First, Dembski mentioned a paper (I believe it is
this paper) to counter the argument that the placement of the optic nerve in front of the retina is poor design. The paper talks about the way in which the Müller cells, in the front of the retina, serve as an optical filter that improves vision. I'm not sure how this relates to the placement of the optic nerve. Are the Müller cells, in some way, part of the optic nerve and if the optic nerve were behind the retina these cells wouldn't be in front of it? Or, is Dembski arguing that there would be less oxygen available to the retinal cells if the optic nerve were behind the retina (the paper does not make this point)? I'm wondering because a standard trick of creationists is to claim some new fact changes the way things have to be viewed - in this case Dembski is arguing that the optic nerve in front of the retina is an advantageous design. Does anyone know if that's true? I don't believe the paper explicitly talks about the optic nerve - but if the Müller cells are a part of this nerve, then the paper agrees with him.
The abstract from the paper:
Although biological cells are mostly transparent, they are phase objects that differ in shape and refractive index. Any image that is projected through layers of randomly oriented cells will normally be distorted by refraction, reflection, and scattering. Counterintuitively, the retina of the vertebrate eye is inverted with respect to its optical function and light must pass through several tissue layers before reaching the light-detecting photoreceptor cells. Here we report on the specific optical properties of glial cells present in the retina, which might contribute to optimize this apparently unfavorable situation. We investigated intact retinal tissue and individual Müller cells, which are radial glial cells spanning the entire retinal thickness. Müller cells have an extended funnel shape, a higher refractive index than their surrounding tissue, and are oriented along the direction of light propagation. Transmission and reflection confocal microscopy of retinal tissue in vitro and in vivo showed that these cells provide a low-scattering passage for light from the retinal surface to the photoreceptor cells. Using a modified dual-beam laser trap we could also demonstrate that individual Müller cells act as optical fibers. Furthermore, their parallel array in the retina is reminiscent of fiberoptic plates used for low-distortion image transfer. Thus, Müller cells seem to mediate the image transfer through the vertebrate retina with minimal distortion and low loss. This finding elucidates a fundamental feature of the inverted retina as an optical system and ascribes a new function to glial cells.
the rest of the paper ...My second thought is on the question of morality as it was raised in the debate. My interpretation of Dembski's moral claim is that "it's good if God says it's good." IOW, morality is completely determined by God, there is no other standard. He then claims that atheists have no basis for morality.
I agree with the beginning of Hitchens response - morality comes from the evolutionary process. But then he says that morality is determined by the Socratic method. I think he's completely wrong there.
I agree that morality is determined by the evolutionary process. Whatever cultures survived, then, ipso facto, their morality was valid. But, this does make morality somewhat arbitrary - we should do what we feel is right because our innate feeling tend to be correct; but, we don't always know what behaviors lead to a better probability of survival.
This raises difficult issues about in-group/out-group behavior. My take on this is that cultural/moral behaviors of other groups, behaviors that don't directly impact the survival of our group, are acceptable. The more different behaviors that human groups have, the better over-all chance for the survival of the species.
I think Hitchens needs to work on his position on morality. If morality is evolutionarily based, then it does not come from the Socratic method. The Socratic method can make adjustments to our behavior, but it really cannot dictate visceral feelings. And, to my mind, morality is largely based on visceral feelings.