Detecting Design

Okay, well for the life of me I couldn’t figure out what to write yesterday. Tried doing a Junk DNA post, but others have done it better (while talking about a different subject to boot). So I’ll need to come up with something different.

… how about this? I mentioned briefly in a footnote a while back the differences between top-down design and bottom-up evolution.

Believers in Intelligent Design (“It’s creationism but SCIENCEY!”) have a small number of suggested methods for ‘detecting’ design. Dembski’s filter tries to eliminate natural occurances, Behe’s irreducable complexity sets specifications for structures to meet to be the product of design, and a variety of Appeals To Common Sense that don’t really provide anything worth mentioning… but the one thing they have in common is that they all return “true” when applied to biological life.

Interestingly, mainstream science also has a number of methods for detecting, not design, but the results of design. Archeologists look for tool-marks and compare them to tools the humans of the time were known to be using, and SETI looks for mathematical regularities in radio signals known to be produced by the devices of our technological civilisations, etc. Interestingly, both of these examples are cited by IDists as evidence that meanstream science believes detecting design is possible, despite the fact that neither of them returns true when applied to biological life: DNA synthesisers don’t leave ‘tool marks’, and known mathematical regularities within organic life (for example, bilateral symmetry) are more simply explicable as the result of optimisation, not of design. Occams Razor wins again.

So why do the IDists methods return true? Partly at least this seems to be the result of confirmation bias. The Intelligent Design movement is a direct descendant of the religous creationism movements, so the design detection methods were themselves written people with the intention of confirming what they already believed. It’s no surprise that they would return the value their authors wanted them to.

But that’s not entirely it: the authors might want their algorithms to return true, but that doesn’t change the fact that the algorithms themselves do return true. So what are they detecting?

The difference seems to be that mainstream science looks for examples of human, or at least physical, design. The IDists look for any type of design, and they find it.

This isn’t actually a false positive: progressive optimisation via natural selection is a type of design. But it’s a natural, unguided form of design. Richard Dawkins dubbed it the “blind watchmaker”.

I’ll approach this with an example. Since I’ve already written about Behe’s abuse of Mullerian Interlocking Complexity, here’s William Dembski’s Explainitory Filter, in his own words:

Given something we think might be designed, we refer it to the filter. If it successfully passes all three stages of the filter, then we are warranted asserting it is designed. Roughly speaking the filter asks three questions and in the following order: (1) Does a law explain it? (2) Does chance explain it? (3) Does design explain it?

Dembski then provides an example from American law: Nicholas Caputo, a democratic senator, put the democrats in first place on the ballot papers in 40 out of 41 instances. This provides a statistical example for Dembski’s filter:

Unbeknownst to Caputo, he was not employing a reliable random process to determine ballot order. Caputo was in the position of someone who thinks she is flipping a fair coin when in fact she is flipping a double-headed coin. Just as flipping a double-headed coin is going to yield a long string of heads, so Caputo, using his faulty method for ballot selection, generated a long string of Democrats coming out on top.

In selecting the order of political parties on the state ballot, Caputo employed a reliable random process that did not favor one political party over another. The fact that the Democrats came out on top 40 out of 41 times was simply a fluke. It occurred by chance.

Caputo, knowing full well what he was doing and intending to aid his own political party, purposely rigged the ballot line selection process so that the Democrats would consistently come out on top. In short, Caputo cheated.


Naturally, the filter (and the court) disregard the first two options and rule in favor of the third.

Now let’s apply Dembski’s filter to biological life. If you read the source article linked above, and after you’ve taken an painkiller to get over the fallacy-induced headache, you’ll note that Dembski never really applies it to life himself. Instead, he cites a variety of scientific hypotheses that “get around” the necessity of a conclusion of design when applied to biological life. (most of which are actually more related to Abiogenesis than Evolution, but he disparagingly mentions Darwin (with bonus points for the shoutout to YEC’s)* so I’m going to use modern life).

So let’s find something small and cute to apply Dembski’s filter too. I know: say hi everyone!


The appearance of adorable salamanders is something that always happens, given a world like ours and 4.5 billion years of time. Uh, no. Not that we can re-run the simulation to find out, but I think we can rule out axolotyls as a physical law of the universe.

This species formed by random chance: some completely different animal, like an elephant, just up and gave birth to the first axolotyl by means of an extremely unlike complete-genome mutation. I think we can eliminate chance as well.

Ergo: Dembski’s filter concludes the axolotyl was designed.

But… at this point, Intelligent Designists smugly call it quits. “It was designed, musta had a designer.” But how was it designed? What was the ‘designer’ looking for in an axolotyl? IDists don’t look this far: they’ll tell you it’s about detecting the presense of the designer, not analysing it’s motives.

But careful examination of the axolotyls features (of any feature of any species on earth, really) reveals what the “designer” was after: ability to make new axylotyls. From the display tentacles to the body structure, all the features are either oriented around the continuation of the species, or just along for the ride: remnants of old features that were also oriented around the continuation of the species. This heavily implies the Bottom-up design that the natural process of evolution produces, not the Top-down stuff we associate with human/intelligent design.

That confirms what biologists already knew via other lines of evidence: that the “designer” was just mutation and natural selection. It’s a shame the IDists always stop looking just before realising this conclusion.


*footnote: Dembski implying Darwin came up with the age of the earth. Charles Lyell’s remains must be generating quite a bit of torque by now (hey look, an alternative energy source!).

Thus Darwin, to prevent the probabilities from getting too small, had to give himself more time for variation and selection to take effect than many of his contemporaries were willing to grant (cf. Lord Kelvin, who as the leading physicist in Darwin’s day estimated the age of the earth at 100 million years, even though Darwin regarded this age as too low to be consonant with his theory).

“In the future, politics will be redundant. World leaders will be ultimately decided by whoever can genetically engineer the cutest species of axolotyl to use in their campaign ads.”

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