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The Unmistakable Imprint of Purpose — Response to a Theistic Evolutionist


I’ve been discussing my book Undeniable with Hans Vodder, who favors the evolutionary explanation of life. In our fifth exchange, Hans referred to what has been called a “natural nuclear reactor.” Whatever it was, it seems to have existed eons ago in the rock formations of what is now the Oklo region of Gabon. Hans thinks this so-called reactor may have exhibited the kind of functional coherence I point to as a hallmark of invention, making it a noteworthy counterexample to my argument.

I responded by suggesting that reactor is an overblown term for what was really nothing more than a reaction. Back in its day, that Oklo reaction required only: 1) a moderately large uranium deposit, and 2) a source of water to percolate through it. This, I said, doesn’t qualify as high-level functional coherence.

I brought up the comparison to an adjustable wrench — a very modest example of functional coherence. How is it, I asked, that people expected natural nuclear reactions to be found but no one expects a natural adjustable wrench to be found?

Here is Hans’s reply:

Your two-condition assessment of the requirements for the reactor seems a little minimalistic. The Kuroda study (cited in the Scientific American article) mentions four general conditions, and Maynard Smith and Szathmary describe further particulars in The Major Transitions in Evolution. The latter authors mention things like the 45 degree tilt of the sandstone and underlying granite layers which allowed the reactions to occur in a self-sustaining manner; the increased solubility of oxidized uranium, which helped it accumulate in the delta in the first place; and so on. So whether something is considered functionally coherent might depend largely on how relevant conditions are assessed.

But suppose we go with the two-condition assessment. There still doesn’t seem to be anything in the bare definition of functional coherence — “the hierarchical arrangement of parts needed for anything to produce a high-level function — each part contributing in a coordinated way to the whole” (144) — that would exclude Oklo. Consider this adaptation of figure 9.3 from your book:

A critic might reasonably argue that Oklo qualifies as functionally coherent. To make the case more “extensive,” all said critic would have to do is add a few more components or break down the current ones into further detail.

Now, I  suspect this doesn’t really capture the property of “functional coherence” that Undeniable is after. But here’s the rub: It does seem, so far as I can tell, to satisfy the definitional criteria laid out in the book. If that’s right, then one of two conclusions seems to follow. Either:

a) Oklo is a genuine case of functional coherence, with the result that nature can produce at least some functional coherence (pace the “Summary of the Argument” on p. 160 of Undeniable), or

b) Oklo is only a superficial case of functional coherence, with the result that further criteria are needed to distinguish Oklo-type cases from genuine ones.

Sure. Going strictly from my bare definition, one could easily call things functionally coherent that, as you say, don’t really capture the sense of the term as used in Undeniable.

So, I agree with your b option, except I would say context is needed instead of criteria, and I think the book supplies that context. In other words, my definition of functional coherence should make sense to readers who have followed the discussion up to the point where that term is introduced (more on that in a moment).

With respect to Oklo, keep in mind that Maynard Smith and Szathmary, being evolutionary biologists, wanted to “see some parallels with the origin of life” (p. 20 of their book). This raises the possibility that they saw what wasn’t really there.

Here’s a more objective account of the requirements for a uranium-235 fission chain reaction from the Department of Physics and Astronomy at Georgia State University:

If at least one neutron from U-235 fission strikes another nucleus and causes it to fission, then the chain reaction will continue. If the reaction sustains itself, it is said to be “critical,” and the mass of U-235 required to produce the critical condition is said to be a “critical mass.” A critical chain reaction can be achieved at low concentrations of U-235 if the neutrons from fission are moderated to lower their speed, since the probability for fission with slow neutrons is greater.

Strictly speaking, then, all that’s needed for a sustained nuclear chain reaction is a critical mass of uranium-235. Uranium is number 92 on the periodic table of elements, so it literally belongs on the bottom layer of the hierarchy in that figure (you can’t get more elementary than an element). Despite all the fuss over Oklo, then, it really didn’t rise above the behavior of that one element.

Interestingly, Maynard Smith and Szathmary acknowledged the obvious fact that “the Oklo reactor does not look like a man-made reactor.” My question is — what makes this so obvious?

The answer is hinted at by the way these authors inadvertently portray the Oklo reaction as though it had been intended. For example, they say “some moderator material was needed to slow down neutrons.”


The raw fact is merely that water happened to be present as a moderator, causing the neutrons to be slowed. To say that water was needed is to imply not just that something important was at stake but that this was somehow recognized at the time — as though the Oklo reaction had been arranged for a purpose.

Neither Maynard Smith nor Szathmary believed that for a moment, but somehow they couldn’t keep themselves from implying it. Their next sentence reads: “Perhaps most surprising of all, the reaction had to be self-regulating.” Really? Who says it had to be self-regulating? And what definition of “regulate” are we using here? All the usual definitions invoke purpose.

Returning to raw facts, the evidence suggests that the rate of fission at Oklo may have oscillated, peaking when water was present and dropping when it was absent. But again, so what? Fission chain reactions are always limited. They end when critical mass is exhausted. So the suggestion that Oklo was “regulated” is just plain odd. Regulated to what end?

By the time I introduce readers of Undeniable to functional coherence, they know the book is all about purpose. In that context, they know purpose is at the heart of this term. Our design intuition tells us that “tasks that we would need knowledge to accomplish can be accomplished only by someone who has that knowledge.” Despite their exaggeration, Maynard Smith and Szathmary knew full well that the Oklo reaction wasn’t an accomplishment. Indeed, we can’t see Oklo as a task that required things to be cleverly arranged because it shows absolutely no sign of having been that.

With sufficient cleverness and determination, the elements from the periodic table can be arranged to accomplish tasks that aren’t even hinted at by the properties of the elements themselves — challenges whose solutions have to be dreamed up by fertile imaginations. We instantly spot the fruits of those imaginations by spotting their characteristic functional coherence. Dragonflies. Smartphones. Nuclear power plants. Even adjustable wrenches.

I’m sure this reasoning can be formalized, Hans, but do keep in mind that Undeniable isn’t meant to be that. Undeniable shows in a commonsensical way how it is that no one confuses things like radioactive rocks for inventions and, conversely, how no one confuses things like adjustable wrenches for accidents.

Nothing you’ve said so far challenges that main thesis, Hans. So if we’re in agreement there, I’m wondering why you think life should be exempt from reasoning that works everywhere else.

Photo: A dragonfly, by winterseitler via Pixabay.