“Bad Designs” in Nature: Evidence for Evolution (Part 4)

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Textbooks may claim that nature includes “bad designs” pointing to evolution rather than a Creator. Let’s see how to think through such arguments with some of the 7 Checks of Critical Thinking.

After months of wondering, I just realized why a certain “bad design feature” exists in my laptop bag. That bag traveled around the planet during my 360 in 180 adventures documenting Christian students’ university experiences. But all the while, I never understood the purpose of the bag’s apparently “badly designed” outer panel.

The panel contains two zippered compartments, perfect for stashing change, documents, and other essentials within easy reach. But why, I wondered, does the panel’s frontmost compartment also include a zipper at the bottom? If the zipper happened to open, everything inside could fall out!

Questioning why the bag’s designers had engineered such an insecure feature, I stashed my valuables in the compartment without the bottom zipper. Unfortunately, the main zippers on both compartments broke during my trip, leaving me without a truly reliable outer compartment. Talk about bad design!

“Bad Designs” in Nature

As a student, I heard that—like my bag includes suboptimal zippers, nature contains “bad designs” which supposedly point to evolution rather than creation. To quote my evolution textbook,

The ‘accidents’ of evolutionary history explain many features that no intelligent engineer would be expected to design. For example, the paths followed by food and air cross in the pharynx of terrestrial vertebrates, including humans, so that we risk choking on food. The human eye has a ‘blind spot’ . . . caused by the functionally nonsensical arrangement of the axons of the retinal cells . . . .” 1

So, are these “bad designs” that suggest evolution?

Let’s think about it, using some of the 7 Checks of Critical Thinking.

1. Check Scripture

Genesis explains God designed everything to be “very good”; however, creation didn’t stay perfect because of sin. Biblically then, we’d expect that so-called “bad designs” are probably not bad at all but exceptionally functional given their relevant constraints. They might be subject to hazards in our sin-cursed world, like choking, but we shouldn’t be surprised to find that God had the foresight to accommodate for such hazards.

2. Check the Challenge

Nonetheless, calling these designs “suboptimal” to make them seem like evolutionary flukes counters clear biblical teachings. So, let’s go onto Check #3.

3. Check the Source

Where is the message that nature contains “bad designs” coming from? It’s coming from a textbook which uses human reasoning as its authority, and humans are not all knowing. This point will be worth keeping in mind for the next critical thinking checks.

4. Check the Definitions

Now we can ask, “Who’s defining what counts as a ‘good’ or ‘bad’ design?” These terms are pretty subjective, open to interpretation. For instance, you might say, “Thumbs are a good design because they’re optimal for grasping.” And I might counter, “Thumbs are a bad design because I think they’d be more useful with a wider range of motion.”

However, I’m not all knowing, like God. I don’t fully understand the hand’s mechanical constraints—how the muscles and joints all need room to work together with other structures to make the whole hand as useful and efficient as possible. So, to call a design “bad,” we basically have to suggest we know more than God would.

5. Check for Propaganda

To identify any non-logical persuasion in “bad design” arguments, we can apply the question, “is this message true or false because . . . ” to ask, “Is it true that a design is bad because we might not fully understand why God would have designed it that way?” No. From a biblical perspective, whether any one person understands why structures like eyes or throats are designed a certain way doesn’t determine whether God is a good designer. This is especially true because God is all knowing and we aren’t.

6. Check the Interpretations

What’s the observational science behind “bad design” claims? In this case, facts we can observe today include the realities that both food and air pass through the throat, which can lead to choking, and that optic nerves create small blind spots. The interpretation from historical science is that these features are products of evolution and are suboptimal designs. What assumptions are behind this interpretation? Besides assuming we know more than an intelligent Designer would, and that evolution can produce intricate living structures like eyes in the first place, we might be forgetting that hazards which may arise from blind spots or choking weren’t normal parts of God’s very good creation.

If we look even deeper into the observational science, we can see there are many very good reasons the eye and pharynx look the way they do, and they do include features to accommodate for hazards of our fallen world. For instance, there’s a flap in the pharynx called the epiglottis which seals off the windpipe when we eat, so we don’t normally choke. Likewise, the eyes are paired to accommodate each other’s functionally necessary (but very minimal) blind spots.

Back to the Laptop Bag

Like the pharynx or retina, could my laptop bag’s weird zipper exist for a reason? I hadn’t thought so until today, writing this blog post from a plane. My laptop bag felt especially heavy against my shoulder as we cued to board, but I noticed a fellow passenger wasn’t experiencing the same problem. His bag included a built-in sleeve through which he could thread the handle of his suitcase, allowing the suitcase (rather than his shoulder) to carry the load.

I should find myself a bag like that, I decided.

On the plane, I opened my “badly designed” bag and whipped out my laptop to write about “bad designs” in nature. While contemplating how to begin, I remembered the bag’s bottom zipper. Of course! Why hadn’t I seen it before? That zipper converts a useful compartment into an equally useful sleeve for securing the bag to a suitcase. Sure, the zipper might work its way open in unlikely circumstances, but—like each eye accommodating for the other’s blind spot—the other compartment remains a secure storage alternative. The fact the main zippers broke doesn’t change that the bag was originally well designed any more than hazards of our fallen world imply God didn’t create features like the pharynx “very good.” Moreover, my bag’s functional specificity—perfectly engineered to fit a human shoulder (or a suitcase handle)—reflects its intelligent design.

Ultimately, whether contemplating lifeless bags or living bodies, a little biblical, critical thinking about “bad designs” often reveals that those designs exist for a reason. Despite our fallen world, “badly designed features” are not so bad at all, but rather, point to their masterful Designer.


  1. Futuyama, "Patterns of Evolution," In Evolution, 3rd ed. (Sunderland, MA: Sinauer Associates, 2013), 54.


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