Specify what is so badly designed bearing in mind that everything has to be maintained, and the more complex something is the more maintenance it requires?
Our bodies are designed so that most of the time they regenerate and heal themselves. Sure medical experts are sometimes involved, but most of the time they do things to help the body help itself.
The body helps itself? The whole medical industry is there simply because the body almost all of the time
cannot help itself. Ever have something as simple as toothache? Popped a couple of pain killers, booked an appointment with the dentist and have the dodgy tooth removed painlessly? Maybe you've seen the film Castaway. Hanks' character has pain so bad he literally knocks the tooth out of his head with a rock. That's what would happen for almost all of human history. Someone held you down and they dug it out with a knife or they smashed it out. Or else you let it get worse and it would eventually kill you.
And that's just your teeth.
I was going to write this myself, but others have done a better job than I could.
From here:
Why the human body has so many design flaws
The spine
The human spine tells this story best.
Our vertebral column has
evolved little from our four-legged, quadrupedal tree-dwelling ancestors, where it functioned primarily as a flexible beam for smooth movement from branch to branch, while also protecting the spinal cord.
When humans adopted an upright bipedal gait, the spine retained these functions. But it was also repurposed for the additional need of supporting our body weight vertically and maintaining our center of gravity, while still allowing the flexibility for us to move. These opposing demands
creates strain.
The characteristic curves of the human spine helps distribute weight, but it also predisposes us to lower back pain, herniated discs and degenerative changes affecting its most important function – protection the spinal cord and surrounding nerves. These conditions are
extraordinarily common, not because the spine is inherently poorly made, but because it’s doing a job it was never originally designed to do.
The neck
Another clear argument against divine design is the
recurrent laryngeal nerve, which takes a course that simply makes no sense to invent.
This nerve, which is a branch of the vagus nerve, predominantly controls our organs’ “rest and digest” functions (such as slowing heart rate and breath). The laryngeal nerve also connects the brain and larynx, helping control speech and swallowing.
Logically, one might expect it to use the most direct route to connect brain and larynx. Instead, it descends from the brain into the chest, loops around a major artery, then travels back up to the voice box.
This detour is not a clever design, but a
historical leftover from our fish-like ancestors when the nerve took a straightforward path around the gill arches. As necks lengthened over evolutionary time, the nerve was stretched rather than rerouted.
This inefficiency can increase our
vulnerability to injury during surgery.
The eyes
Even the eyes
reflect evolutionary compromise.
In humans and other vertebrates, the retina (the light-sensitive layer at the back of the eyeball) is wired “backwards.” This means light must pass through layers of nerve fibres before reaching the photoreceptors – specialised cells responsible for detecting light and converting that into a nerve impulse to send to the brain.
The optic nerve then exits through the back of the retina,
creating a blind spot just below the horizontal level of the eye where no vision is possible. The brain fills in this gap seamlessly, so we rarely notice it.
So while we’ve developed incredible vision and light receptor cells, this has happened at the expense of having a gap in our visual field.
The teeth
Our teeth offer another reminder that evolution prioritises adequacy over durability.
Humans develop two sets of teeth: baby teeth and adult teeth – and that’s all. Once adult teeth are lost, they’re not replaced – unlike sharks, which
continually regenerate teeth throughout life.
In mammals,
tooth development is tightly regulated and linked to complex jaw growth and feeding strategies. This system worked well for our ancestors, but for modern humans it leaves us vulnerable to decay and tooth loss.
Wisdom teeth provide another example of evolutionary lag. Our ancestors had larger jaws, suited to tougher diets that required heavy chewing.
Over time, human diets softened and jaw size decreased. However, the number of teeth did not change as quickly. Many people no longer have space for their third molars – leading to impaction, crowding and often requiring surgical removal.
Wisdom teeth aren’t useless in principle, but they no longer fit comfortably within modern skulls.
The pelvis
Childbirth presents one of the most profound evolutionary compromises. Like the spine, the human pelvis must balance
two competing demands: efficient bipedal walking and birthing large-brained infants.
A narrow pelvis improves locomotion, but restricts the birth canal’s size. Meanwhile, human babies have unusually large heads
relative to body size, resulting in a difficult and sometimes dangerous birth process – often requiring outside assistance.
This tension between mobility and brain size has shaped not only anatomy but also
social behaviour, encouraging cooperative care and cultural adaptations around childbirth.
Evolutionary persistence
Evolution doesn’t necessarily eliminate structures unless they impose a strong disadvantage. So some anatomical features persist despite offering limited benefit.
The appendix, once considered a completely useless evolutionary left-over, is now thought to have
minor immune functions. Yet it can become inflamed, causing appendicitis – a potentially life-threatening condition.
Similarly, the sinuses, have unclear functions. They may lighten the skull or influence voice resonance, and we can even use their size and variability for
forensic identification. But the
sinus’s drainage pathways go direct into the nose, making it prone to regular blockage and infection, a developmental byproduct rather than a purposeful adaptation.
Even tiny muscles around the ears hint at our evolutionary past. In many mammals, tiny ear muscles allow the outer ear (pinna) to swivel, improving directional hearing.
Humans have these muscles, but most people cannot use them effectively.
Our bodies are not perfectly designed, but are a living archive of evolution. Anatomy reveals a historical record of adaptation, compromise and contingency. Evolution does not aim for perfection; it works with what is available, modifying structures step by step.