A Scientist looks at Evolution versus Intelligent Design


By Paul O’Lague, Ph.D

In 1859 Charles Darwin published The Origin of Species, his theory of evolution by natural selection.
Since then our world has not been the same. Chance and necessity became the new driving force in biology. Design and purpose, parts of Aristotelian metaphysics, were no longer necessary.


The Origin of Species was an immediate success, selling out in a few weeks, and raised the shackles of proper English society. One Victorian lady upon hearing that a new theory said she was descended from apes, replied (my paraphrase),” Oh, dear, let’s hope it’s not true, but if it is, let’s hope it doesn’t become widely known.”

Today Darwin’s theory is widely known and his name is forever linked to the idea that species, including us, arise by descent with modification: descent through the blue print of deoxyribonucleic acid, DNA, and modification through random mutation.

Organisms are selected because they evolve mechanisms to survive and procreate successfully in their environment. Obviously such a god-less notion would never sit well in a world created by the gods of organized religions. In the Judaeo-Christian religion, for example, the Bible is the final arbiter of the creation of the world and its creatures.

This is ‘Creationism’, which recently has become dressed in a new pseudo-scientific cloak, called Intelligent Design (ID), which rejects evolution in favor of a grand designer and, in fact, is considered by most scientists to be nothing more than a form of ‘Neo-Creationism.’

On the other hand, Vatican II has emphasized that science is also a creation of God and thus there should be no conflict between religion and in the findings of science.

In this country with its present conservative and fundamentalist atmosphere, ID has become politicized and recently several school boards have tried to get ID taught in their public schools as a serious scientific alternative to Darwinian evolution.

However, in a well-publicized decision in Tammy Kitzmiller, et al, versus The Dover Area School district, et al, of Pennsylvania (2005) Judge John Jones concluded, after much testimony, that ”…ID is not science and the only real ID policy is in the advancement of religion.” Clearly this is a welcome vote for the separation of church and state (and religion and science), a notion originated by Jefferson. Despite such court decisions, ID continues to be pushed by certain religious and ‘scientific’ circles as a viable alternative to Darwinian evolution.

Today school children are taught the scientific method: do experiments, and collect results (facts), develop a scientific (that is falsifiable, meaning it can be proved false) theory used to explain the facts, and then test with more experiments.

One needn’t even do physical experiments to devise a theory. Einstein didn’t! He did gedanken (thought) experiments and came up with some pretty good theories. The key is to think up a testable theory that makes predictions about how the world works. Being testable also means that it takes only one experimental result (usually confirmed by others) to prove it false.

For example, my theory is that the Moon is made of green cheese. This is a scientific theory. Now for the test: I find that light reflected from the surfaces of the moon and green cheese has different spectra, i.e. different frequencies of light waves. Therefore, my theory is false.

Results in agreement with a theory continue to strengthen, but never prove, it. A theory that hasn’t been proven false continues to be useful within the edifice of science. Evolution by natural selection is such a theory and Intelligent Design is not.

But before discussing both, let’s see what is means to test a theory, especially one about evolution, a one-time event. Critics of Darwin’s theory, especially ID ones, draw a distinction between ‘origin science’ and ‘operation science.’ The latter deals with ongoing, regular operations of the natural world where repeated experiments are possible and the former with scientific questions involving singular events such as evolution and the Big Bang. IDers narrowly define science only as ‘operation science’ thus reject evolution as non-science.

However, Ernst Mayer deals with this in his book, “This is Biology” (1998). In essence, biological questions about unique occurrences such as “ Why are there no humming birds in the Old World?” or “Where did Homo sapiens originate?” cannot be answered by causal-law explanations, i.e. using logic, mathematics, or physical sciences. To study these and other similar questions, biologists must study all the known facts about a question, infer many consequences from the facts, and then try to construct a scenario to explain the facts.

In other words, the biologist constructs a historical narrative. This narrative has explanatory value because earlier events in a historical sequence often make a causal contribution to later events.

For example, much physical evidence indicates that a giant asteroid plowed into Earth at the end of the Cretaceous, killed the dinosaurs, which in turn caused the rise of the age of mammals (leading to you and me) during the Paleocene and Eocene. So the singular task of the historical narrative is to uncover causal factors that are crucial to the occurrence of later events in a historical sequence. Darwin’s theory is science in the above sense.

Furthermore, the results of many present-day molecular biological experiments on how speciation occurs and other predictions are consistent with Darwin’s historical narrative. In fact, most biologists think that the results of their experiments make sense only in light of evolution.

Even accepting the role of chance as the ultimate designer, it is quite challenging to see how it led to the riot of diversified and utterly complex biological mechanisms that exists today.

Two favorites of ID critics are the eye in mammals and lower down the evolutionary tree, the flagella of bacteria. Each consists of a multi component system (40 proteins in the flagella complex) and removing one component causes each to cease functioning. So the argument goes how can evolution select for one component (not functional) without selecting for all at once (functional), highly unlikely.

This has led IDers to the concept they call irreducible complexity, which is that certain biological systems are just too complex to have evolved naturally from simpler, or "less complete", predecessors. The concept is generally used as an argument for ‘intelligent design’ and as a counterargument (also used by creationists) against the theory of evolution.

However, they offer no way to substantiate their claim and ID makes no predictions, which may be tested. In fact it is difficult to see how ID, which posits a ‘Grand Designer’ might ever be tested. Therefore ID is not falsifiable and, as Judge John Jones concluded ID, is more akin to an idea to advance religion.

In contrast, evolution has testable answers to how complex organs and mechanisms arose. The late Stephen Gould referred to it as the 5% solution. During evolution the function of a protein may shift from playing one role to a completely new and different role. This most likely happens by the gene duplication followed by chance mutations. In that way, the protein made from ‘good’ gene still functions and the one from the duplicated ‘mutated’ gene is left to find other functions.

For example, in eye evolution, photopigments, integral parts of visual systems, may start out in energy transformation of light to chemical energy and only later become part of light detection system, which eventually joins other systems so that light now controls behavior like movement toward light. The same arguments can be brought to bear when considering the evolution of flagella or other complex biological systems.

In the end evidence that evolution through natural selection is sufficient to shape the diversity we see today is overwhelming. The universality of the triplet genetic code used by all animals implies descent with modification.

Many proteins coded by genes such as HOX genes, which specify body axes and by genes of the nervous system, for example, found in animals from flies to humans are highly conserved, meaning DNA sequences as well as amino acid sequences are very similar.

In fact, certain human genes for cell division carry out similar functions quite well when placed inside the lowly baker’s yeast.

The great recent surprise is that the newly sequenced chimp genome differs from human by 1% when protein sequences are aligned. This translated into about a two amino acid difference in an average protein.
Somewhere these differences are giving rise to the traits that make us uniquely human. Genetic variations revealed by sequencing DNA is the raw material that will help unravel human evolutionary history, not an untestable search for a Grand Designer.

The author is a Professor of Biology at UCLA, author of many papers, and member of the Southern California Federation of Scientists. This is one of a series from the SCFS written for Beachhead readers.

Posted: Tue - August 1, 2006 at 09:34 AM          

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