Thursday, August 14, 2014

Understanding and Belief

Keith Blanchard (who apparently has no particular expertise in biology) has written a column for The Week that has gained some attention.

The ostensible purpose of his article is to exhort people to embrace evolution as science and not as a matter of faith. As Blanchard says, we should understand evolution, not believe in it. If his point is simply that we can grasp the basic points of evolutionary theory without making a doxastic commitment to them ourselves, well, then that seems a little banal. If his point is that if you understand those points you will presumably believe them then his point is manifestly, glaringly false.

Moreover, it's misleading. Most people who reject evolution are not so much hostile to the idea of some kind of universal relationship of living things. What they object to is the way naturalistic metaphysics is smuggled in with the less innocuous aspects of the evolutionary package.

I might add that I have no quarrel with evolution. It may be true for all I know. My quarrel is with naturalism and naturalistic views of evolution which tell us that evolution is a blind, unguided, completely natural process. That's a claim that goes well beyond the empirical evidence. In other words, we may have arrived here through some sort of descent through modification, but if so, there's much reason to believe that there was more to our existence as a species than purely unintentional, unintelligent, physical processes like mutation and natural selection.

At any rate, Blanchard offers a summary of the basic claims of evolutionary theory which, were they correct, could apply to any kind of biological evolution, naturalistic or intelligently directed. The problem is, Blanchard's summary describes evolutionary theory as it stood about fifty years ago. Few evolutionists accept Blanchard's view today as anything more than a heuristic for elementary school children.

Here's his summary with a few comments. For a much more extensive critique of Blanchard's essay go here.

Blanchard writes:
  • Genes, stored in every cell, are the body's blueprints; they code for traits like eye color, disease susceptibility, and a bazillion other things that make you you.
No doubt our genes code for many aspects of our physical body, but Blanchard does not say that they code for everything that makes us us and for good reason. There's no genetic explanation for some our most important traits. It's a mystery, for example, how genes could possibly produce human consciousness, or many behaviors in the animal kingdom. How, after all, does something like an immaterial mind arise from material interactions of chemical compounds? Not only do we have no explanation for how conscious experience arises in individual persons, we have no explanation for how such a thing could ever have evolved by physical processes.

The same is true of behaviors. All birds of any particular species behave similarly, but how do genes, which code for proteins which in turn form structures or catalyze chemical reactions, produce a behavior? It's no more clear how molecules of DNA can produce behavior than it is how molecules of sucrose can produce the sensation of sweet.
  • Reproduction involves copying and recombining these blueprints, which is complicated, and errors happen.
Yes, they do and those errors are almost always dysgenic. They detract from fitness not enhance it. Just as an error in copying computer code is much more likely to cause a system to crash than it is to cause it to work better.
  • Errors are passed along in the code to future generations, the way a smudge on a photocopy will exist on all subsequent copies.
As I said above, a smudge is a flaw. As similar "smudges" accumulate the result is not a new and different picture of high quality, it's an increasingly weaker and useless representation of the old.
  • This modified code can (but doesn't always) produce new traits in successive generations: an extra finger, sickle-celled blood, increased tolerance for Miley Cyrus shenanigans.
These examples, particularly the last, are dysgenic to human beings. Polydactyly may not be dysgenic but neither does it confer a survival advantage. If it did it would spread through the population, but it hasn't.
  • When these new traits are advantageous (longer legs in gazelles), organisms survive and replicate at a higher rate than average, and when disadvantageous (brittle skulls in woodpeckers), they survive and replicate at a lower rate.
This is the selectionist theory of evolution, i.e. that natural selection, acting on genetic mutations, drives evolution. It is held today by few biologists because it's fraught with empirical difficulties. In order to finesse these difficulties biologists have adduced other mechanisms such as genetic drift to do the heavy lifting in evolution.

In fact, as Michael Behe pointed out in his book The Edge of Evolution, any theory based on fortuitous mutations defies probability. Many traits require more than one specific mutation occurring fairly rapidly in an organism, and the chances of this happening are astronomically poor.

I repeat, this might have happened through a long evolutionary process, but to say that the process was completely natural (a claim Blanchard doesn't make, by the way) is to go beyond empirical science and enter the realm of faith and metaphysics, and even the belief that it happened at all requires a considerable amount of blind faith.

We can understand the basic hypothesized lineaments of the process, but that doesn't mean that it's appropriate to believe that the process actually happened. To believe in it is to have faith that the theory is the true explanation for how we got to be here. There are people who understand the theory and who believe it's true. There are people who understand the theory and don't believe it, and there are many who understand it and are agnostic, believing that the scientific evidence often conflicts with the theory, as Stephen Meyer has so powerfully shown in his two books Signature in the Cell and Darwin's Doubt.

In my opinion, a humble agnosticism with respect to the means by which life originated and diversified is the most intellectually prudent course. I'm far more confident, however, in the truth of the claim that however we came to exist as a species it's far more probable that it was the result of the purposeful agency of an engineering genius than that blind chance accomplished the equivalent of producing a library of information entirely unintentionally.