An Idiotic Eye

Attention: open in a new window. PDFPrintE-mail

An Idiotic Eye: Richard Dawkins asserts the vertebrate eye is particularly badly designed. He first condemns the eye for only having clear vision in the fovea (the central region of the total visual field for each eye), and therefore we need to constantly move the eyes and use image processing software in the brain to see a whole scene clearly. He then directs his attention to the retina – the light sensitive layer at the back of the eye that converts light into electrical signals and sends them to the brain.
According to Dawkins “the retina is back to front”. He compares the eye to a digital camera with an array of light sensitive photocells and then explains: “… suppose I tell you that the eye’s photocells are pointing backwards, away from the scene being looked at. The “wires” connecting the photocells to the brain run all over the surface of the retina, so the light has to pass through a carpet of massed wires before they hit the photocells. That doesn’t make sense – and it even gets worse. One of the consequences of the photocells pointing backwards is that the wires that carry their data somehow have to pass through the retina and back to the brain. What they do, in the vertebrate eye, is all converge on a particular hole in the retina, where they dive through it. The hole filled with nerves is called the blind spot, because it is blind, but ‘spot’ is too flattering, for it is quite large, more like a blind patch, which again doesn’t actually inconvenience us such because of the ‘automatic Photoshop’ software in the brain. Once again, send it back, is not just bad design, it’s the design of a complete idiot.”
Richard Dawkins, The Greatest Show on Earth, Bantam Press, 2009, pp353-354, emphasis in original
Editorial Comment: The “back to front” retina has been a favourite topic for sceptics pouring scorn on creationists for years, but it is also the best example of fools being too quick to denigrate things that we do not yet understand and need further research. Recent research on the retina show the retina is very well designed.
In 2007 a group of German scientists studied Muller cells – the cylindrical support cells that span the layers of cells in the retina. They found Muller cells acted like optical fibres conveying light from the front of the retina to the back where the photocells are. (See “Human Eyes are Badly Designed” in this Fact File). Now, a further study on the Muller cells show that they re-focus different coloured light that has been split up as it passes through the front of the eye. Amichai Labin and Erez Ribak of the Technion-Israel Institute of Technology in Haifa, who carried out this study, concluded: “The retina is revealed as an optimal structure designed for improving the sharpness of images.” (Physical Review Letters, vol. 104, p158102, 16 April 2010.)
In spite of this, the editors of New Scientist, who commented on this latest retina discovery, were determined not to give in, and admit the retina is well designed, so they wrote an editorial claiming: “Rather than provide evidence in support of intelligent design, the new work is actually yet another example of evolution's extraordinary ability to create workaround solutions to problems arising from earlier iterations” (New Scientist, 6 May 2010, p3). They go on to claim the eye is still poorly designed because it has a blind spot – the structure Dawkins described as “the design of a complete idiot”. However, as Dawkins himself admits, the blind spot (calling it a “patch” is exaggerating its size) is no inconvenience to us because the brain processes the information, in a similar way to using an image editing computer program to fill in the gaps. The brain is able to do this because we have two eyes which are constantly moving (even when we think we are keeping them still) so there is plenty of information to fill the hole in the visual field. This movement is now recognised as good design as it makes maximum use of the fovea, and it doesn’t matter that the periphery does not focus as well. This constant movement, and the brain’s control of it, is now being used as a model for scientists to develop better machine vision.
Dawkins should also consider the logical deduction from his correlation of the eye and brain with digital cameras (artificial eyes) which do not make themselves, and image editing software (artificial brains) which never write or make themselves. Furthermore, software is never written by the digital camera that captures the images, or by the computer that runs the image editing program. It was written by a pre-existing creative intelligence, outside the camera and computer, who knows about images and computer programs. If Dawkins doesn’t come to terms with this reality, one day he will have to explain to the Creator who gave him eyes better than a digital camera, and a brain with better image editing software than Photoshop, why he called Him “a complete idiot.” (Ref. optics, neurology, atheism)
Evidence News, 26 May 2010

q_and_a2
crc_youtube
outdoor_museum_panel
free_audio2