Steven Berven of the blog Tattered Bits of Brain was kind enough to respond to my post “Why Fight Creationism?” (see link above) in a new post called “It’s alive (or, yet another creationism post).” I don’t mean to be unkind, but there is a bit of goal-post-shifting, reductio ad absurdum, and other “classic” rhetorical devices used throughout, suggesting that evolution is every bit as much as “just-so story” as creationism is.
Steven starts off with a disclaimer;
If I haven’t made it clear before, let me reiterate: I don’t in any way mean to suggest that creationist views and religious ideology should supplant the scientific method. I enjoy science. I love learning about the way our world works and the amazing complexity and interdependence of the life and natural processes of this world.
I just don’t happen to think it within the realms of possibility that it could all just ”happen” through a series of random accidents and fortuitous spontaneous breakthroughs.
I never suggested Steve was a YEC, only that YEC arguments are not only unscientific, they’re simply ill-founded assertions that find their roots in devotion to Biblical authority. Steve seems to fall along the theistic evolution/intelligent design section of the continuum, and while Steve is more than welcome to have whatever beliefs he wants regarding the origin and evolution of life, I feel that both theistic evolution and intelligent design require at least some amount of special pleading and a requirement to bend a bit to spiritual/religious notions.
Anyway, on to the meat of the argument. In the last post in this series, I gave a summation of early tetrapod evolution in non-technical terms (see “Why Fight Creationism?“, and also “Taking in the Carboniferous Atmosphere“). Steve has some problems with my explanations/use of rhetoric language, however;
An external change gave the tetrapods a “good reason to develop their lungs.” Okay, so they’ve got the reason. Now what? Do they think to themselves, “Hmm, guess it’s probably a good time to develop lungs. Ready…..GO!“
Clearly a silly example; or is it? Examples such as these seem so suggest that species respond in an almost cognitive fashion, and that this somehow results in a kind of genetic memory that is imprinted on their DNA. What’s the real answer? “Evolution,” (as in the proper noun) was kind enough to “pre-adapt” species (and by that I take to mean “build in?”) the capability to exploit a new niche? So Evolution pre-engineered in capabilities? Tetrapods were given a reason to developed their lungs? Lobe-finned fish responded to selective pressure, pushed up on their arms, and “decided” to leave the water in order to avoid death? The water murks up, the plants move in, and you have a choice: adapt or die. So you adapt. Huh?
In this little discourse Steve is trying to paint my summation in an anthropomorphic or vitalistic light, something I myself have spoken against before. If one looks back at the original post we’re discussing, I try to take an ecological approach to tetrapod evolution, showing how selective pressures would have favored those animals better able to survive and reproduce in plant-clogged swamps near the edge of insect-filled forests. I did not suggest some vitalistic force, driving the animals on internally, nor the early tetrapods thinking “I want to have some bugs for lunch, so I’m going to develop lungs and do away with my gills.” This is clearly absurd, and perhaps I could have chosen my words better when I said that tetrapods had “good reason” to become more developed to land. I had assumed that there was a basic understanding that those early tetrapods that were better able to exploit the changing environment would be more successful, leaving more offspring which would have their own variations, and the duel pressures to develop lungs and to take advantage of new food sources provided plenty of selective pressures for populations of these animals to change.
Steve also mentions my explanation that tetrapods were pre-adapted to evolve in that they already possessed rudimentary lungs and a locomotor system that could easily be modified. I was not suggesting that evolution “knew what was coming” or acted like some spiritual guiding force, urging on the animals. Rather the previous evolution of the tetrapods gave them an advantage when things started to change, and if the early tetrapods did not have lungs or fleshy fins with strong-enough bone structure, the vertebrate “invasion” of the land would likely have had to wait. The point I was attempting to get across is that as ecology changes, some animals are favored over others, natural selection (and other factors) working on variations and systems already present in animals, further modifying them into new forms. It is no accident that all living tetrapods share the same basic body plan; it was inherited from our early ancestors, and it has proved efficient enough that it only need be modified through evolution rather than constructed from scratch every few hundred million years. In any event, in case it was not already clear, evolution does not work like some abstract supernatural force, like some natural toolkit of “Mother Nature”; organisms change together in ecologies, and there is no prediction of what is going to happen next, so changes in ecology favor some and not others, those that were pre-adapted to do better in a different world allowing natural selection and other mechanisms to further adapt the organisms.
Steve continues along with a similar absurd argument, implying that early tetrapods just didn’t know they could breathe air until they were forced to, somehow then realizing their opportunities. As I’ve just described, this is an attempt to ridicule a straw-man argument so much as to make the position of the opposing side seem untenable, but I said nothing of fish as prescient as the ones Steven describes. Steve continues;
This is exactly the kind of intellectual sleight of hand that causes me the most trouble with much of the current evolutionist theories. To vaguely suggest that “Nature” did it or “Evolution” did it is NO DIFFERENT than saying that “God” did it! Do you see what I’m trying to get at here?
Again, this is creating a straw-man argument via reductio ad absurdum. The whole point of my last entry, taking special care to mention Romer’s “drying pond hypothesis” was to present the best model we now have, even though the model may change. It’s a good hypothesis, but we don’t have all the information as yet (there’d be no work to do if we did), and part of the major difference between evolutionary science and ID/creationism is that evolutionary scientists actually make hypotheses and modify them as better evidence becomes available. Trying to ascribe a belief in the God of Evolution like that of creationists in the Judeo/Christian God is a poor argument at best, and as I’ve already shown, has little to do with what I actually described. Then Steve shifts the goalpost down the field;
What I want evolutionary theory to provide me, to provide us, to provide science the world over, is reproducible evidence of the the internal, bio-chemical mechanism whereby RNA and DNA, all those little peptides and amino acids are re-arranged or reprogrammed, how from one generation to the next they are imparted with new replication data that results in a different species, one now better suited to live on land, rather than water. How does “Nature” pre-adapt a species to a range of potential changes? And on a wide enough scale to ensure viability?
This is quite a different aim than wanting to know how tetrapods crawled out of plant-choked swamps onto land, involving the sciences of inheritance, genetics, biochemistry, and many others. Indeed, science has made great strides in figuring out the genetic code and how mutations come to be expressed in future generations, but such explanations would be a book in and of themselves, and fortunately, other authors have already carried this subject. For those unfamiliar with such sciences, a good place to start would be Futuyma’s textbook Evolution and Sean B. Carroll’s Endless Forms Most Beautiful and The Making of the Fittest. As always, there’s still plenty of work to be done, but evolutionary science isn’t merely playing connect-the-dots with fossils, either.
Steve leaves us with this;
I’ll readily admit that much of my data on evolution might be a bit dated, as I’ve kind of been out of the “fight” for a few years. However, from what I’ve been able to gather, evolutionary theory is still long on what happened, and a little short on the how it happened. And to me, if you continue to insist on the what, without being able to provide the how, well then my friends, you are operating in faith as surely as that Bible-thumping creationist.
Again, this reflects a bit of goal-shifting. The “what” and the “how” can vary greatly depending on what level of organization we’re talking about, even though it’s all connected together. Lines of research intertwine and support each other, and scientists are not obligated to agree whatever is new or just seems to “make sense.” A recent example of a smaller-scale evolutionary change involved male butterflies decimated by bacteria, only to bounce back within a few generations. I’ve already covered the story here, and it provides a good example of scientists looking into researching evolutionary changes. Still, as far as fossils go, some information is just not available to us; we’re probably never going to find any genetic material from early tetrapods or be able to study it directly. Does this mean that everything scientists say is therefore “junk”? Of course not, and studying ancient ecosytems as a whole through time can give us some great information about changes in ecology working on individuals and populations of animals. In the end, however, those who would prefer to subscribe agency to a deity or other supernatural force will continue to do so and continue to disagree with me, and that’s fine, but I utterly reject the idea that evolutionary science is merely a new form of religion that seeks to design it’s own creation mythology than learn about how life came to be on this planet.