Re:Irreducible complexity?

With some inevitable irony, I agree (obviously only up to a point) with Mike. There is a reasonable point to the anti-evolutionist arguments he borrows from, although those authors he is borrowing from also take the point beyond its usefulness.

The point is that time per se is a neccessary but not sufficient answer for the origin of biological form and function.

We know that nature has constraints that lead to self-organizing processes, but self-organization as far as we understand it only goes so far and is not found continuously throughout nature in all the places where we find adaptation.

"Selection," and its handmaiden, population genetics, is a powerful but problematic kind of answer as well, because while it certainly helps us understand how useful novelty may spread through a population, it doesn't tell us where the useful novelty comes from. There is no reasonable doubt that population genetics can model the spread of heritable characteristics. It is an empirical science done all the time. However, it assumes that there is something there of value worth spreading.

The idea that variation arises without respect to what the organism needs in its environment is a consequence of both Darwin and modern genetics. We can find only very limited ways in which anything resembling information can flow into the genome, and yet we observe that genotype adapts to the local ecology over time. You have to stretch and squint pretty hard and pretty far beyond science to find any plausible way that adaptation could occur unless by
the Darwinian model.

The legitimate argument is that useful heritable variation is not itself explained by Darwinian theory, just as the origin of the the genetic and metabolic processes fundamental to cellular life are not themselves explained in any adequate way by Darwinian theory. It is a good question whether it is even possible to come up with any single model that can explain how useful variation arises. It surely isn't essential to evolutionary theory as currently applied.

It is taken for granted that mutation and recombination and other genetic mechanisms can somehow be amplified by other means to produce useful phenotypic variation, and it is the specific ways this happens that become interesting. Anti-evolutionists don't care how it happens, they argue from plausibility arguments that it can't in principle explain certain characteristics of living things. That is, somehow, someway, something must have planned it out for certain kinds of useful novelty to have arisen in nature.

Dembski's explanatory filter provides the basic structure of both his and Behe's argument. "Complexity" (which presumably might sometimes include adaptive complexity through Darwinian processes) can be explained naturally, but "X" characteristics cannot. "X" becomes in Dembski's case "complex specified information" and in Behe's case, "irrreducible complexity."

The evidence relevant to selection and the population genetics model is largely irrelevant to them (in fact, Behe sometimes implies vaguely that he is an evolutionist of sorts and that he finds the theory of common origins plausible). For this reason, I find it somewhat disingenuous when people quote Behe when arguing the radical anti-evolutionist position, but I don't suppose constructing carefully reasoned arguments or possessing intellectual integrity are primary strengths among that group.

Behe's core argument is simple and mostly very reasonable. To paraphrase, if something can't have arisen by an variation from a previous form that is insensitive to the needs of the organism, it can't be explained by means of Darwinian mechanisms. Therefore, something else is needed to explain them.

Behe argues that various things like clotting cascades and flagella cannot be explained by variation insensitive to the needs of the organism, from previous forms, and therefore that something else is needed to explain them.

There are several good reasons Behe's argument doesn't work as a defense of radical anti-evolutionism (other than the obvious but weak argument that Behe himself does not seem to consider this a radical anti-evolutionist argument):

1. It is by no means well established that the mechanisms he describes could not have arisen from unplanned variations from prior forms. For the time being, these arguments mostly rest on plausibility.

2. Being unable to explain something as a result of variation insensitive to the needs of the organism does not neccessarily mean planned variation. Behe's link to "intelligent design" is not technically through irreducible complexity, it is through irreducible complexity that must have been planned. If the "design" of flagella arise not just from random mutations but also due to physical constraints at the molecular level, it does not support the "intelligent design" thesis, and its spread through the population is obviously better explained by Darwinian models ("intelligent design" does not have a population model or any reason to have one).

3. The structure of the explanatory filter itself is questionable, since it assumes that it can catch every possible kind of explanation, and so lead to reliable inferences of planning if nothing else seems to apply. Something that cannot be explained through Darwinian adaptation, self-organization, or other means, may still have a simpler explanation rather than require an inference to intelligent planning.

So I argue that Mike is right that time is not a sufficient answer, but that intelligent design is even less sufficient as well as unneccessary!

And more importantly, I argue that their whole argument is irrelevant to evolutionary biology, whose power, evidence, and usefulness they casually ignore while arguing technical subtleties of what Darwinan explanations can explain and what they can't.

kind regards,

Todd

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