Sooner or later, any discussion with a modern anti-evolutionist will come around to some variant of Michael Behe’s hypothesis of “irreducible complexity.” For those who don’t follow the peculiar antics of
Creation Scientists Intelligent Design Theorists, Behe posited that there was no way an ‘irreducibly complex’ feature or system could evolve, because such a system would fail in its function if even one of its parts didn’t exist during the evolutionary process. He then went on to provide a few examples of irreducible, like the bacterial flagellum.
I’m not going to savage any of those particular examples in any depth here, as they have been so thoroughly debunked by every internet skeptic and her dog/cat/drop-bear that it would be fair to say they have no bunk left. They are bunkless. Their quantity of bunk is conspicuous by it’s absence. (and yet, the page header for Uncommon Descent is still the bacterial flagellum. There’s a difference between science and pseudoscience right there: science acknowledges when it was wrong)
There are two aspects of the Irreducibly Complex argument I want to deal with, and just to be different to everyone else they’re not going to be “irreducibly” and “complex”. The first aspect is that of a feature for which no viable evolutionary predecessors exist.
This is actually a perfectly reasonable argument. Such a feature could exist, and if found would provide major problems for the theory of universal common descent. It’s one of the ways the theory could be falsified.
But where evolutionists and pseudo scientists differ is our take on what to do about such a find. Anti-evolutionists are, for unscientific reasons, eager to find the silver bullet or garlic sausage that will kill the theory in one hit. So whenever they find something that looks even slightly silvery, or smells just a little garlicky, they proudly load it in their monster-hunting gun and fire. This causes quite a mess when it turns out to have been a radish sausage, and the big evolutionary monster just gives them a funny look and wanders off. Seriously, who carries a sausage gun around anyway? (Note to self: build a sausage gun. That sounds totally badass and not at all Freudian)
Scientists, on the other hand, apply the scientific method and come up with more than one viable hypothesis. Yeah, maybe it’s silver, but maybe it’s just shiny lead or nickel or mercury at -40 degrees Celsius. So they go looking for the viable evolutionary predecessors the anti-evolutionists are so quick to claim don’t exist. And so far, they have a pretty good track record when it comes to finding them.
The second concept behind Irreducible Complexity is the claim that a feature is recognisable as having no viable predecessors: the claim that if it fits into certain parameters, it can’t possibly have evolved naturally.
To avoid slandering the good name of Behe, because he’s certainly done an excellent job of it without my help, I’ll quote him directly here rather than paraphrasing:
“By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. (Darwin’s Black Box: The Biochemical Challenge to Evolution, p. 39)”
Now, credit where credit is due, this concept of a group of parts none of which can be removed without resulting in the collapse of the system, didn’t originate with Behe. Nobel Prize winner H. J. Muller beat him to it by a few years: seventy-eight, to be exact.
Oh, one other difference between Muller and Behe: Muller posited this sort of complexity as an expected consequence of evolutionary mechanisms. That’s right: irreducible complexity is a prediction of the theory of evolution. Here’s what Muller wrote in 1918:
“… thus a complicated machine was gradually built up whose effective working was dependent upon the interlocking action of very numerous different elementary parts or factors, and many of the characters and factors which, when new, were originally merely an asset finally became necessary because other necessary characters and factors had subsequently become changed so as to be dependent on the former. It must result, in consequence, that a dropping out of, or even a slight change in any one of these parts is very likely to disturb fatally the whole machinery; for this reason we should expect very many, if not most, mutations to result in lethal factors …” (Muller, H. J. (1918) “Genetic variability, twin hybrids and constant hybrids, in a case of balanced lethal factors.” Genetics 3:422-499. [Free Text, Genetics Online] )
(Yeah, I’m quoting stuff from TalkOrigins. Normally I’d be more original, but I’m pressed for time and they’ve already said much of what I wanted to say. Nonetheless, extensive copy/pasting makes me feel like an internet troll, so I apologise most emphatically and promise to commit sepuku as soon as I get my hands on an appropriately oriental-looking sword.)
Shorter Muller: Interlocking Complexity can evolve gradually if you add an unnecessary part that aids the basic function, and then make it necessary by changing or removing other parts to require it.
For a ridiculously simple example of this (yes, I’m going to thief an example from that TalkOrigins article again. I’m so cheap), imagine three stepping-stones making a causeway across the river. Adding a plank of wood across the top of them allows you to get across without having to jump from stone to stone. Now removing the middle stone allows the water to flow underneath the plank, so it won’t overwhelm the bridge. This simple bridge: two stones and a plank, is an example of interlocking complexity: remove any part and the bridge ceases to function. Yet, even using a ridiculously oversimplified and limited version of evolution, in which the only available mutations are ‘add’ and ‘remove’ (what happened to incremental modification?), it’s possible to evolve it from simpler precursors.
My favourite example of this sort of analogy, despite (okay, ‘because’) it’s long, overly complicated, and kind of ridiculous, is the evolving mousetrap.
So, if interlocking complexity can evolve, if it was in fact predicted to evolve using evolutionary mechanics known to Muller almost a century ago, how on earth did Behe, a fully accredited molecular biologist, come up with his hypothesis that it can’t? And why are Intelligent Designists the internet over still pulling out this sad argument in favour of design? [WARNING: ramblings ahead]
That’s a question I simply can’t answer. I could speculate, I could draw from my limited knowledge of psychology to cast unfortunate implications all over their motives and intellectual capacity, I could come up with idea’s and methods to counter the misinformation and attempt to teach them… but I suspect I’m incapable of understanding their reasons on a more base level.
I’m a skeptic: my internal programming, both consciously and subconsciously, does it’s darndest to ensure that that my personal beliefs are influenced solely by reality. I don’t know how to communicate effectively to those who base their beliefs on desire and emotion. I could tell them they’re wrong as much as I like, but if they’re not convinced by reality itself then what effect are my measly words going to have?
Ultimately I think convincing a denialist of the simple truth that reality is what it is, whether they be of the evolution, climate-change, age-of-the-universe or any other varieties, is beyond the communicative abilities of any individual. Deniers gonna deny: the only person who can show them reality is themselves. But something the skeptical community can do is give them access to information. I don’t write posts like this to convince anyone who isn’t already convinced: I fully believe that’s beyond me as an individual. And I also believe that the anti-evolutionists who are willing to approach their own biases with a skeptical eye and a critical mind will sooner or later see reality: no amount of indoctrination can keep a skeptic down forever.
But maybe posts and debates and mainstream skeptical activity are triggering the inner skeptics in others, or helping these people to break free from the denialist mindset sooner. Or maybe it’s just causing them to go into lockdown and man the battle stations to fend off the skeptical invaders… I honestly have no way of knowing.
I guess you can colour me an optimist, though, since I find the former possibility more likely.
“Drop Bears are a carnivorous relative of the Koala, and they make excellent pets providing you don’t have a house with any flat surfaces above head-height.”