The Case for a Creator, Chapter 4
In the last section of his interview with Stephen Meyer, Lee Strobel brings up the dysteleological argument, asking how intelligent design can account for the faults and imperfections in the natural world that would seem to cast doubt on the wisdom or benevolence of the designer. He begins with a classic argument, the inverted retina. Quoting Ken Miller:
“We would have to wonder why an intelligent designer placed the neural wiring of the retina on the side facing the incoming light… This arrangement… produces a blind spot at the point where the wiring is pulled through the light-sensitive retina to produce the optic nerve that carries visual images to the brain.” [p.86]
Meyer waves this off, claiming (without further explanation) that this arrangement is “a tradeoff that allows the eye to process the vast amount of oxygen it needs in vertebrates” [p.87], which Strobel accepts without qualm. He admits that this arrangement produces a blind spot, but “that’s not a problem because people have two eyes and the two blind spots don’t overlap”. I’m sure the families of people killed in car accidents because they didn’t see the other car in their blind spot will be relieved to hear that.
Although Meyer doesn’t go into any more detail about what he means, I’m assuming it’s the same argument as given here by Michael Denton. But even if one accepts the creationist argument that the retina needs extra blood supply, that still doesn’t explain why there has to be a hole in it for those vessels to pass through. (It also doesn’t explain why octopuses do just fine with a non-inverted retina and no blind spot – unless the designer liked them better than us.)
Moving on from this point, Meyer tries to ward off the dysteleology argument by claiming that all design has “inevitable tradeoffs and compromises”. This is true, but misses the point. We’re not faulting adaptations for being less than theoretically perfect, but for being demonstrably suboptimal, such that they could have been unequivocally improved by an intelligent designer without making any tradeoffs. The inverted retina is one. Another, possibly even better example is the human appendix, which in the absence of modern surgery results in about 1 in 15 people dying slowly in great pain from peritonitis. If this is the result of design, one shudders to consider the intelligence of the designer.
We move on to another classic evolutionary exaptation:
“For instance, Gould claimed the panda’s thumb looks jerry-rigged and not designed. Well, experts on the panda say it’s a pretty efficient way of scraping the bark off bamboo.” [p.88]
Again, Meyer has obscured the argument here. It doesn’t matter how efficient the panda’s thumb is: the point that matters is what the panda’s thumb is.
Like most vertebrates, human beings have five digits – in our case, four non-opposable fingers and one opposable finger, the thumb. Pandas have the same five digits, but they are all non-opposable. The panda’s “thumb” is a sixth digit, a pseudo-finger created by enlarging and extending a wrist bone called the radial sesamoid.
The panda’s thumb is not an example of dysteleology in the sense that the inverted retina is. It’s an example of evolutionary tinkering – the haphazard, jury-rigged kind of adaptation that we see again and again in the natural world, what led Richard Dawkins to call evolution a “blind watchmaker”. Because of the random nature of mutation, it’s to be expected that evolution would sometimes solve the same problem in different ways. On the other hand, if there is an intelligent designer, why didn’t he just give the panda four fingers and an opposable thumb, the way primates have?
The jury-rigged, ad hoc nature of adaptation is just what we would expect from evolution. ID, on the other hand has no explanation for this, other than postulating a capricious, whimsical designer who repeatedly reinvents the wheel rather than reusing his own solutions from other lineages. In other words, ID advocates have to assume a designer whose work looks like the product of evolution.
To close out the chapter, Meyer resorts to another all-purpose excuse to explain any examples of dysteleology he might have missed:
“The Bible says there has been decay or deterioration because evil entered the world and disrupted the original design… Based on the biblical account, we would expect to see both evidence of design in nature as well as evidence of deterioration or decay – which we do.” [p.88]
In other words: everything good can be credited to God, everything bad can be blamed on sin (although it’s not explained why human sin resulted in “deterioration or decay” among other species – this is something that Christian apologists since Milton have had difficulty with). One wonders if the appendix represents “deterioration or decay”, and if so, from what. Did pre-Fall humans have an herbivore’s cecum filled with cellulose-digesting bacteria? Did Adam and Eve browse on grass in Eden?
On that note, it’s worth pointing out that this statement seemingly places Meyer in the camp of the young-earth creationists, those who believe in a literal Garden of Eden, a literal serpent tempter and a human race descended from just two people. If that’s the kind of outright nonsense that Strobel is endorsing, his claim to be presenting the latest cutting-edge science goes up in smoke. We’ll get more into this topic in the next chapter.
Other posts in this series: