Saturday, December 29, 2007

Best Books of 2007 - Science

In a recent First Things article, Avery Cardinal Dulles presents three Catholic schools of thought regarding evolution: strict (theistic) Darwinism, in which God oversees the scientifically random events that produce higher life forms; Intelligent Design, in which God intervenes in the evolutionary process to produce steps that could not occur randomly; and the philosophical critique of the lack of explanatory power in Darwinism. Cardinal Dulles professes sympathy with the third, and I suppose I would as well. "As a matter of policy," he writes, "it is imprudent to build one’s case for faith on what science has not yet explained, because tomorrow it may be able to explain what it cannot explain today. History teaches us that the “God of the gaps” often proves to be an illusion."
True as this is, and much as I am personally reluctant for the same reasons to embrace Intelligent Design (understood as this particular movement; I believe in an Intelligent Designer!), Michael Behe continues to make me think hard about whether there really are gaps in evolution. In his first book, Darwin's Black Box, he introduced the concept of 'irreducible complexity'. I was pleased to see Cardinal Dulles adopt the term in his article. The idea of irreducible complexity is, roughly, that a system such as the human immune system is a complex of numerous subsystems, many of which are interdependent on another. If one system 'randomly mutates', it breaks the system. There have to be several mutations at once to build such a mechanism, and the potential for this to happen randomly starts to look more paltry.

This argument appealed to me when I first read it and still does. As a non-biologist, I had an intuition about this problem while studying evolution in college. I used the idea of a 'step function' to describe it. A step function (in calculus) produces a graph with gaps in it. There is a not a smooth transition from one value to another (e.g. "Round up to the nearest whole number" is a function that cannot produce any values between 5 and 6). In the case of the reproductive function of chromosomes, for example, sexual animals can only have offspring with members of species that have the same amount of chromosomes (this is before cloning). The more complex animals have more pairs of chromosomes. So how does one go from being a chimpanzee (22 pairs) to being a human (23)? If a human-like chimp is born with 23 pairs of chromosomes, it might be intellectually superior to his fellow simians, but he is, alas, sterile. So we have to posit two random mutations of the same sort at the same time in the same geographical vicinity, and then we have the problem of Cain and Abel all over again: so imagine that two mutant chimpanzee/proto-humans manage, against even the remotest odds, to produce offspring with 23 pairs of do their offspring ensure their own survival? What if the litter only produces males, for example? The difficulties in these scenarios boggle lesser minds such as my own, and these scenarios must be played out many, many times for Darwinism to work.

Whenever I've posed these problems to real, live biologists (I have a sister who is one of them), the response is usually something like, "well, you have to understand that this whole process takes a long time, but in two billion years of evolution, enough of these random coincidences add up to make evolution work." Behe's newest book, The Edge of Evolution: The Search for the Limits of Darwinism, puts this staple Darwinist assumption to a scientific test.

Side note: this is also one of my frustrations with Darwinism, that it does not qualify as an empirical science, strictly understood. We can't set up controls and variations in a laboratory and reproduce random mutations. Thus there is no test for Darwinism...until now.

Behe notes that in the ten years since Black Box the science of genetics has undergone an exponential development. Among other advancements, we have now decoded the whole human genome. We can isolate the genes for certain structures in the human body, and therefore we know what needs to change for a mutation to take place. This previously was part of Darwin's 'Black Box' the mechanism that Darwin himself admitted needed to be taken for granted for evolution to work.

We've opened the box, and the grandeur of what is inside astounds me. Behe, in terms fitting for laymen, describes the genetic and chemical arrangements that make possible the construction of a bacterial flagellum. The jaw-dropping complexity and ingenuity (sorry, I can't help but ascribe this to God at this point) opened my eyes to a new level of beauty in the universe. I mean, if you or I had to build a living flagellum, we'd be pretty hard-pressed, but in real life the flagellum builds itself! And it does so by means of cascading chemical programs hard-wired into the genes of the bacterium. The mechanism would make Rube Goldberg jealous.
More intriuguing from a standpoint more scientific than aesthetic is Behe's investigation into real random mutations. He points out that at any one moment, there are more malaria organisms in the world than there have been vertebrates throughout history. Since the malaria organism is less complex than a vertebrate, we should expect that it will mutate faster for survival advantage.
What we find in studying malaria is that evolution is better at breaking things than at building new and improved things. So indeed malaria does mutate to get around certain drugs, but in a weakened strain. Importantly, malaria, with more chances at mutating than we human have ever had, has not 'figured out' how to survive in sub-tropical temperatures. Similarly, sickle cell anemia provides protection against malaria (note that this is another breaking of a mechanism, what Behe calls 'trench warfare'), and in centuries of available time and googles of mutations, malaria hasn't cracked the code to 'learn' how to bond to sickle cells.
Behe's analytical skills have been considerably honed in controversy since the excellent Black Box. More importantly, the scientific evidence in his books deserves to be reckoned with. While it is bad policy to look for God in the gaps, one can hardly deny that the gaps are there.


Bob said...

Fr. Peter,

I wish I could find the link but I couln't but I think it was a TEDS talk ( on irreducible complexity. It used the examples of the flagella and blood clotting. The theory that all of the genes must be present for the characteristic to exist and if one is missing, life would be rendered inviable. I can't remember all the science but I recall some of the stuff on the blood clotting. In humans, clotting requires 23 (number might be wrong) genes. This system was thought to be irreducibly complex. Until you see that dolphins have blood that clots--with only 15. And that puffer fish have blood that clots with only 9.

I wish I could find the really made me look at that particular argument much more closely.

Anonymous said...

Um, dude, before you start saying evolutionary biologists don't know what they are talking about, check your facts:

The more complex animals have more pairs of chromosomes.

Wrong. Amoebas, ferns etc. can have hundreds of pairs of chromosomes. There is no real correlation with complexity. Chromosomes can be all different sizes and contain vastly different amounts of DNA. ("Amount of DNA" in the genome doesn't correlate with complexity either, google "c-value paradox" and "onion test").

So how does one go from being a chimpanzee (22 pairs) to being a human (23)?

Actually chimps have 24 pairs. So do the other great apes, except humans which have 23. Whoops!

If a human-like chimp is born with 23 pairs of chromosomes, it might be intellectually superior to his fellow simians, but he is, alas, sterile.

Humans have *fewer* chromosomes than chimps. Humans "lost" a chromosome when it fused with another chromosome. Scientists have traced the fusion to human chromosome #2, which lines up perfectly with 2 chimp chromosomes.

This was all described by Ken Miller in the Dover trial. Heck, Michael Behe even agrees with it in The Edge of Evolution.

Maybe you should double-check a few things before dismissing an entire field as dubious...

Prior Peter, OSB said...

Dear Bob & Anonymous,
Fair enough: I am not a biologist--as I stated. I will admit my mistake regarding chromosomes, but the basic argument I was using isn't affected by the different data. So a chimpanzee is born with two chromosomes fused. Am I not correct in saying that he/she can no longer reproduce with the regular chimpanzee population? That is the basic problem that I haven't seen addressed. If you can address it, I will drop the argument. For now, I will just get my facts straight.

I should make it clear that I believe that evolution is, in the words of Pope John Paul II, 'more than a theory'; that is I believe that somehow evolution is real. I just find serious problems with Darwin's theory. As I wrote, I am personally not eager to sign on to Intelligent Design, in large part because so many evolutionary biologists don't see a need for it; Behe's work raises better and more informed objections to strict Darwinism than my sophomoric ones.

Bob said...

Fr. Peter,

Overlooking the tone of Anonymous' comments, he brings up a good point about the complexity and "higher" life forms. I think a lot of people associate higher with more intelligent, more advanced, ...superior?

You didn't specifically make this point but this was something that made me appreciate evolution. Evolution is not a progression from lower to higher but rather a gradual perfection of each life form--just through different paths. Mollusks won't one day evolve into the "higher" human just as we did not evolve from a mollusk. But each of us, millions of years ago, shared a common ancestor neither human or mollusk. Mollusks took their path and we took ours.

As a Christian, this thought brings greater appreciation for all forms of life and the beauty and complexity with which the Creator has endowed each. The slow process of perfection makes (for me) an interesting "type" for sanctification while reinforcing the dignity and value of all of creation.

I guess I find evolution and Darwinism to enhance my love of God rather than threaten it.


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