God and "Bad Design"
Shear, not Sneer
January, 2022
A popular category of arguments for God's existence is the suggestion of "design." This implies that complexity and specific arrangement, as seen in living things, is evidence of deliberate planning. A primary rebuttals to these "teleological arguments" is a claim that the critic could have done better. This type of response suggests some aspect of biology is inefficient, less-than-optimal, or just plain "wrong." Those examples are held up as proof that biological "design" is not very good, and unlikely to be the product of an omniscient mind.
As a degreed mechanical engineer, I have a unique perspective on those conversations. I frequently hear inexperienced engineers and laymen criticize existing designs, sneering at what they perceive as flaws. But when you ask them to come up with something better, reality sets in. The critic comes to realize the design in question is a choice. Not an oversight, or an error, but a decision made for a reason. Suddenly or eventually, the sneering critic usually figures out that the original designer wasn't stupid. Rather, they were striking a deliberate balance between competing interests.
That's not to say human engineers can't make bad choices or mistakes. They certainly can; we're not omnipotent or omniscient. But in most cases, what the uninformed person sees as a mistake is simply a decision they don't understand. Where critics—both of mechanisms and Intelligent Design—fail is typically by assuming any design choice they don't immediately understand must be a mistake.
An especially common category of these complaints is over weak points in a system: pieces or parts that fail more often than others. For example, a farm tractor might attach the main transmission to a powered tool using a small metal pin. Similar examples are seen in things like pumps, augurs, snow-throwers, and other equipment. These pins are notably weaker than the rest of the machine; they're prone to breakage. Each breakage means the tractor stops working, and the pin must be replaced. I've seen aggressive users break the same pin multiple times in a single working shift.
Isn't that bad design? The solution seems obvious: connect the equipment using a thicker, stronger pin! Or just make the connection permanent, and much stronger. For the non-engineer, it can be maddening to imagine such a silly design choice. But those connecting links have a name: "shear pins." When the tool is stressed beyond a certain point, only that link fails. Stress that might otherwise damage the transmission, a gear, or some other part instead breaks a cheap, easily replaced part. Without that weak point, overloading a machine would require extensive repairs. Making the transmission so sturdy that it's impossible to break may also mean making it a hundred times as expensive. Shear pins are examples of a design which sincere-but-ignorant people think of as a "flaw," when it's crucial for keeping the system running.
That same concept applies to more obscure design choices. Experienced material handlers know exactly what shear pins are for. But they might not be as informed about complex engine parts. They may not realize manufacturing is part of machine design. Parts need to be efficient and cost-effective to make. Also relevant is intended use: a machine meant to move 1,000 pounds is designed for that task, not something three times as large. There may be legal regulations, safety concerns, or other behind-the-scenes rules being applied.
All those concepts apply to God's design of biological systems, as well. By and large, most biological "weaknesses" or design flaws eventually dissolve once studied without prejudice. The "vestigial" human tailbone has been proven to serve important functions. The tailbone connects to ligaments that greatly influence human posture, even when we're seated. Similarly, the appendix at the intersection of the large and small intestines helps store materials that balance gut bacteria. Its placement makes it possible for the digestive system to quickly reset after ailments like diarrhea. Efficiency is also an important part of biology. It's the reasoning behind features common to males and females, as well as the similarity of DNA in different species.
A favorite target of anti-design critics is the human eye. Humans have a "blind spot" because light sensors are on a surface interrupted by the connecting point of the optic nerve. The sensors themselves are also backwards from those of other types of animals: light passes through tissues before it enters the seemingly-backwards receptors. But the existing design allows for greater filtering, processing, and sensitivity. Inverting these sensors, or placing them in the front of the eyes, would make our eyesight less-well-suited to our needs. Those "flaws" are design choices which give benefits.
Notable pop-culture atheists have criticized the eye as an example of poor design. As someone with an engineering background, their sneering comes across like a suburban homeowner raging at the shear pin in his snow-thrower. He's cursing out the engineer for costing him a few dollars and a few minutes of repair…not understanding how that design element prevented him from wrecking the entire machine when he overloaded it.
An uninformed critic rarely needs more than a quick explanation to realize a mechanical design "mistake" is almost always a reasoned choice. One doesn't need a degree in engineering to grasp the purpose of a shear pin. In the same way, advanced study of biology isn't always needed to see why God made some design choice in nature. In other cases, it takes greater understanding to realize the reasons behind those arrangements. In both circumstances, careful examination usually proves that sneering is not the wisest way to approach design elements one does not immediately understand. As this month's spotlight verse points out, God's works are truly wonderful.
-- Editor
