Intelligent Design: Is it a theory?

What is Intelligent Design?

According to a recent CBS poll, 55% of the American public does not believe in evolution. Many of these people want ``intelligent design'', a form of creationism, to be taught in schools. In some states, school boards have tried to be politically correct, and forced textbooks to issue disclaimers saying that "evolution is a theory and not the only possible theory about the origin of the species." Creationists have even managed to get a paper on intelligent design published in an obscure scientific journal called the Proceedings of the Biological Society of Washington, which is published by the Smithsonian's National Museum of Natural History.

What is this all about? Is intelligent design really an alternative to Darwinian evolution? Is it a valid scientific theory? As scientists we must remain open to all new ideas, no matter how bizarre. Many scientists have strong religious beliefs, and most appreciate that religion plays a vital role in society. At the same time, if intelligent design is not a valid scientific theory we should be honest and say so.

Virtually no practicing biological scientist believes in creationism. To my colleagues, it may seem that I am beating a dead horse, and that even mentioning creationism gives it more credibility than it deserves. But students may not be aware of this. If students go through the educational system not knowing the difference between theory and wishful thinking, we are doing them a grave disservice. Scientists should also struggle against the attacks on science, whether they come from fundamentalists on the Right who believe that God created the species in their final form, or from relativists on the Left who believe there's no such thing as truth. Not doing so would be to encourage the spread of scientific illiteracy. In this article, I will discuss why intelligent design is not a valid theory.

Is it possible to identify intelligent design?

We must first ask, is it even possible for evidence to exist that could point to intelligent design? The answer is clearly yes. One could imagine, for example, something in our DNA sequence, such as an image resembling the Voyager plaque, that unambiguously does not belong in a DNA sequence. If a picture of two naked beings waving their tentacles at us were found in our DNA sequence, someone would have had to have put it there.

The fictional TV show Star Trek: Next Generation even had an episode where such a thing was found. After much travail, much use of their tachyon emitters, and many spectacular explosions, the message turned out to be a rather dull speech by a long-dead race of androgynous aliens. These aliens had been so incredibly boring that they died out millions of years ago. Too bad. They would have been perfect candidates for membership in the United Federation of Planets.

Another example would be if we found a trademark or other message indicating the use of technology, such as the words "Made in Taiwan" in our DNA or printed on our cells. It goes without saying that if a signature in our DNA sequence had been found, we would probably have heard about it by now.

Sometimes creationists claim that the complex machinery of the human body could never have evolved spontaneously. This argument is dressed up by saying that biochemical pathways are "irreducibly complex" and therefore couldn't have evolved. Could one argue, as creationists do, that finding some feature in biology that looks irreducibly complex would be evidence of intelligent design? No. The idea that something can be "irreducibly complex" is meaningless. Complex things can always be broken down or assembled from parts. It is the definition of complexity. In biology, body parts often take on entirely new functions that would have been hard for Nature to create from nothing.

When creationists say something is "irreducibly complex" what they really mean is that they can't explain it. Thus, we can restate the argument this way:

I don't know how this feature came about. Therefore someone intelligent must have created it.

Stated this way, it's clear that the argument is logically invalid. One's lack of knowledge tells us nothing about the subject of one's ignorance. In this argument, one is arguing that because one is ignorant, therefore a Supreme Being, extraterrestrials, or whatever, must have created mankind. While the premise--that one is ignorant--might be true, the argument is a non-sequitur. It simply does not follow. In order to prove that someone intelligent built us, much more is needed than to say you can't think of any other explanation. You need to prove that this someone exists, and that this someone actually acted. Otherwise, you might as well say

I don't know how this feature came about. Therefore, flying saucers created it.

So the question really is, how could you prove that something was made and didn't evolve? How do you prove that something is intelligent? This is not easy. Computer programs have been devised that closely mimic the way psychiatrists talk, for example. Since computer programs are not intelligent, this obviously says nothing good about psychiatrists.

As an example, let's ask, "How do we know that televisions were made and did not evolve?" The answer is that we can go to a television factory and watch them being designed and built. We can meet the people who build them and read what they wrote. We don't argue that they couldn't have evolved. This would be proving a negative, which is impossible. (In fact, televisions do evolve in a sense, as engineers refine their designs. This shows that we need to be careful about how we use terms like evolution, which has multiple meanings.)

But perhaps this is an bad example. After all, there is no evidence of intelligence in TV programming despite the fact that we know that it was designed by somebody.

Philosophers tell us that the one unique thing that all conscious beings possess is a concept of self. A person has "reflexive" consciousness--that is, he or she knows that they exist. If some evidence of reflexive consciousness were found as part of our bodies, it would prove that something intelligent made us. For example, we might find the Voyager plaque mentioned earlier, or the words "Made in Taiwan" at the end of every piece of DNA. This would be evidence that someone was aware that they were making something, and they were aware they were in a particular place--in this case, a factory in Taiwan. Like the Voyager self-portrait, it is unequivocal proof that the artist is conscious of their existence. It goes without saying that no rational creationist has ever claimed to find this type of evidence.

Without some evidence of an entity possessing reflexive consciousness, we cannot claim that humans were created by an intelligent entity, whether that entity is a Supreme Being or an extraterrestrial. It is simply not enough to say that because something is fantastically well-organized and complex, someone must have created it.

Creationists are not alone in subscribing to this fallacy. Some people in the SETI program once proposed that aliens could prove their existence by sending us a sequence of prime numbers on a radio frequency. Since no known natural process can generate prime numbers, it was thought, this would be evidence of intelligence. However, this argument is also fallacious. Such a signal would be well worth investigating, but it is not by itself proof of intelligence.

Is intelligent design a scientific theory?

By now it should be clear that intelligent design is not a viable scientific theory. Let's discuss some of the reasons:

  1. It doesn't explain how the species evolved or why they are in their present form. It just says that someone built them for an unknown reason. There is no explanation of how or why, because the creator's will is unknowable. However, this also means that intelligent design can't explain anything, and therefore it can't be a theory.
  2. It doesn't make a unique prediction. Creationists say that something (i.e., a supernatural being) invented us. But one could just as easily argue from the intelligent design concept that aliens in flying saucers, giant talking rabbits, or giant Orange Smoothies invented us.
  3. And finally, there are mountains of evidence against it. We can observe mutations taking place. We know without any doubt that genetic lineages change over time due to selection, natural and otherwise. We know the mechanism by which this happens, down to the very molecule. We can see overwhelming evidence for evolution in the fossil record. Clearly, evolution is a viable theory, even if it does not explain everything in perfect detail. But intelligent design is not, because there is not a shred of evidence for it. There are only "things that we cannot understand".

    Creationists sometimes try to get around this by acknowledging that humans were created by evolution, but that some divine being intervened at some point and directed the outcome to the present form. This version of creationism usually admits that species were formed primarily by natural selection, but supposes that an external influence played some role. For example, the creator could have caused an earthquake to occur at a critical moment, or two critical individuals to meet by chance. Unfortunately, this version of creationism also is not a theory, because there is no known way to test this hypothesis. That is, there is no conceivable evidence, short of finding and asking the creator, that could prove this type of outside intervention.

    Related to this is the question of free will. If some deity controlled everything that happens, there would be no free will. Christianity has had greater difficulty than other religions in dealing with this problem. However, discussing this would get us into theological issues.

Typical of the arguments made by creationists is the question of the bombardier beetle. This insect has a small chamber where it secretes a mixture of two caustic chemicals, hydrogen peroxide and hydroquinone. At a critical moment, the beetle adds the enzyme catalase, which causes the two chemicals to react and reach a temperature near the boiling point of water. It then squirts this nasty mixture at its enemy. Creationists argue that such a thing could never have evolved because there are no intermediate steps. Any such intermediate steps, such as making a chamber with hydroquinone only, they argue, would be useless to the beetle.

In fact, the real argument is that creationists do not know what those intermediate steps are, and hence conclude that they don't or can't exist. Once again, it is the invalid "argument from ignorance". The existence of the bombardier beetle is in no way an argument for intelligent design. The same is true for the other similar examples put forth by creationists. These and other specific claims made by creationists have been refuted many times (for example, in this article in Skeptic Magazine).

If there was evolution, why are there still monkeys?

This question, shocking in the depths of its lack of basic understanding of biology, is sometimes still asked by creationists. It illustrates a major problem with education in this country. Our educational system is not providing basic information about science to our children. If people are to make sensible decisions about what gets into the textbooks, they need accurate information about the subject matter.

The argument fits into the category of an "irrelevant misdirection". It presupposes that there are only two possibilities, and that if the theory of evolution could be shown to be false, then intelligent design must be true. Unfortunately for creationists, this is not the case. Even if evolution were somehow shown to be false, it would not mean that intelligent design was true. Many other theories were proposed in the 19th century that tried to explain how the species evolved. These theories, along with creationism, were discarded because they were incompatible with the evidence. But there could be others that explain the facts better.

Just for the record, evolution does not say that humans evolved from monkeys. Both humans and monkeys evolved from a common ancestor. That is why there are still monkeys. There are literally tons of evidence for the evolution of species from common ancestors in the fossil record and in their DNA sequences.

Physical constants of the universe

Sometimes it is said that physical constants, like Planck's constant h or the gravitational constant G, are too finely balanced to be the result of chance. It is said that if one of these constants had been different by some incredibly minute fraction, that life could not exist, and that therefore someone must have created them. What about this argument?

Even physicists sometimes make this statement, without realizing that it is nonsensical. In fact, we have no idea why the physical constants have their current values, whether is is possible for them to have different values, or what type of life would exist if they were different. For all we know, there could be a mathematical reason why the speed of light must be 299,792,458 meters/second and Planck's constant must be 6.62606876 x 10-34Joule-sec, just as there is a mathematical reason the ratio of the circumference of a circle to its diameter must be the number π (pi). Perhaps string theory or some other theory will provide an explanation. But arguing that these constants were chosen by a Supreme Being to make life possible is a bit like saying, ``What if pi were 87 1/2 instead of 3.141592653589793238462643? Life as we know it would not exist!'' It may or may not be true that life would not exist. At the very least, circles would look very funny. But the question is ridiculous. It's no different from saying, ``What if circles were square?''.

The argument that God must have set these numbers is another example of the ``God of the gaps'' concept, in which the current gaps in our scientific understanding, whatever they happen to be, are supposed to be explainable only by divine intervention. Because science progresses, these gaps are not a good place for a deity to be. (At least, if I were a deity, I certainly wouldn't want to be in a place that is constantly shrinking.)

And what about pi anyway? Maybe a Supreme Being set pi equal to 3.14159 and set 1+1 equal to 2? Or as the ancient Gnostics would say, maybe a Supreme Being created the principle of numbers and the concept of roundness. Sure, it is possible. But how would you prove it?

Physicists are often the main culprit here. Sometimes physicists get all mushy about mathematics, and start raving about what a miracle it is that the physical world can be described by mathematics. They forget that the field of physics is defined as the science of things that can be analyzed mathematically. They also forget about mathematical abominations like renormalization. When physicists, in their urge to inspire awe and wonder, imply that something seems magical and unexplainable, it only invites misinterpretation by creationists.

Those who base their religious faith on some unexplained natural phenomenon risk having their faith thrown into a crisis when an explanation of the phenomenon is eventually found. Not only would the discovery undermine their religious beliefs, the believers would also be unable to share in the excitement of the discovery. When scientists eventually find a naturalistic explanation for the Big Bang, for example, the same creationists who spend their hours denigrating Charles Darwin will undoubtedly turn their wrath to the cosmologists who undermined their religious beliefs about the creation of the universe. How much better it would be if their beliefs were founded on authentic religious experience instead of contrived logical arguments!

Design flaws in the human body

Any biologist will also tell you that there are a number of features in nature that no rational being would put there. If some all-knowing, perfect deity created us, the deity must have been having a really bad hair day. No designer worthy of the name would build something this way, yet stupid designs can easily be explained by evolution, which gets stuck in "local minima" just as the theory predicts. I will just mention two of these examples.

Optic nerve Unlike the retinas of octopuses and squids, our optic nerve goes right through the middle of the retina, creating a large blind spot. The reason for this is that our photoreceptor cells (the rods and cones) are aimed backward, away from the light source. Other species, like the squid, have a much more "intelligent" arrangement, with the retina in front of the optic nerve, which not only avoids creating the blind spot but gives their eyes better sensitivity.

Rubisco Another example is RibuloseBisPhosphate Carboxylase/Oxygenase, or Rubisco, an enzyme in plants that attaches atmospheric carbon dioxide (CO2) to a sugar molecule called ribulose 1,5-bisphosphate. This is a critical step in photosynthesis. However, the enzyme is so inefficient that in order to survive, plants must make so much of this Rubisco protein that up to 40% of the proteins in plants consists of Rubisco.

Because evolution got trapped in a local minimum back when oxygen was a very minor component of the atmosphere, Rubisco works even more slowly than it should because the Rubisco molecule also captures oxygen (O2) in what is called an oxygenase reaction. The oxygenase reaction reduces potential plant productivity by an additional 30 percent.

There are many more examples, including the design of the trachea, which needlessly allows choking, and diseases like sickle-cell anemia, which is a painful genetic disease caused by a mutation in the hemoglobin molecule, which carries oxygen to the tissues. The sickle-cell anemia gene is not eliminated from the gene pool because it provides protection against malaria. An intelligent creator would have found a better way.

Why not just teach creationism in the schools alongside evolution, just to be fair?

With the possible exception of a few extremist civil libertarian groups, most people would be unconcerned if creationism were taught in the schools as religion. But if creationism, an unproven idea that is not accepted by most scientists, were taught as science, where would it end? Even a brief tour on the Internet would show that there are hundreds of crank theories out there, many of them utterly crazy--that the Earth is hollow and the inside is populated by Martians, that aliens from outer space built the great pyramids, that Susan Sarandon and Sean Penn are good actors, to name only a few--that soon there would be no time left to teach what is actually known to be true about the universe.

New ideas will always be accepted in science if evidence is found that supports them. So far, creationism has not provided any evidence that points to a creator--only arguments. And it's been demonstrated many times that these arguments, as appealing as they might seem to some religious people, are logically invalid.

Notice, however, that I did not say that ``intelligent design'' is false. Personally, I happen to think that it is false; but in science, what I or anyone else believe is irrelevant. In order for something to be accepted as scientifically true, you have to be able to answer the question, ``How do you know?''. If you can't answer that question, you don't have science. You have religion, or maybe something else, like art appreciation or economics.


Religion has an important role to play in society. Religion is first and foremost a way for people to deal with death. Without an appreciation of what death is, we cannot appreciate life. Our lives become spiritually empty and aimless. Christianity is also an important part of our culture. At the same time, we shouldn't try to mix religion and science, or allow ourselves to believe in something solely because it makes us feel happier. Religions, like tree finches, must evolve or they will become extinct. If religions try to base their belief on illogical arguments, or make assertions about the natural world that conflict with the evidence of our senses, they will only hasten their own decline. And that is bad for everyone.