Nathan Lents: Bad Design of the Eye?


(S. Joshua Swamidass) #25

So in what sense are they poorly designed precisely? I"m not asking for a repetition of what you have written. I’m just wondering why you say this is poorly designed? It sounds like it might be optimally designed from a less than optimal starting point. That is not semantically equivalent to “bad design.”

Also, there may be some big advantages to having the retina wired this way. Let me offer a few alternate hypotheses.

  1. It is not clear that this “backward” configuration actually is less efficient at capturing light. What papers are their that demonstrate this? The lengths involved here are are tiny, and cells are transparent (except for the pigment). Do you have any references that can demonstrate that this is suboptimal for collecting light? How was that experimentally tested?

  2. One possible advantages of requiring light to go through cell bodies (the backwards wiring) before collection is that it enables evolution to tune the wavelengths of cells by putting different pigments in cellular vesicles. This is much more important for land vertebrates than water-bound octopi, who do not have as a wide a range of wavelengths to perceive. Given how important vision is to, for example, mammals. It is not clear that the octopi eye could reach the same level of tuning required for colored site as we see in mammals.

  3. I understand your hypothesis, that the “verted” retinal can pack tightly, but it is not clear to me why a mammal retinal couldn’t be packed tight. Can you show me the papers demonstrating that this is the case? Also, the tapetum lucidum is an another interesting case where the biophysics is really important to understand. It very well may be possible that this is an easy way of increasing the sensitivity of the “backwards” retina, but not the octopi retina, which would then explain why the more tight packing of vertebrate eyes is not common.

I"m not trying to be difficult here. I think some of what you have written are reasonable hypotheses. However, that is far from certain. I’m not sure if they have been demonstrate correct over alternate hypothesis yet. Do you know if they have been? What citations do you have?

I want to be clear that I am NOT calling you out @NLENTS, so please don’t take this personally. I’m just not sure that the string of facts here are actually known to be true scientifically. There are alternate hypotheses, and it is not clear which hypothesis is correct. In each case, it might be:

  1. You actually are correct, and this is actually demonstrated in the literature.

  2. You may or may not be correct, but it is not demonstrated in the literature.

  3. You are just not correct, and the opposite is demonstrated in the literature.

The challenging problem, for me, as a scientist, is that this ends up being a very complicated morass to sort out. the argument ends up raising far more questions than it answers, almost like a Gish Gallop. For the argument to work, we have to be dismissive of these questions. However, science doesn’t work that way. We care about those questions, and we know our intuitions on how they will be answered are often wrong.

That is why calling them “Mysteries” is, in my view, far more accurate and true to science.

(S. Joshua Swamidass) #26

I’m reminded here that I am neither a theologian or philosopher. What do some of those of relevant expertise think of the theology of the “bad design” argument? @jongarvey @deuteroKJ @Philosurfer

(S. Joshua Swamidass) #27

(Dan Eastwood) #28

This is can be effective sometimes, assuming their theory and following it to the necessary consequences. It’s great for defense lawyers because the prosecution is required to make its case. But this is not always the situation for the ID advocate/Creationist, who can just ignore those consequences and move on to another claim. To use this effectively requires specific claims from ID, and “too complex to evolve” is not specific about what is complex or what was designed.

This is interesting, because countering (for example) a YEC argument with a theological argument is often effective because it reframes their argument to what it is (theology). If I do the same versus an ID argument then I get accused of not being scientific. So either I’m not being sneaky enough in disguising my theological arguments against ID, or maybe it is just a bad argument.

I like @NLENTS comments about GULO. Why should a designer assemble parts well enough to work, but allow harmful flaws to remain? It the eye is designed, then why leave GULO broken, bad knees, bad back, and a host of other design flaws?

(S. Joshua Swamidass) #29

Remember how I answered this? I suggested occurs because God designed by a process of common descent. Though the GLUO is not used for making Vitamin C any more, in the past it did have a purpose. You cannot presume God did not design us by an evolutionary process. An argument for common descent is not an argument against design.

ID is more difficult because…shall we say “doublespeak?”

Though, in recent years it has become easier. I think they have given up on the original plan of using “Intelligent Designer” as an end run around methodological naturalism. Now, it seems many prefer to just get rid of methodological naturalism.

What has been most helpful for continuing the conversation is to ask them for a mathematical model of design. They are in a difficult bind if we make the legitimate request to produce a mathematical model of design that explains features currently explained by common descent, with at least as much mathematical rigor. As it is, the vast majority of patterns we see in biology are explained by common descent. Until we have a mathematical alternative, common descent is the conclusion of science, regardless of methodological naturalism.

For the longest time, there was nothing coming out of ID on this. There is, now, an example of one model from @Winston_Ewert. That is a good step for them, though it is preliminary results at best. It is hard to imagine it extending to all the patterns.

With ID, engaging the theology has been just as important as laying down what they need to do to make their case. To their credit, this seems to be taken seriously by the best of them (@Winston_Ewert and @Agauger). To their detriment, others in their camp tend to oversell and puff at every turn. This is not helping their scientific case. I am hopeful this fact is going to sink in sometime in the future.

(Dan Eastwood) #30

I do. I was grasping for a theological argument that was not overtly scientific. A better argument is that science does not deal with the supernatural, and conversely it should not be possible to know God by means of science. Until ID explicitly rules out supernatural cause, it is making a claim that is “bad theology”. (according to the theologians I have discussed this with.)


I rule out supernatural causes. God’s causes in the natural world are natural causes. Besides, there is no scientific way to distinguish between “natural causes” and “supernatural causes.”

Am I permitted to post in this thread?

(Dan Eastwood) #32

I will move these to side comments if SJS asks me, or if we get too long winded. :slight_smile:

It’s not enough just to say that; it needs to be demonstrated. This requires material evidence to back the claim. In the case of human design we do not infer the existence of humans; we already know humans exist (we are the material evidence). For an Intelligent Designer, the existence of such a designer can only be assumed, making it a supernatural claim.

In this case, you are clearly making a theological claim (God’s causes are natural causes). That is OK, because you aren’t pretending to make a material claim.