Darwinism: Science or Philosophy

Chapter 10a
Response to K. John Morrow, Jr.

Michael J. Behe

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This paper is a response to a presented paper.

Original author's comments on this response.

THE CONCLUSION THAT Professor Morrow draws from the history of theories of antibody diversity is a splendid, shimmering, jewel-like example of the ability of a theory, here materialistic evolution, to supply "facts" to the true believer that the mere, neglected, primary data in no way warrant. The believer looks upon the most innocuous facts and sees in them a stunning confirmation of his theory, where a person who is not committed to the hypothesis sees irrelevant or, sometimes, hostile information. Thus the believer builds a great edifice of pseudo-knowledge which, like cotton candy, is spun from a little bit of sugar and a lot of air. Let us, then, try to deconstruct Professor Morrow's argument, separate the solid material from the airy hypothesis, and see if anything is left to build on.

The ability of the immune system to respond to an invasion by virtually any foreign substance is truly amazing and, as Professor Morrow has told us, until recently it had puzzled scientists. An understanding of what such a system might look like was hampered for a long time by a lack of data, which is almost always the case in science. So, in the absence of sufficient relevant data, scientists tried to come up with an explanation for antibody diversity in terms of concepts that were available at the time. Thus, since it was known that antibodies were proteins and that proteins were flexible polymers, it was speculated that. well, maybe antibodies wrap themselves around a foreign substance and somehow freeze into that shape, somehow. Or maybe, since proteins were known to be coded by genes and since the mammalian cell had enough DNA to code for a lot of proteins and since host defense is so vitally important, well, maybe there is a very large number of such genes. Or maybe, since it was known that changes, mutations, in genes could occur, maybe somehow the mutation rate for cells that produce antibodies is cranked up very high, so that many different types of antibodies could be produced without requiring coding in the DNA. Or maybe it was a combination of some of these. Or maybe it involved something no one suspected.

As it turns out, the explanation of the basis of antibody diversity had to await a startling discovery: genes coding for proteins often do not occur contiguously-- essentially they are genes in pieces. This means that, for example, the piece of DNA that tells how to make the lefthand portion of a given protein can be separated from the piece that tells how to make the middle portion, which can be separated from the piece that tells how to make the righthand portion. In the cellular process that "reads" the information, the disparate messages are joined together and a single, continuous protein chain is produced.

It was subsequently seen, as Professor Morrow has mentioned, that genes coding for antibodies are generally broken into four pieces: the V, J, D, and C regions. Now, there are a number of copies of each of these regions, differing one from the other, in the germ line of an individual. When cells that make antibodies develop in the body, a clever trick is employed. Instead of one set of V, J, D, and C pieces always joining together, as is the case for the pieces of most other proteins, any V can join with any J and they can join with any D and any C. This increases the number of combinations fantastically. Let us assume, for the purpose of argument, that there are 100 different V regions, 100 different J regions, etc. Then the number of different combinations of V and J are 100 times 100, and the combinations of V, J, and D are 100 times 100 times 100, and the combinations of V, J, D, and C are 100 to the fourth power, which is one hundred million. So a very large number of combinations can arise from a very limited number of genes. This is the currently accepted explanation for the generation of antibody diversity.

Professor Morrow has indeed selected a very elegant biological system to discuss. He has shown us that the mechanism for the production of antibody diversity is very clever, that complexity is generated from a finite number of components, that this mechanism is for all practical purposes able to deal with virtually any foreign material in the body, and that to a large degree it is through the efforts of science that we have come to understand how this system works. What Professor Morrow has not told us, however, is how he knows that such an elegant system evolved in a nondirected manner.

The question of what route the evolution of such an intricate system might have taken is also left unaddressed. Instead his argument sets up several straw men which he then proceeds to knock down. The first straw man set up to serve Professor Morrow is the notion that a materialistic, mechanistic explanation for the functioning of a biological system, as opposed to such an explanation for its origin, is a refutation of the idea of purpose. To my knowledge no one at this conference has advanced the idea that, say, the foot, the head, or the digestive tract operate in anything other than a mechanistic fashion. But plenty of people profess to see purpose in their functioning. The fact that the immune system is a mechanism says absolutely nothing about whether it has a purpose.

The second straw man found in the preceding talk is the notion that one of the original hypotheses on antibody diversity, the germ line hypothesis, was somehow put forward to save teleology, as if the hypothesis was popular mostly in seminaries and Bible colleges. In fact, even a cursory look through biochemistry textbooks of recent years and the original literature shows a distinct lack of religious allusions when the germ line theory is discussed. It is difficult to guess why that hypothesis should bear the burden of teleology.

In the final analysis, then, the only positive argument that Professor Morrow advances to defend the idea that the system for generating antibody diversity actually evolved is theological: God wouldn't have done it that way. Professor Morrow informs us that the germ line model was the one God would have selected, but that the germ line model is incorrect. Therefore, one infers, God does not exist or at least does not mess with biology. Materialistic forces are all that are left to get the job done, so nondirected evolution must have produced antibody diversity.

But why is the germ line model approved by the deity? Well, because, "the creator could look into the future and know what antibodies would be required." The theological insight in this statement is breathtaking! By the same reasoning we can know that our hands are strong evidence for evolution since the creator could look into the future and see that we would eventually need bottle openers, scissors, and corkscrews, and would therefore have appended Swiss army knives to the ends of our arms. With his keen appreciation for theological issues Professor Morrow apparently has decided that a creator would not provide flexible, multipurpose, clever tools to his creatures.

Regrettably, I have no formal theological training, so Professor Morrow's argument is wasted on me. The only advanced work I have done is in science and I must rely on results from that discipline to reach a conclusion. If I may, then, let me return to the immune system and suggest some questions that science can at least in principle address, though perhaps not at the present time.

One definitionn of "evolution," according to Webster's Ninth Collegiate Dictionary, is "a process of continuous change from a lower, simpler.... to a higher, more complex state." Certainly Professor Morrow would agree that Darwinism must hold that the immune system of the higher eukaryotes did not come suddenly into being, but that it must have developed gradually from a simpler system. What difficulties would that development have to overcome? The first problem, of course, is the origin of life, but we will pass over that here.

The second difficulty is the origin of splicing. How at first did different regions of a nascent "message" get hooked together in the proper order and the intervening sequences edited out, and, more important, how likely is that mechanism, which in the modern world requires many different proteins, to have developed through a nondirected search?

The next hurdle is inserting the antibody into the cell membrane. But even then a cell with an antibody in its membrane is useless unless there is a specific feedback system simultaneously to cause the cell to proliferate and to begin exporting soluble antibody. This will require another two to three proteins. In this respect a cell with just an antibody would be like a person holding a steering wheel, looking for a car to hook it on. If all of these difficulties are eventually overcome we have a population of cells exporting antibodies that bind to a given antigen. But, as stated in the popular textbook Biochemistry by Voet and Voet (page 1114), "Antibodies, for all their complications, only serve to identify foreign antigens. Other biological systems must then inactivate and dispose of the intruders." To an invading agent, being bound by an antibody is like being shot with a dart gun: the dart may stick, but it does no harm. Thus after an organism has gone to all the trouble of developing a diverse array of antibodies that can recognize many foreign bodies, it is still virtually helpless. In modern-day organisms, after intruders are identified by antibodies, a completely different pathway called the "complement system" actually kills or gets rid of the invader. The complement system is a highly regulated pathway of more than a dozen different proteins. How did the interdependent antibody and complement systems develop, step-by-step; what was the selective advantage to the organism for each step along the way; and what are the odds that such an intricate system would develop in a nondirected search?

As I stated earlier, questions such as these are within science's sphere of competence, and until the questions are answered in their favor by experiment, proponents of nondirected evolution have no right to cite the fantastic, intricate, clever immune system as evidence for their views.

A number of proponents of naturalistic evolution are fond of saying that "the theory of evolution is about as much in doubt as that the earth goes around the sun." They seem not to notice that the proposition that the earth does go around the sun, although once controversial on religious grounds, is now universally accepted. Nondirected evolution, however, remains as controversial as when it was first proposed. The reason for these different receptions is that strong evidence has been produced by science to support the solar system, but convincing evidence of the truth of Darwinism has not yet been produced. Until such evidence is produced, no theological, philosophical, or cotton candy arguments will quell the controversy. Until then every person has the right, on solid scientific grounds, to regard Darwinism as an interesting but very doubtful hypothesis.

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