Evolution category. And guess what’s #2? It is the forthcoming title by biologist J. Scott Turner, Purpose and Desire: What Makes Something “Alive” and Why Modern Darwinism Has Failed to Explain It. Not bad! More on Dr. Turner’s book and the pre-publication special offer is here.

This is the fifth installment of my conversation with theistic evolutionist Hans Vodder about my book Undeniable (for Parts 1 through 4, see here, here, here, and here respectively). Hans opens the next part of our exchange as follows:

Before moving on, I want to summarize our disagreement over accurate probability calculations. It’s grossly oversimplified, but see what you make of this.

I basically agree with Martin Nowak’s statement, “You cannot calculate the probability that an eye came about… we don’t have the information to make this calculation.” If he’s right and we don’t have enough information to get reasonable evolutionary calculations off the ground, then we aren’t able to say they exceed a particular threshold of improbability (such as Dembski’s universal probability bound of 1/10¹⁵⁰). In which case the proper response on the mathematical likelihood of evolution is agnosticism.

However, I understand your point as saying we do have reasonable probability estimates which are well beyond the universal probability bound, even if we cannot say exactly how far beyond. Does this seem right? Obviously our disagreements run deeper, but maybe we’ve started by misunderstanding what each of us means by “accurate probability estimates.”

Now, as for the last post’s questions:

(1) I provisionally agree that living organisms exhibit extensive functional coherence.

(2) I don’t know if “things with extensive functional coherence are necessarily too improbable to be stumbled upon by accident.”

My agnosticism on the second question has to do with the concept of functional coherence. I worry it admits counterexamples and is defined somewhat vaguely. I’ll mention a possible counterexample and discuss the vagueness issue next time.

Consider the natural nuclear reactor which occurred at Oklo, Gabon (I refer interested readers to this Scientific American article). It’s tempting to think the reactor consisted of a “hierarchical arrangement of parts needed… to produce a high-level function” (Undeniable, 144). If that’s fair, then the Oklo reactor is an important counterexample to the claim that functionally coherent systems are “necessarily too improbable to be stumbled upon by accident.”

Even if one doesn’t buy that, the Oklo reactor at least seems to undermine the Universal Design Intuition that “Tasks that we would need knowledge to accomplish can be accomplished only by someone who has that knowledge” (Undeniable, 20). One might think that if anything qualifies as a task which requires knowledge to accomplish, stably splitting the atom would! In any case, I am curious to know what you make of the Oklo reactor.

Thank you, Hans, for pausing to summarize our positions on probability calculations. Very helpful!

I agree that we don’t have a way to calculate the probability of an eye appearing by unguided evolution, but I don’t agree that this leaves the matter undecided. Your example of a natural nuclear reactor makes my point nicely, I think.

Let’s compare the qualitative likelihood of natural geological processes producing a sustained nuclear reaction to the qualitative likelihood of these processes producing, say, an adjustable wrench. Somehow, without any calculation at all, we’re all certain that geological processes can’t make a wrench. Moreover, we’re right to be certain of this.

In Undeniable I show how our intuitive certainty on matters like this connects to the more formal reasoning that we happily forgo. In the language of the book, the making of an adjustable wrench is a whole project — “a big result accomplished only by bringing many small things or circumstances together in just the right way.” (p. 69) More precisely:

[T]hose small things and circumstances must be arranged in a functionally coherent way, such that they all work together to produce something considerably more significant than the sum of the parts. Arrangements of this kind never happen by accident because they can’t happen by accident. (p. 159)

We know a lot more about making wrenches than we do about making eyes. Nevertheless, the probability of a wrench happening by accident is no more calculable than the probabilities for an accidental eye or accidental instructions in alphabet soup or accidental digital pictures. I never calculated any of these. Rather, the point I make in Undeniable is that our confidence that such things are effectively impossible is fully justified even without numerical estimates of the probabilities.

The justification comes from the extreme (and therefore obvious) mismatch of scale. To illustrate this principle with money, consider that while I don’t have even a rough estimate of the balance in your checking account, Hans, I nevertheless know you can’t cut a check to pay off the US national debt. I know this because I know the scale of the national debt to be far greater than the scale of individual wealth.

Similarly, our experience of accidental causes shows that they produce virtually no functional coherence. Consequently, when we see something that exhibits an abundance of functional coherence, we immediately recognize it as being far, far beyond the reach of chance.

As for the Oklo nuclear reaction (the term “reactor” is a stretch), since most people have no idea what sustained nuclear fission requires, they have no way to gauge whether it can happen by accident. Interestingly, the article you cite tells us that people who do know the requirements judged them to be modest enough that they predicted these natural fission reactions would be found well before they were found.

The requirements are indeed modest. The atomic nucleus of uranium-235, a natural form of uranium found in the earth’s crust, has a natural tendency to split when struck by a neutron. When that happens, a few neutrons are thrown off, each of which has the potential to strike another uranium-235 nucleus and cause another split, causing more neutrons to be thrown off, etc., etc. So, nuclear chain reactions are an inherent aspect of certain elements, including uranium.

Back when the Earth’s supply of uranium-235 was less decayed than it is now, all that was needed for an Oklo-like reaction was a moderately large uranium deposit with water percolating through it (which slows the neutrons down, enhancing their splitting ability). Uranium deposits are out there, and water is never very far away. I count two required circumstances, then—one only moderately rare and the other so ubiquitous that it can be assumed.

That’s not an example of extensive functional coherence.

In thinking through your reservations about functional coherence, Hans, it may help for you to reflect on how people who know natural adjustable wrenches will never be found knew that natural fission reactions would be found. I think you’ll end up affirming something essentially equivalent to functional coherence as the answer.

Photo: Williams adjustable wrench, by J.C. Fields via Wikicommons.