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Of Statues and Sponges — Progress in My Conversation with a Theistic Evolutionist

Douglas Axe | @DougAxe

theistic evolution

My recent book Undeniable aims to show how common-sense reasoning validates our intuition that life is designed. Wishing I could sit down with every reader who wasn’t convinced, I have relished the opportunity to “sit down” for an extended dialogue with one of these skeptical readers — Hans Vodder. You can read our entire discussion as a series of posts here.

It has become clear in recent posts that Hans thinks Undeniable uses a form of argument — namely, a probabilistic argument based on discrete combinatorial objects (DCOs) — that he thinks doesn’t apply to life. In my previous response to him, I suggested that the focus on DCOs may have taken us off course.

Here is Hans’s reply:

Doug, let me first say publicly it’s an honor and pleasure engaging you and your ideas here. Probabilistic method is an important issue in the broader evolution-ID debates, so I’m grateful for the opportunity to explore this in detail, even though we clearly have our differences. Thank you for your patience as I try to do your position justice. 

It’s true the words “discrete combinatorial object” do not appear in Undeniable’s pages. However, the issue isn’t whether the book uses DCO-based probability calculations by name, but whether it uses them in practice. If it does, then my criticisms apply.

Van Till here defines a DCO as “an object that is composed of particular kinds of building blocks that must first be gathered into one location and then configured in a particular arrangement to form the complete object.” Is there an equivalent idea in Undeniable?

The idea of functional coherence is very similar. It is “the hierarchical arrangement of parts needed for anything to produce a high-level function — each part contributing in a coordinated way to the whole” (Undeniable, 144). Both ideas treat organisms as wholes composed of precisely arranged parts.

For instance, in an earlier post, you asked readers to imagine a “list of requirements that would constitute a complete specification” of a thing, assign each member of the list a “modestly improbable” value, and multiply these together for the odds of the thing’s chance formation. This way of modeling things—as objects composed of independent parts arranged in a particular way — is just what it means to treat them as DCOs. 

What’s wrong with this? The problem should become clearer if we examine what the method leaves out. It proceeds with no consideration of ancestral populations, precursor systems, environmental conditions, etc. But are these factors truly irrelevant? One wouldn’t think so. In short, the faulty assumption here is two-fold: that an organism can be treated as if it were merely the sum of its parts; and that its biological, historical, and environmental contexts are probabilistically irrelevant. 

This also suggests an answer to the statue problem. Since there is a fundamental disanalogy between inanimate sculptures and living things, a method appropriate for calculating the odds of the former may not be so for the latter.

Thank you, Hans, both for your careful thoughts and for your kind words. I have valued your critical feedback from the beginning of this conversation, and the value only grows as the dialogue deepens!

Two More Things We Agree On

I think we’ve reached agreement on a couple of new points. Not having read Van Till, I didn’t mean to suggest that the argument in Undeniable doesn’t apply to what you’re calling discrete combinatorial objects. It does apply to these things, but it also applies to things I wouldn’t call discrete combinatorial objects — things like lungs (p. 71) and omelets (p. 158) and origami cranes (p. 162) and insects (p. 193) and statues. In other words, the argument I put forward in the book is more general than a DCO argument, I think.

Three Statements

In our discussion, I’ve been using the implausibility of a natural statue — an outcrop of marble carved by wind and weather into a magnificent representation of a human figure — to illustrate my argument. In three statements, I summarized the reasoning by which we know this can’t happen: 

1. The forming of this statue would require surface reshaping that is both extensive and coherent.

2. For natural causes to exquisitely sculpt even a small portion of a human figure — an eyelid or a thumbnail — is improbable.

3. It follows that for natural causes to sculpt the many hundreds of comparably improbable small portions of a human figure — not only in the same chunk of marble but also in their proper proportions and placements — is fantastically improbable.

I know you have more to say on this, Hans, but the fact that you’ve now at least tentatively agreed with this form of argument as it applies to statues is very helpful.

From Statues to Sponges

Undeniable applies the same reasoning to life. Setting the stage for that, I ask readers (p. 80) to consider the blind evolutionary process that supposedly converted a very primitive multicellular animal like a sea sponge into the full array of modern complex animals. The argument against this scenario closely parallels the above argument:

1. The production of any complex animal from a simple sponge-like starting point would require structural and genetic reconfiguration that is both extensive and coherent.

2. For natural causes to accomplish any one of the numerous required changes in a given organism is improbable.

3. It follows that for natural causes to bring about all the necessary changes in a single organism is fantastically improbable.

Now, let’s look at your two reasons for thinking this doesn’t work for life the way it does for statues, starting with your concern that I’m treating organisms as mere sums of their parts.

As an aside, the book should make it clear that this isn’t my view. Taking a high view of wholes, I introduce the term busy whole on page 68, defining this as “an active thing that causes us to perceive intent because it accomplishes a big result by bringing many small things or circumstances together in just the right way.” Wholes are more than sums of parts.

More to the point, I don’t see how our agreement on this helps your case. The above argument rests on the plain fact that all complex animals require lots of different parts (or features or aspects) that are absent from sponges. So, unless you’re contesting that (and I don’t think you are), you aren’t touching my argument.

Moving from Van Till

Based on previous comments, I think perhaps Van Till has convinced you that special circumstances would have to hold in order for statement 3ʹ to follow from statement 2ʹ. But your acceptance of statement 3 following from statement 2 should convince you otherwise. Indeed, very peculiar circumstances would have to hold in order for 3 and 3ʹ not to follow from 2 and 2ʹ.

Moving on to your second concern, I take this to be that statement 3ʹ ignores the many natural factors that affect what might happen to ancient sponges and their descendants. My response is again to refer you back to statement 3. The details of natural effects on sponges are inconsequential to statement 3ʹ for the same reason that the details of natural effects on marble are inconsequential to statement 3.

Statement 3 does ignore a whole lot. As this PhD thesis shows, the material complexity of marble makes the effects of weathering enormously complex in detail. At a conceptual level, however, we can safely categorize all these details as blind — meaning they do what they do without any connection to the art of representing the human form in stone. Only by sheer coincidence would these blind factors produce a human statue, and this dramatically simplifies our analysis. Instead of concerning ourselves with how exactly stone weathers, we merely note the degree of skill or luck that any cause of statues must exhibit. If this exceeds a very modest threshold, then we know luck can be ruled out.

The reasoning behind 3ʹ is exactly the same: However complicated the natural factors that impinge upon sponges may be, they do what they do with no understanding of what would be needed to convert sponges into complex animals — orcas, fireflies, geckos, mice, or anything else. Only by sheer coincidence would these blind factors produce such remarkable things, and coincidence is never that lucky.

Photo: A sponge (Spongilla lacustris), by Kirt L. Onthank [CC BY-SA 3.0].