Should the theory of intelligent design be taught in biology classes

A look at how intelligent design is not Biblical creationism and how biological evolution is not what Darwin was talking about

A battle is raging over education in the United States these days. It is being waged by those who believe that alternatives to Charles Darwin’s theory of evolution should be taught in biology classes. Their opponents are mostly mainstream scientists who resist all such attempts to tamper with the curricula. The first group is mostly made up of Christian fundamentalists, and they fall into two main camps: those who wish to see Genesis-style creationism taught, and those who argue for the inclusion of the more sophisticated theory of intelligent design. Should these theories be taught in biology classes?

BOTH OF THESE theories should be taught, although not for the reasons that their proponents hold. And, unlike most opponents of these theories, I believe that their open discussion would make a valuable contribution to the classroom.

Of the two theories, creationism can be dealt with more easily. Basically, proponents of creationism hold that the universe and the Earth were created approximately 6000 years ago, based upon the lineage of people mentioned in the first few books of the Old Testament. They also hold that modern species of plants and animals were created in their present forms, as described in the book of Genesis.

The evidence against this young-Earth creationism comes from both astronomy and geology. Astronomer Edwin Hubble discovered early in the 20th century that the galaxies were flying apart, and by extrapolating backward, astronomers have calculated that our universe is at least 15 billion years old. On Earth, measurements of radioactive decay in rocks have set the age of the Earth to be over four billion years old.

Explaining this to students would illustrate the different ways in which theologians and scientists arrive at conclusions, and give students ammunition to use against creationists. However, the major stumbling block to including young-Earth creationism in the curriculum is that presentation of the theory may be construed as promoting one particular religious viewpoint.

What Darwin’s theory

is and isn’t

Unless one lives on a deserted island, one cannot avoid the fact that Darwinian evolution is a controversial topic. Critics of biological evolution often remark that it is “just a theory,” and so it may not actually be true. There is a sense in which they are right, but it is important to distinguish between evolutionary fact and evolutionary theory.

Biological evolution appears to be a “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.”

- Charles Darwin

historical fact. The fossil record speaks unambiguously of gradual development toward increasing complexity. The deeper you dig, the older the fossils, and they show clearly that there was a time when the Earth was ruled by fish, then amphibians, reptiles, dinosaurs and finally mammals. And there are other lines of evidence for evolution as well. For instance, in early stages of development, the unborn human fetus will show various traits of its prehistoric ancestors, such as gills and a long tail. Evolution is a fact in the same sense that gravity is a fact.

However, there are also theories of evolution in the same sense that there are theories of how gravity works. The first theory of evolution was proposed in the sixth century BCE by Anaximander, who thought that life first developed in the oceans and that humans were descended from fish.

Many educated people before Darwin accepted the testimony of the fossil record and believed that life developed gradually on Earth. However, it was inconceivable to most that life could have developed its stunning complexity without divine intervention. The story of creation in the book of Genesis was thought by some scientists to have occurred over millions of years and not literally in one week.

Darwin’s theory changed

all that

In the early 19th century, Charles Darwin began a detailed study of the fossil record of various species of birds and reptiles in the Galapagos Islands. He pondered the problem of how natural processes could account for the stunning variety found in the natural world and came up with a novel solution. He noted that many more plants and animals were born than survive to maturity, and that there appeared to be random natural variation among members of the same species of plants and animals.

For instance, different members of the same species may be born with altered colouring, taller, faster and with a sharper beak or a longer tail than others. Some of these accidental characteristics of birth may help their owners in the struggle to survive and reproduce. If these characteristics tend to be passed down to their offspring, then with succeeding generations more and more members of the species will possess them. If enough of these small random variations accumulate, over thousands or millions of years very different creatures may emerge. If populations are isolated and forced to adapt to different environments, Darwin’s theory holds that entirely new species will eventually emerge, incapable of breeding with members of their original species.

Darwin’s breakthrough was not the discovery of evolution, but rather the theory of evolution by natural selection operating on random variation. Darwin had thought of a mechanism by which evolution could occur via entirely natural, random processes, not requiring the intervention of a Great Designer.

But, Darwin was a proper Victorian English gentleman and a man of conscience. He realized that his theory would stun his fellow countrymen by showing how all the beauty and complexity of the natural world could have developed without divine intervention. Uneasy with the prospect of undermining religious faith, rather than publicize his theory immediately, Darwin remained silent.

In 1858, Darwin was shocked to receive a letter from scientist Alfred Wallace that laid out in detail the theory of evolution by natural selection. Working independently, Wallace had come to exactly the same conclusions. Realizing he was about to be scooped by Wallace, Darwin rushed to put his ideas into print, and his book Origin of Species was published the following year.

This book rocked the intellectual world like a bomb. At first many resisted the new theory, but it gradually won adherents, and additional work by others added more evidence in support.

In the 1930s, Darwin’s work was combined with the discovery of genes, and the neo-Darwinian theory of evolution was created. In a nutshell, random genetic mutations are thought to occur within an organism’s genetic code. Most mutations are harmful, but beneficial mutations are preserved because they aid survival — a process known as “natural selection.” These beneficial mutations are passed on to the next generation. Over time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature).

Since Darwin’s time, evolution has been observed in action. Moths have become darker as camouflage from predators in response to a sootier environment, and bacteria have become more resistant to antibiotics. Most critics of evolution do not deny that organisms have evolved in this manner. Rather, they want to know if evolution by natural selection can explain how there came to be moths and bacteria in the first place.

It must be stressed that Darwin’s theory of evolution is a slow, gradual process. It builds upon features the organism already possesses and proceeds on the basis of random variation among offspring. Darwin knew that his theory carried a heavy burden:

“If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down,” he wrote in Origin of Species.

Indivisibly complex issue

Such a complex organ would be an example of an “irreducibly complex system” — composed of multiple parts, ordered in such a way that the entire system would cease to function if any one part were removed. Man-made examples would include mousetraps and watches. If any part of the mechanism is missing, it simply does not work. Such systems are obviously designed, because it is inconceivable that a chance arrangement of parts could have produced them.

Irreducibly complex biological systems — if they exist — would present a serious problem to the Darwinian theory of evolution by natural selection. There does not seem to be any plausible way in which such systems could gradually evolve by a series of accidental modifications.

It is logically possible, of course, that such a system could gradually be produced by accidental modifications down through the generations, until at last an organism has a functioning irreducibly complex system in place. But natural selection would quickly select against a complex non-functioning mechanism in an organism, as its existence would mean a useless drain of energy — either the entire system works, or it is a useless burden.

It is safe to say that all the major scientific attacks on Darwin’s theory of evolution have centered on the possible existence of these irreducibly complex biological systems.

Biochemist Michael Behe has launched the most recent and most sophisticated attack on Darwin’s theory by arguing that at the level of the cell, we find irreducible complexity. In his book Darwin’s Black Box he maintains that several features of the cell — such as mechanisms for moving and clotting blood — are irreducibly complex, and so they defy any attempts to explain them in terms of gradual evolution operating on random variation.

Behe goes even further. After an extensive review of the scientific literature, he chided the scientific community for not even attempting a detailed explanation of how these complex cellular mechanisms could have evolved by natural selection:

“No one at Harvard University, no one at the National Institutes of Health, no member of the National Academy of Sciences, no Nobel prize winner — no one at all can give a detailed account of how the cilium, or vision, or blood clotting, or any complex biochemical process might have developed in a Darwinian fashion. But all these things got here somehow: if not in a Darwinian fashion, then how?” he wrote.

Behe’s accusation that no explanation is possible is, by itself, a serious charge. And this is not the first rational attack on Darwin’s theory. Darwin himself knew nothing about genes, and for him the cell was merely a black box — a device whose inner workings were mysterious. But in 1966 a group of leading mathematicians and evolutionary biologists held a symposium at the Wistar Institute in Philadelphia, at which the mathematicians claimed that there has not been sufficient time for the number of genetic mutations needed for eyes to develop. However, some mathematical biologists disagree, arguing that we simply do not have the information needed to accurately calculate the probability that eyes developed.

Not specifically Christian

Nevertheless, the question remains that if Behe’s criticism is rational, why is there such vehement opposition from mainstream scientists against teaching intelligent design in school? Part of the reason is the religious agenda of some of the proponents of intelligent design. They see intelligent design as supporting their religious viewpoint, even if they are not, strictly speaking, creationists. Opponents view the teaching of intelligent design with the suspicion that it is just another attempt to smuggle religion back into the classroom.

But, it is important to remember that intelligent design does not really support any particular religion. In its simplest form, the argument is that billions of years ago, someone of unknown identity designed the first cell or cells on earth that already contained all information necessary to produce descendant organisms.

This may seem far-fetched, but in fairness it should be pointed out that Francis Crick, co-discoverer of the structure of the DNA molecule, thinks that life on earth may have begun when aliens from another planet seeded our planet with spores. It is but a small step to think that an advanced civilization on another world might design an artificial cell from scratch. An agreement that cells may have been designed does not imply that the designer was necessarily God. Using the analogy of a watch, if we find a watch lying on a beach, we may conclude the watch was designed, but that does not imply that there was only one designer, that the designer is all-powerful or that the designer still lives.

Proponents of intelligent design may be wrong in thinking that the theory supports their particular religious beliefs. They may be closer to the truth when they argue that the reason intelligent design is resisted by most scientists is that today Darwinian theory functions more as an ideology than as a scientific hypothesis. Scientists should remember that while biological evolution may be a historical fact, Darwin’s theory is just that — a hypothetical explanation of how biological systems developed.

As the celebrated philosopher Karl Popper argued, what separates scientific theories from ideology or philosophy is testability. Scientific theories are theories that are capable of being tested by experiment or observation. In other words, they are only held tentatively, as approximations to the truth, not as truth itself. Newtonian physics was at one time held to be completely correct until relativity and quantum mechanics showed that it was not correct, but merely an excellent approximation to the truth. By the same token, relativity and quantum mechanics could one day both be replaced with an even better approximation to the truth.

Darwin realized that his theory would be at least partly refuted, “if it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications.”

Michael Behe claims to have discovered such organs at the level of the cell. If his arguments are ignored or ridiculed, then that is evidence that Darwinism functions more as an ideology than as a scientific theory.

The legitimate source of controversy is whether or not all life can be explained as a result of chance and natural selection. Many modern neo-Darwinians simply dismiss the theory of intelligent design as religious propaganda, but Darwin himself was modest and open-minded regarding the idea of design.

In correspondence with Asa Gray of Harvard University one year after Origin of Species was published, Darwin wrote regarding design:

“I am conscious that I am in an utterly hopeless muddle. I cannot think that the world, as we see it, is the result of chance, and yet I cannot look at each separate thing as the result of Design.”

A year later he wrote to Gray:

“With respect to Design, I feel more inclined to show a white flag than to fire . . . [a] shot . . . . You say that you are in a haze; I am in a thick mud . . . yet I cannot keep out of the question.”

So, why teach the theory of intelligent design in biology classes? Well, as long as the theory is kept apart from the teaching of religion, and as long as it is stressed that intelligent design is much more controversial and less well-established than Darwin’s theory, I can think of four good reasons. First, it can be used to illustrate the nature of science and the difference between scientific theories, religious dogma, philosophy and ideology. Second, teaching this controversy as an aside adds interest to science classes. Third, it exposes students to a controversy they will likely encounter again. Why not prepare them for it as well as we can? And finally, it may possibly be true.