'Intelligent design' is dangerous folly

Published on Saturday 27 August 2005 00:00

EARLIER this month, much to the joy of the evangelical Christians, the US president, George Bush, placed his weight behind a proposal to include the theory of "intelligent design" in the American school biology curriculum.

ID argues that the natural world is so complex it could only have come to be had there been some unseen intelligence behind it to design it that way. In contrast, the theory of evolution - which, of course, eschews any such suggestion - is seen as inadequate, and full of intellectual as well as factual holes. ID is not, in fact, an especially novel idea: it dates back to the English theologian William Paley, who, in his 1802 book Natural Theology, used the perfection of nature as an argument for the existence of God (the "grand designer").

In the words of one of ID's leading lights, the biochemist Michael Behe, from Lehigh University in Bethlehem, Pennsylvania, something as complex as a living cell could not have evolved by a series of small steps in which its elements were gradually assembled one by one: a cell without its organelles, for example, would be about as functional as a mousetrap before the spring was added. The gauntlet thrown down to the evolutionists is to show that a blind process of mutations could produce the kind of complexity we see in the world around us. Failure to do so is taken as implicit support for the default position (that there must have been a designer).

To the naive, these arguments sound extremely plausible. But their plausibility rests on a state of ignorance. Take the eye, for example. Could one imagine an imperfect eye that lacked a lens: how could such an eye possibly help its owner? Well, the short answer is that there are plenty of examples of eyes of this kind in nature, and they are all perfectly functional. We need look no further than the humble mollusc to see eyes that range from simple light-sensitive clusters of cells, to lens-less eyes, to eyes with fixed lenses, to eyes with adjustable lenses hardly different from our own (in the octopus, by the way).

The problem is that most of the advocates of ID seem not to be particularly well versed in good old fashioned natural history. As a result, they are not familiar with the many everyday examples that make nonsense of their arguments. Nor, it seems, are they especially well versed what the theory of evolution actually says. A common belief among IDers is that Darwinian evolutionary theory assumes the process of evolution is a consequence of blind chance - mutations randomly producing small changes that gradually add together. Hence, the common assertion that evolution by natural selection is equivalent to claiming that a jumbo jet could be assembled from a junkyard by a whirlwind. Alas, evolution is not a random process in this sense. Mutations certainly occur at random, but the processes that select and gradually fit mutations together over time are far from random: natural selection, Darwin's great contribution, is a very directed process and can work with astonishing speed. It has taken only 100,000 years to produce the snow-white polar bear from its common ancestor with other Eurasian brown bears.

What makes all this so intriguing is why otherwise perfectly rational people with solid scientific credentials should be so enamoured of ID. It is conspicuous that most of those who espouse ID are not organismic biologists.

For the most part, they are mathematicians, biochemists, cell biologists, physicists, even philosophers - mostly people working in disciplines whose activities are largely unaffected by whether or not the theory of evolution is true. And why are they so antithetical to Darwin's theory of evolution, given that this is in fact the second most successful theory in the history of science (after quantum mechanics in physics, perhaps the most inscrutable theory ever invented)?

Failing to understand the force of natural selection and its role in evolution has had, and will have, fairly serious consequences for all of us. It has been failure to understand evolutionary processes that gave us DDT-resistant insect pests in the 1950s, drug-resistant malaria in the 1980s, and now the phenomenon of the MRSA superbug.

• Professor Robin Dunbar is based at University of Liverpool's school of biological sciences.