Inept Design

A fourth objection to the ID movement is theological. It alleges that God, if He were the designer, would have done better. Although our planet is teeming with life, most of the universe is hostile to all known forms of biological life, which doesn’t flourish in the cold near-vacuum of outer space. If God finely tuned the universe for life, then why is so much of it barren and sterile, and why did it take billions of years before the first life appeared? Moreover, if God designed living creatures, then why do some biological structures and systems appear to be poorly designed, exhibiting flaws that a supremely intelligent engineer presumably would have avoided?

As an example of the latter phenomenon, critics of ID have cited a puzzling feature of the human eye. The eye is enormously complex and boasts sophisticated capabilities that surpass man-made imaging technologies in many ways, but it has one peculiar feature which, from an engineering standpoint, looks like a terrible mistake: the nerves are wired backwards. Rather than connecting to the light-sensitive retina from behind, the optic nerves connect to the front of the retina, obstructing some of the light that reaches it.

diagram of the retina
The Human Retina

Light-sensitive rod cells and color-detecting cone cells are situated at the back of the retina, with neurons (nerve cells) in front of them. The nerve fibers pass through a small hole in the retina on their way to the brain.

Credit: Christine Blume, Corrado Garbazza, and Manuel Spitschan, Creative Commons (CC BY 4.0)Image source: Wikimedia Commons. The labels have been modified from the original.

Worse still, these nerves must pass through a hole in the retina on their way to the brain, leaving a small blind spot where the hole is located. (We don’t notice this blind spot because our brains subconsciously interpolate, filling in the gap with information from the other eye or from the surrounding region. However, you can experience the effects of this blind spot by following the directions in the figure below.) Other vertebrate animals share this apparent defect; but cephalopods like the octopus have their optic nerves wired in the intuitively correct way, connecting to the back of the retina, so there is no obstruction and no blind spot. If eyes are a product of intelligent design, the objection goes, then why did the designer get it right for octopuses yet bungle it for the rest of us?

blind spot test
Blind Spot Test

Close your left eye and look at the letter R with your right eye. Move your face closer or farther from the screen until your open eye is about three times farther away than the distance between the two letters. The letter L will disappear when it is in your right eye’s blind spot. Similarly, close your right eye and look with your left at the letter L to make the R disappear.

I’ll refer to criticisms like these as inept design objections. Inept design objections are, in my opinion, the most interesting challenges to ID. Although the ID movement doesn’t specify the identity of nature’s designer, God is surely the most plausible candidate. So, if the objection succeeds in ruling out God as designer, this would seem to constitute strong evidence against the thesis that nature was designed at all. The challenge is especially pressing from a Christian perspective, since we believe God created the universe and its inhabitants.

Before addressing inept design objections, I’d like to make a preliminary observation about them. The objections tacitly acknowledge that design hypotheses yield predictions about what we should expect to see in nature. If God or any other superintelligent being is the designer, we should expect to find ingeniously-designed systems rather than clumsily-designed ones. Thus, these objections are inconsistent with the aforementioned objection by Elliott Sober and others who claim that ID makes no predictions and is therefore untestable. Sober recognizes the logical inconsistency between the two critiques:

Biologists often present two criticisms of creationism [and ID]. First, they argue that the design hypothesis is untestable. Second, they contend that there is plenty of evidence that the hypothesis is false. Obviously, these two lines of argument are in conflict.Elliott Sober, “The Design Argument,” in Neil A. Manson (ed.), God and Design: The Teleological Argument and Modern Science. (New York: Routledge, 2003), 42.

This presents a dilemma for critics of ID. They may criticize ID for being untestable, or they may argue that it has been shown false, but they can’t have it both ways. Sober, for his part, opts for the first horn of the dilemma: he argues that ID is untestable. As we saw on the previous page, however, his argument doesn’t hold up to scrutiny. So, what about the other horn of the dilemma? Has ID been falsified?

To address allegations of inept design, let’s begin with the charge that the universe as a whole is poorly designed. If God fine-tuned the universe to make life possible, then why is so much of the universe lifeless? Does the vastness of space and time, compared to the size of Earth’s biosphere and the miniscule span of human history, show that God did not design the universe with us in mind? Christian astrophysicist Hugh Ross masterfully handles these questions in his book Why the Universe is the Way it Is. He identifies in scripture eleven distinct purposes God fulfilled by creating the universe this way. God made the universe this way in order to demonstrate His divine nature, to show us our own human nature, to facilitate the conquest of evil, and to prepare and train us for our future role in His eternal kingdom, among other significant spiritual, moral, practical, and aesthetic purposes. After elucidating numerous ways in which the vastness of space and time (in comparison to the brevity and insularity of human existence) serves all of these purposes and more, Ross concludes:

It’s astounding that a single universe could simultaneously accomplish such a complexity of intertwined yet distinct purposes. Skeptics who claim God could have made a better home for humanity might ponder what it would take to design a home that simultaneously accomplishes all this one does.Hugh Ross, Why the Universe is the Way it Is (Grand Rapids: Baker Books, 2008), 163.

On the other hand, we shouldn’t expect to understand all of God’s decisions. “If we are humble,” Ross admits, “we may recognize that the Creator may have other purposes for the universe that he has not yet chosen to reveal to us. We can expect at least some mysteries to remain regarding why the universe is the way it is.”Hugh Ross, Why the Universe is the Way it Is (Grand Rapids: Baker Books, 2008), 163.

This last point is equally applicable to questions of design in biology. Some of God’s design decisions may be inscrutable from our limited human perspective. Given that God’s ways and His thoughts are immeasurably higher than ours (Isaiah 55:9), we should anticipate limitations in our own abilities to understand why God made things the way He did. Why is the vertebrate eye wired backwards? God might have reasons that have not been revealed to us, or reasons we couldn’t even comprehend.

Then again, perhaps we can discover the reasons after all. Many examples of seemingly inefficient or clumsy design have turned out, upon closer inspection, to exhibit ingenious contrivances that transform apparent flaws into clever features. (As software engineers like to say, “It’s not a bug, it’s a feature!”) The eye is a case in point. Recent discoveries have revealed that human and other vertebrate eyes contain specialized cells called Müller cells, which act as living fiber-optic cables. Müller cells are stunning examples of clever engineering. Spanning from the front to the back of the retina, they provide structural support for delicate neurons while also carrying incoming light directly to the rod and cone cells where the light is detected.Kristian Franze et al, “Müller Cells Are Living Optical Fibers in the Vertebrate Retina,” Proceedings of the National Academy of Sciences 104 (May 15, 2007): 8287-8292. Amazingly, the Müller cells do not merely allow the light to bypass obstructions; they also preferentially guide specific wavelengths (colors) of light to cones optimized for those wavelengths, thereby improving color vision, while passing off other wavelengths to adjacent rods to boost visual acuity in dim lighting conditions.Amichai M. Labin et al, “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” Nature Communications 5, (2014): 4319. For further discussion, see Chapter 2 of Michael Behe’s book Darwin Devolves: The New Science about DNA that Challenges Evolution (New York: HarperCollins, 2019), especially pp. 48-50. Because of this ingenious arrangement, the convoluted wiring of vertebrate eyes provides visual advantages over the straightforward wiring found in cephalopod eyes. Thus, as one science journalist observed when reporting the discovery in 2014, “having the photoreceptors at the back of the retina is not a design constraint, it is a design feature.”John Hewitt, “Fiber optic light pipes in the retina do much more than simple image transfer,” (July 21, 2014)

The seemingly backwards orientation of the vertebrate retina affords other benefits as well, such as making the eye more compact and enabling more efficient image preprocessing.Tom Baden and Dan-Eric Nilsson, “Is our retina really upside down?”, Current Biology 32 (April 11, 2022). In a recent article, biologists Tom Baden and Dan-Eric Nilsson compare the inverted retina with the forward-facing retina of cephalopod eyes, noting that neither type of eye is poorly constructed. Each has its own distinctive advantages, so “it is not possible to say that either retinal orientation is superior to the other.”Tom Baden and Dan-Eric Nilsson, “Is our retina really upside down?”, Current Biology 32 (April 11, 2022). After examining the pros and cons of each design, they summarize: “Both the inverted and the everted [forward-facing] principles of retinal design have their advantages and their challenges, or shall we say ‘opportunities.’ The good points with the vertebrate way of making an eye is that it provides ample space close to the photoreceptors for early visual processing, and in very small animals, the visual system can be made extremely compact. Good points with the cephalopod everted retina are that there is no blind spot in the visual field, and the space in front of the photoreceptors is free of optically compromising neural tissue.” Although Baden and Nilsson credit “the efficiency and ingenuity of evolution” rather than an intelligent designer for the well-engineered structures of both types of eyes, they argue that the counterintuitive structure of vertebrate eyes should not be considered a defect. To the contrary, “vertebrates include birds of prey with the most acute vision of any animal, and even in general, vertebrate visual acuity is typically limited by the physics of light, and not by retinal imperfections.” Far from exhibiting careless engineering, the design could hardly be improved. “In terms of performance,” the two biologists marvel, “vertebrate eyes come close to perfect.”Tom Baden and Dan-Eric Nilsson, “Is our retina really upside down?”, Current Biology 32 (April 11, 2022).

Many similar examples could be cited.For further discussion of the previous case and a couple of additional examples, see the article “Verdicts of ‘Poor Design’ in Biology Don’t Have a Good Track Record,” by biologist Emily Reeves. Maybe all cases of apparently sloppy design in biology are, like the previous case, really ingenious designs that we have hitherto failed to appreciate. Alternatively, perhaps God has inscrutable reasons for employing sub-optimal designs in some of His creatures. Either way, the appearance of poor design in some biological structures should not diminish our wonder at the overwhelmingly marvelous designs on display throughout the biological world.