Mark I. Vuletic

Last updated 08 April 2011

Analysis

(i) Is the eye too perfect to have evolved?

I have discussed in a different section the claim that the eye is too perfect to have evolved.

(ii) Could eyes have evolved gradually?

 Imperfections aside, could the human eye have arisen via evolution? Creationist Scott Huse contends that "the eye would be useless unless fully developed. It either functions as an integrated whole or not at all" (Huse 1983:73). The general logic behind this kind of assertion is treated in the first part of my analysis of claims of irreducible complexity. But is there anything more specific we can say about the eye, in particular? 

(iia) Naturally, no one has observed the evolution of the eye in a laboratory because of the timescale involved, but one can look to the gradations in the present world for clues. In fact, nature displays progressions of simple to complex visual structures (Ecker 1990:65-66), such that one can see how the eye could have evolved gradually. A video from the National Center for Science Education goes through all of it simply:

For much more detail, and multiple lines of evidence, consult Lamb et al. (2007), P. Z. Myers's on-line review of that article, and the special issue of Evolution: Education and Outreach (Volume 1, Number 4) devoted to the evolution of eyes.

(iib) Paul R. Gross explains how a model by Dan Nilsson and Susanne Pelger has bolstered the case for the natural evolution of the eye by small steps:

In a 1994 theoretical paper, Nilsson and Pelger modeled one possible evolutionary pathway to the geometry of a fish-like eye from a patch of photo-responsive cells. There were already such cells—among the oldest organisms on Earth—a billion years before there were eyes. Nilsson and Pelger used pessimistic estimates of the relevant parameters (such as the intensity of selection) for their number-crunching. The point was to determine how many plausible, populational micro-steps of variation would be needed, under minimal assumptions, for very weak selection to yield a fish-like eye—and then under reasonable assumptions to convert micro-steps into generations and years. The order of magnitude answer was 350,000—a geological blink of the eye. (Gross 2003)

There has been a strange controversy about the fact that some popular writings by Richard Dawkins (e.g. 1996: 161-165) describe Nilsson's and Pelger's work as a computer simulation, when it is in fact a mathematical model. Creationists appear to be very worked up about this, but as Nilsson himself explains:

I have not considered this to be very serious, because a simulation would be a mere automation of the logic in our paper. A complete simulation is thus of moderate scientific interest, although it would be useful from an educational point of view.

The Nilsson and Pelger (1994) paper remains scientifically sound, and has not been challenged in any scientific journal with a peer review system (Nilsson 2003).

We may regret Dawkins's lack of absolute precision, but the point is in the end a mere quibble, affecting none of the substance or importance of Nilsson's and Pelger's work.

(iii) Did Darwin himself think eye evolution was hopeless?

(iiia) Creationist Shmuel Waldman writes:

In fact, Darwin himself admitted that "The eye, to this day, gives me a cold shudder," being that it's an "organ of extreme perfection." (Waldman 2005:25).

Waldman's citation for all of this is "C. Darwin (1860), in a letter to Asa Gray, in F. Darwin, ed., Life and Letters of Charles Darwin, vol. 2, London:John Murray, 1883, p. 273" (Waldman 2005:25, f4). Thanks to the Darwin Correspondence Project, it is a simple matter to check the letter. Doing so, we find that what Darwin really said was this:

The eye to this day gives me a cold shudder, but when I think of the fine known gradations, my reason tells me I ought to conquer the cold shudder. (Darwin Correspondence Project Database 2011)

Nowhere in the letter does the phrase "organ of extreme perfection" occur.  Waldman has cut out the part of the quote that is inconsistent with the case he wants to make, and has spliced in words from somewhere else, without citation.

(iiib) Creationist Scott Huse claims that "Charles Darwin acknowledged the utter inadequacy of the evolutionary theory when attempting to account for a structure such as the eye" (Huse 1983: 73). The evidence he offers for this claim is an alleged quote from Darwin:

To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical, and chromatic aberation, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree... The belief that an organ as perfect as the eye could have formed by natural selection is more than enough to stagger anyone. (Huse 1983:73)

Anyone familiar with standard creationist tactics involving "quotes from evolutionists," will wonder what the deleted material is. When we locate the source material, which happens to be from the Origin, we discover predicatable results.

First, the part before the elipses and the part after the ellipses are separated by nearly twenty pages (for reference, I am using the CRW 2004 edition). Second, there is important missing material from each part:

Immediately after "degree," Darwin goes on to say:

Yet reason tells me, that if numerous gradations of from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a pefect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. (Darwin [2004]:207-208)

This is hardly an acknowledgment of the "utter inadequacy" of evolution.

Second, the part after the ellipses has an important first word cut off (with no indication—when one introduces capitalization not present in the original text, one is supposed to put square brackets around it so the reader knows this was not the beginning of a sentence in the original), and omits material immediately after that turns the entire quote on its head. Here is the original:

Although the belief  that an organ so perfect as the eye could have been formed by natural selection is more than enough to stagger anyone; yet in the case of any organ, if we know of a long series of gradations in complexity, each good for its possessor, then, under changing conditions of life, there is no logical impossibility in the acquirement of any conceivable degree of perfection through natural selection. (Darwin [2004]:226)

Once more, Darwin's stance is revealed to be the exact opposite of the stance Huse attributes to him.

 Unfortunately, the  dishonesty and  lack of professionalism exhibited by Waldman and Huse above is not at all uncommon among creationist authors, especially when they allege to produce damaging quotes from evolutionists.

References

Darwin C. [2004.] The Origin of Species. New York: CRW.

Darwin Correspondence Project Database. [2011] http://www.darwinproject.ac.uk/entry-2701 (letter no. 2701; accessed 8 April 2011).

Dawkins R. 1996. Climbing Mount Improbable. New York: W. W. Norton & Co.

Ecker EL. 1990. Dictionary of Science and Creationism. Buffalo: Prometheus.

Futuyma DJ. 1983. Science on Trial: The Case for Evolution. New York: Pantheon.

Gross PR. 2003. A scientific scandal. www.talkreason.org/articles/blurred.cfm#scandal.

Huse SM. 1983. The Collapse of Evolution. Grand Rapids, MI: Baker.

Lamb TD, Collin SP, and Pugh EN Jr. 2007. Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup. Nat Rev Neurosci 8(12):960-76.

Nilsson D-E. 2003. Beware of Pseudo-science: a response to David Berlinski's attack on my calculation of how long it takes for an eye to evolve. www.talkreason.org/articles/blurred.cfm#lund.

Waldman S. 2005. Beyond a Reasonable Doubt: Convincing Evidence of the Truths of Judaism. Jerusalem: Feldheim.

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