Design flaws in organisms indicate evolution, not intelligent design

[Compassionist]

The existence of design flaws in living organisms is often cited as evidence for evolution by natural selection rather than intelligent design by an all-loving, all-knowing, and all-powerful deity. If such a being existed and created life intentionally, we might expect optimal design yet what we see instead are structures and processes that are inefficient, prone to failure, or even harmful.
Here are some significant biological design flaws that point to evolution rather than perfect design:
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1. Human Birth Canal vs. Big Brain
Flaw: Human babies have large heads due to our large brains, but the human pelvis is narrow for bipedal walking.
Result: Childbirth is extremely painful and dangerous a leading cause of death historically.
Evolutionary Explanation: Our ancestors evolved larger brains and upright walking separately, leading to a dangerous compromise.
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2. Wisdom Teeth
Flaw: Most people don't have room for third molars, causing impaction, infections, and pain.
Result: Many need surgery to remove them.
Evolutionary Explanation: Our ancestors had larger jaws due to diet, but modern humans' jaws shrank faster than tooth evolution could keep up.
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3. Human Retina Is Backward
Flaw: The photoreceptor cells in the human eye are behind layers of neurons and blood vessels.
Result: Creates a blind spot and reduces image quality.
Evolutionary Explanation: The eye evolved incrementally, not from a clean-slate design.
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4. Recurrent Laryngeal Nerve (Giraffe Example)
Flaw: This nerve travels from the brain to the larynx, but loops around the aorta.
Result: In giraffes, it travels over 15 feet instead of a direct path of a few inches.
Evolutionary Explanation: It's a leftover from fish ancestors, where this path made sense. Evolution modified existing structures rather than redesigning from scratch.
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5. Human Menstrual Cycle
Flaw: Humans shed the uterine lining even if not pregnant, wasting resources and causing pain.
Result: Menstrual cramps, anemia, mood changes.
Evolutionary Explanation: Other mammals reabsorb the lining. Our approach may have evolved due to pathogen risks in internal fertilization.
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6. Shared Path for Food and Air
Flaw: The esophagus (food) and trachea (air) share an entrance.
Result: Risk of choking a leading accidental cause of death.
Evolutionary Explanation: The throat evolved in stages, without foresight.
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7. Human Spine and Back Pain
Flaw: Our spine is an S-curve not ideally suited for upright walking.
Result: Many people suffer chronic back pain, herniated discs, etc.
Evolutionary Explanation: Our ancestors were quadrupeds. The upright posture evolved later, leading to inefficient structure.
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8. Brain Vulnerability and Mental Illness
Flaw: The brain is highly energy-consuming and prone to many dysfunctions.
Result: High rates of depression, anxiety, bipolar disorder, schizophrenia, etc.
Evolutionary Explanation: Natural selection favored reproductive success, not mental wellness or long-term wellbeing.
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9. Knee Joint Design
Flaw: Knees bear immense strain, especially the ACL (anterior cruciate ligament), which often tears.
Result: Common injuries in sports and aging.
Evolutionary Explanation: Knees evolved from quadruped ancestors, not optimally engineered for bipedal running and jumping.
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10. Genetic "Junk" and Mutations
Flaw: The genome is full of non-coding or redundant DNA and is prone to harmful mutations.
Result: Genetic diseases, cancer, and congenital defects.
Evolutionary Explanation: DNA accumulates "baggage" over time. There's no intelligent editing or streamlining process.
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11. Susceptibility to Cancer
Flaw: Cells divide for life but are prone to mutations that cause cancer.
Result: One of the top global causes of death.
Evolutionary Explanation: Cell division is essential for life, but natural selection can't eliminate all cancer risk especially after reproductive age.
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12. Human Psychology Biases
Flaw: We are prone to cognitive biases (e.g., confirmation bias, tribalism, overconfidence).
Result: Misjudgments, discrimination, and conflict.
Evolutionary Explanation: These evolved to enhance survival in specific environments, not to produce truth-seeking rationality.
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If we were designed by an omnibenevolent, omniscient, and omnipotent being, such flaws are impossible to justify. Evolution by natural selection, on the other hand, explains these quirks and imperfections as the result of a messy, blind, trial-and-error process where old parts are tweaked, not replaced, and survival/reproduction, not perfection, is the end goal.

[Jose Fly]

I was taught in science class that it starts out as a hypothesis, then develops into a theory, and finally into a fact, when proven, @Jose Fly. Was my teacher wrong?

Yes, very much so. Scientific theories explain facts, they don't become facts. Every scientific theory has a fact that it explains. For example...

The Germ Theory of Disease explains how germs cause disease, which is a fact.

The Atomic Theory of Matter explains how matter is made up of atoms, which is a fact.

The Theory of Evolution explains how populations evolve, which is a fact.

How would you classify evolution among these categories, if they are valid?

Evolution is simply a fact, since we see it occurring all the time, pretty much every day.

Just because it is accepted in the scientific community doesn't mean that every single scientist accepts it, does it? I know some scientists who are Christians who believe in microevolution, not macroevolution?

There are scientists who disagree with a spherical earth and/or that the earth orbits the sun. In fact, I can't think of anything that absolutely every single scientist on earth agrees to.

Do you believe in both? If so, why?

I no more "believe in" evolution than I "believe in" erosion. They're both simply observed reality.

[BruceLeiter]

[Replying to Jose Fly in post #361]

What about microevolution versus macroevolution, @Jose Fly? People don't observe the changes of one species into another one, which I understand to be macroevolution and which then remains a theory, doesn't it?

[Jose Fly]

People don't observe the changes of one species into another one, which I understand to be macroevolution and which then remains a theory, doesn't it?

The evolution of new species has been observed many times, both in the wild and in lab experiments.

https://evolution.berkeley.edu/evo-news ... real-time/

https://biologyeye.com/speciation-examples

[BruceLeiter]

[Replying to Jose Fly in post #363]

But @Jose Fly, how have you or anyone else "seen" the ape-like creature change into a human? Doesn't that fact that no one has observed it happening make it only a theory, not a fact?

It depends on the starting point of whether you start with the assumptions of the Bible or the givens of science to end up with your "facts," doesn't it?

In other words, the Bible is clear that Adam and Eve are special creations of God (Genesis 2), not related to any animal, though similar to them in some ways. That's where I start.

Regarding the Grand Canyon, I believe that God has used natural processes to create that magnificent chasm, perhaps over millions of years (the first six "days"), and then reveals his amazing handiwork with the receding flood.

[Jose Fly]

But @Jose Fly, how have you or anyone else "seen" the ape-like creature change into a human? Doesn't that fact that no one has observed it happening make it only a theory, not a fact?

No. To repeat...

Scientific theories explain facts, they don't become facts. Every scientific theory has a fact that it explains. For example...

The Germ Theory of Disease explains how germs cause disease, which is a fact.

The Atomic Theory of Matter explains how matter is made up of atoms, which is a fact.

The Theory of Evolution explains how populations evolve, which is a fact.

It depends on the starting point of whether you start with the assumptions of the Bible or the givens of science to end up with your "facts," doesn't it?

No, facts are facts regardless of where you "start". That populations evolve is a fact simply because we see it happen all the time.

In other words, the Bible is clear that Adam and Eve are special creations of God (Genesis 2), not related to any animal, though similar to them in some ways. That's where I start.

Then the conclusions of science don't really matter to you, do they?

Regarding the Grand Canyon, I believe that God has used natural processes to create that magnificent chasm, perhaps over millions of years (the first six "days"), and then reveals his amazing handiwork with the receding flood.

Understood.

[BruceLeiter]

[Replying to Jose Fly in post #365]

I think I asked you before, @Jose Fly, about the distinction between microevolution and macroevolution. Many Christians believe that God has used microevolution to diversify animals and humans, for example into races, but don't believe that whole species change into another species, because the Bible clearly says that humans are his special creation. Do you distinguish between those two changes? If so, why? If not, why not?

[Jose Fly]

I think I asked you before, @Jose Fly, about the distinction between microevolution and macroevolution. Many Christians believe that God has used microevolution to diversify animals and humans, for example into races, but don't believe that whole species change into another species, because the Bible clearly says that humans are his special creation. Do you distinguish between those two changes? If so, why? If not, why not?

First, microevolution and macroevolution are the same process (evolution), with the difference between the two being the period of time over which the process occurs. It's very much like erosion. If we watch a glacier erode material in a valley over the course of a year, we'll see relatively small amounts of material being eroded. But the same process occurring over much longer periods of time will erode a lot more material and lead to much more large-scale changes to the valley.

The same mechanisms that are behind microevolution (e.g., mutation, selection, drift) are also behind macroevolution. The only difference is time.

Second, as I demonstrated in an earlier post, the evolution of new species is something we've seen happen many times. So denying that it occurs is denying observed reality.

Finally, if for religious reasons some people don't accept the conclusions of scientists about the evolutionary history of life on earth, that's certainly their choice. Throughout history various religious groups have refused to accept all sorts of things that they see as conflicting with their beliefs, so that some Christians refuse to accept human-primate common ancestry because of how they read the Bible isn't unprecedented or even surprising. People are generally free to believe or not believe whatever they want.

[BruceLeiter]

[Replying to Jose Fly in post #367]

As are you free, @Jose Fly.

[Jose Fly]

[Replying to Jose Fly in post #367]

As are you free, @Jose Fly.

Indeed.

Sometimes I think folks can mistakenly assign too much significance to these debates and the fact that some people don't believe the same things they do. Some people don't accept something as basic as that the earth is spherical and orbits the sun for example. Does that really matter to me? Does it affect me in any way? Nope.

Similarly, if some people don't accept that humans share a common ancestry with other primates, unless they're engaging in a campaign to change school curricula or something, it doesn't really matter to me. They can believe or don't believe whatever they like and we'll just go our separate ways.

[The Barbarian]

[Replying to Jose Fly in post #365]

I think I asked you before, @Jose Fly, about the distinction between microevolution and macroevolution. Many Christians believe that God has used microevolution to diversify animals and humans, for example into races, but don't believe that whole species change into another species, because the Bible clearly says that humans are his special creation. Do you distinguish between those two changes? If so, why? If not, why not?

Evolutionary theory has shown that there are no biological human races. Once there were, but not now. In fact, most creationist groups now admit the evolution of new species and genera. Sometimes a bit more than that. Speciation is an observed fact. That's what macroevolution is. I suspect you've confused macroevolution (an observed fact), with universal common descent, an inference from genetic analyses.