PBS Evolution A Critical Review

“Evolution” Series Claim on Eye Evolution More Fiction than Fact


SEATTLE–Viewers of the WGBH / Clear Blue Sky series “Evolution” will be given the false impression that a Swedish scientist has proven how evolution could produce the human eye in less than half a million years.

“Zoologist Dan-Erik Nilsson has developed models to show how a primitive eye spot could evolve through indeterminate stages to become a complex human-like eye in less than half a million years,” the narrator of “Evolution” tells viewers. As the narrator continues to describe Nilsson’s research, Nilsson is shown working diligently at his computer. The implication is that he has created a computer “model” to simulate how an unguided process of natural selection could produce the eye. Nilsson is shown saying that his research shows “exactly the way eye evolution must proceed.”

In reality, neither Nilsson nor anyone else has thus far created a computer model for eye evolution. Furthermore, according to Discovery Institute Senior Fellow David Berlinski, the crude calculations that have been published by Nilsson are not such a model. Berlinski holds a Ph.D. in Philosophy from Princeton University and was a fellow of the faculty in mathematics and a postdoctoral fellow in biology at Columbia University. He is the acclaimed author of such books as “A Tour of the Calculus” (Pantheon, 1996) and “The Advent of the Algorithm” (Harcourt, 2000) and “Newton’s Gift” (Free Press 2001). He lives in Paris.

“In 1994, Nilsson and Susanne Pelger published an article called, ‘A pessimistic estimate of the time required for an eye to evolve,'” says Berlinski. “The article contained a couple of back-of-the-envelope calculations that if we assume this, and we assume that, we’ll get an eye in 400,000 generations. There was absolutely nothing by the way of supporting evidence or documentation. Nothing. You could have said ‘800,000 generations,’ or you could have said 2 zillion years. All of that would have been equally supported by the evidence Nilsson and Pelger actually presented.”

“Even if we were to accept everything they say–counting mere calculations as if they were a computer model, and a half million years’ evolution was sufficient–all they would have demonstrated applies only to the formation of an eyeBALL, not to a complete eye. An eye is an organ that accounts for what an organism sees or can see; it is far more than an eyeball. PBS at best is guilty of a wild exaggeration.’

Since Nilsson and Pelger’s article was published, it has been widely–but erroneously–reported that their conclusions were based on a computer model. Berlinski calls this claim “an urban myth.” “

The Nilsson-Pelger paper is interesting but very minimal. We wrote to Nilsson and he quite freely acknowledges that his article on eye evolution was not based on any computer model,” says Jay Richards, also a Discovery Institute Senior Fellow. “Nilsson says that he is now trying to create such a computer model, but it still needs a lot of work.”

“PBS is misleading viewers when it presents Nilsson’s conjectures as if they were established science,” Richards adds. “At a minimum, PBS should make clear to viewers that Nilsson’s conclusions are not based on computer models at all, and it should acknowledge that his work is highly speculative.”

Founded in 1990, Discovery Institute is a non-profit, non-partisan public policy center for national and international affairs. Its programs deal with a range of issues, including science, technology, regional development, environment, and defense. More information about the Institute and its activities can be found at www.discovery.org.

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