Quirks of Human Anatomy
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When I was a kid, I got my tonsils removed "because they were useless and a source of illness".
I've recently heard that tonsil removal is now more disputed: it may collect filth, sure, but it may also prevent it from going deeper into the body, which may cause more serious illnesses.
Given its vast complexity, and the timeline of its creation/evolution, I remain skeptical over bold claims about the human body. It's really missing an "as far as we know." The ability to go beyond what is known is paramount to the progress of science, and historically attested with some intensity (e.g. Earth's shape, relativity with time/space & axiomatic geometry). Humility thus feels like a better posture.
Who would let a junior dev trim bits, or boldly modify a decades old codebase?
For males not to have nipples, they'd need to be actively destroyed, which poses a risk for females to also not have nipples, which is much worse than males having harmless, inactive nipples.
The amount of testosterone in women is not zero, likewise the amount of estrogen in men is not zero as well, and breast tissue does serve some purpose in regulating hormoe production, even in men.
Mammalian fetuses all start out the same and sexual dimorphism happens several weeks into development. The same structure that eventually develops into a uterus can instead develop into a penis/prostate. Testicles and ovaries are the same tissue early in development, just like the glans and clitoris.
Biology doesn't generally suppress one entire set of organs in favor of another. They're built from the same precursor tissue and only diverge after sex hormones are activated. Biology and evolution modify existing structures, it does not typically erase one structure and replace it with another.
In addition, intersex humans exist. There are documented incidences of males born with uteri, external genitals can form halfway between male and female. Biology can get very messy sometimes. Sex is not a hard binary switch, it's a sliding scale just like most biological features. Only most individuals are at one end or the other, there's a lot of room between.
I will just say, the human body in particular has only been around for a vanishingly short period of time in evolutionary terms. A lot of the quirks and arguable flaws identified in this piece (painful childbirth through the pelvis, back pain) and others (varicoceles in the left internal spermatic vein, hernias, other pelvic floor disorders) can be attributed to our very recent move to full bipedalism.
If we’re talking about features we share with other mammals or even other primates, sure, they’ve probably stood the test of time for a reason. But for features that have only really been in existence for a couple million years, those I don’t think we should treat with the same kind of reverence.
"as far as we know." Every few years, I see in the headlines stuff like "oldest 'human' ever found in X." The theory of evolution itself has morphed since Darwin [0], and is probably far from being in its definitive form.
The timeline remains astronomical w.r.t. a human life, and the perception of a single human. A few centuries ago, we may have burnt people for proposing something like the theory of evolution.
> [...] can be attributed to our very recent move to full bipedalism
Admittedly. But it's still not contradictory with this still having unknown roles. Actually, multi-causality feels like a good way to ensure the stability and solidity of a design: "don't put all your eggs in the same baskets", portfolio diversification, etc.
Thinking about painful pregnancies and birth, [1] hints at the "need" for pain/discomfort. If it's indeed some sort of a necessity, then it may be more of a feature than a bug for us to experience pain directly, through the womb, etc.
[0]: https://en.wikipedia.org/wiki/History_of_evolutionary_though...
The discovery of older humans does not respond to the point you’re arguing against — in evolutionary time scales, humans are recent.
> The theory of evolution itself has morphed since Darwin [0], and is probably far from being in its definitive form.
Fields continue to change as they grow older, but the magnitude of changes tend to get smaller. Of course evolution will change, but it would be very surprising to have large changes in the fundamental elements
> Thinking about painful pregnancies and birth, [1] hints at the "need" for pain/discomfort.
Evolution only optimizes for what results in dna being passed on. It doesn’t care about ancillary details. I think painful childbirth pretty much shouldn’t matter much to evolution, because the parents have no control over the birth at that point — it’s happening one way or another. Perhaps it promotes bonding with the child, or something like that? But in general, I think it’s wrong to say “evolution provided X, so X must be needed”. If X has no significant effect on the passage of dna, then it could just be random noise.
I meant, evolutionary time scales themselves are subjected to accuracy issues. The measurements techniques themselves are subject to accuracy issues as well.
> but the magnitude of changes tend to get smaller
Agreeing with the tendency, but there are great exceptions; physics comes to mind. The fact that we still don't properly understand QM, and physics being conceptually at the root of many sciences, a proper understanding of it may force to revisit a few things "up there".
> I think painful childbirth pretty much shouldn’t matter much to evolution, because the parents have no control over the birth at that point
Sorry, I (genuinely) don't get the argument.
Regardless, I saw articles [0][1] linking (minor) DNA alterations to exercising. It'd be interesting to see how body stresses in general could impact DNA, and how this would wrap up with evolution.
> then it could just be random noise.
Well, the problem with "noise", is that from the outset, we can't know distinguish between "actual noise" − assuming such a thing exist − or if it's merely a reflection of ignorance. The latter at least gives us direction in which to search stuff. So "evolution provided X, so X _may_ be needed" I guess
[0]: https://www.nature.com/articles/s41514-025-00217-0
[1]: https://cordis.europa.eu/article/id/34391-scientists-discove...
Hasn't it been settled for a while that they're part of the immune system? Wiki is clear [0] on the subject; they're there to repel bacteria. They're quite important and removing them, unless there is no other choice, seems like a terrible idea.
A 2022 article [1] quotes an ENT advocating it for kids with frequent (3 to 4) bacterial throat infections in winter.
It's often difficult for new ideas to get through people who have upheld the same point of view for decades though. Especially for "selective" fields like medicine (ego issues are probably more developed than in less selective fields). Let alone in fields strongly impacted by money or politics.
[0]: https://www.idref.fr/234378662
[1]: https://www.santemagazine.fr/sante/maladies/maladies-infanti...
"Chesterton's Fence": you shouldn't tear down a fence (or a piece of code) until you understand exactly why it was put there in the first place.
Nothing in the human body was placed with intent. It’s still important to understand what it does before you go messing with it, but it’s a very different sort of thing.
"In the matter of reforming things, as distinct from deforming them, there is one plain and simple principle; a principle which will probably be called a paradox. There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, "I don't see the use of this; let us clear it away." To which the more intelligent type of reformer will do well to answer: "If you don't see the use of it, I certainly won't let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it.""
>Who would let a junior dev trim bits, or boldly modify a decades old codebase?
Ones who does not understand the idea of the "Chesterson's Fence"
I suspect the next round of backpedalling will be around the current wisdom teeth removal fad.
Initially considered a useless vestige, now thought to be involved with maintaining gut bacteria.
Pre-medicine you got appendicitis and just died painfully.
In giraffes that nerve is several meters long.
Another interesting one is the auricular tubercle[1], where the genetic trait of a "pointy" ear found in other mammals reappears in some humans.
E.g. many of these items are simply vestigial in some sense, where their presence doesn't actively harm the species and it doesn't impose any substantial energy budget. E.g. the current top comment here is about male nipples. Male nipples may be "useless", but they're not actively harmful (and they can certainly be pleasurable during sex), so there is no evolutionary pressure to get rid of them. The perineal raphe (i.e. the "male taint stitch") also has no purpose but is simply a byproduct of how the male forms in utero.
As the article points out, most of the other "quirks" are simply what evolution had to deal with. You may say the eye is "weird" because the photoreceptors lie behind the ganglion cells, but it certainly works quite well, generally. And it doesn't "have to" be this way. Octopus eyes are completely the opposite and a great example of convergent evolution.
Other examples are simply tradeoffs. There is pretty obvious survival advantage for humans having a large brain, but this then adds complexity for how the head gets out of the relatively small pelvic canal.
I honestly didn't see any examples in this list that aren't well understood and well explained by scientists. If anything most of these provide excellent examples of how evolution works.
An unfortunate habit of medical messaging is to assert that absence of evidence is evidence of absence. If you haven’t studied a phenomenon well enough, you simply assume that it doesn’t exist or is not important.
Some people will say that this is important, because the public needs simplified messages. That viewpoint is misguided and denies patients autonomy by denying them the information needed to weigh matters themselves. It rightly causes many to view the advice they receive with suspicion toward an untrustworthy salesman who is either ignorant or intentionally misleading.
These flaws were left in so there would be no proof of a creator. Because with proof, there is no faith. And faith is a requirement of winning.
Imagine how hard it must have been to design “flaws” like these but still allow humans to survive. I can’t. Therefore, you can’t. Only an omnipotent god could do it.
Checkmate atheists!
I'd say kill that advertising for a few generations, then see what is left.
That would almost have me believing in a god.
In the guinea pig, the large head at birth is provided for by the carteliginous symphysis joint in the hips detaching. However unless the animal gives birth early enough (which always happens in the wild), they lose this capability and die if impregnated later. Some doctors thought it a good idea to try to emulate this in humans by cutting the cartilage there instead of doing a cesarian section, but this causes permanent problems, as in humans the joint does not reattach. Notoriously, for religious reasons some doctors decided to do so anyway, since cesarian section reduces the number of pregnancies a woman can have, which they regarded as more important than being able to walk easily and being continent.
Prenatal development research posits that natural birth is a required “early training experience” and that a lack or disruption of that collaboration between mother, environment and (already conscious) baby during pregnancy and during birth (like cesarean) may result in various psychological deficiencies/difficulties later in life.
See eg.
The Emotional Ramifications of Being Born in a Cesarean Delivery (2017) https://birthpsychology.com/wp-content/uploads/2024/09/liVQo...
Cesarean childbirth and psychosocial outcomes: A meta-analysis. (1996) https://psycnet.apa.org/record/1996-05270-009
Second link is pretty dated and I wonder if more recent studies back this finding.
Orovou, E., Antoniou, E., Zervas, I., & Sarantaki, A. (2025). Prevalence and correlates of postpartum PTSD following emergency cesarean sections: Implications for perinatal mental health care: A systematic review and meta-analysis. BMC Psychology, 13, Article 26. https://doi.org/10.1186/s40359-025-02344-5
Shen, X.-Y., Wang, J., Zhang, W.-N., Zhao, M., Ju, J., Li, X.-Y., Lu, Q., Wang, B., & Zou, L.-P. (2021). Cesarean section due to social factors affects children’s psychology and behavior: A retrospective cohort study. Frontiers in Pediatrics, 8, Article 586957. https://doi.org/10.3389/fped.2020.586957
Hemminki, E. (1991). Long term maternal health effects of caesarean section. Journal of Epidemiology & Community Health, 45(1), 24–28. https://doi.org/10.1136/jech.45.1.24
Handbook of Prenatal and Perinatal Psychology: Integrating Research and Practice Editors: Klaus Evertz, Ludwig Janus, Rupert Linder https://doi.org/10.1007/978-3-030-41716-1 Publisher Springer Cham 2020
[0] https://en.wikipedia.org/wiki/Evolution_of_the_eye#Origins_o...
Of course you could ask why sperm is so temperature sensitive in the first place...
I'm dreading the horror of genetic manipulation it would open. The gene editing craze feels like it is right around the corner.
I still remember this bit from school and various pop-sci book, but is it actually true? Is there really some group of neurons in the brain somewhere that actively tries to restore the "raw" visual information that was blocked by the blind spot?
Thinking of ANNs, I felt it was more realistic that higher layers in the visual cortex are mostly only using the visual information to find patterns anyway, and that they're robust enough they can still find those patterns without the data from the blind spot locations. (As long as a pattern isn't fully contained within the blind spot regions of course)
An analogy would be a QR code reader that can still parse the encoded information if a part of the QR code is missing - but it won't actually "reconstruct" the missing sections to do this.
But I don't know if it really works like this.
The problem with inpainting is that it suggests there is a generator that knows how to fill in that spot before the "witnessing" part of the visual system then gets to work. This is perhaps best thought about from a more extreme example of dreamining: witnessing visuals with the eyes complete closed. In short, the visual system isn't like a projector screen with the finish fixed-up image that some interior witness views.
I believe that most researchers have a very different model, that of the controlled hallucination. What we experience isn't the photons hitting the array of rods and cones like a 2D array of pixels. Instead, we have an internal model of what we are looking at and visual input is there to provide feedback to keep the model of the world updated. The blind spot isn't experienced because we aren't looking at the 2D grid of pixels -- our model is coherent, and the presence of the blind spot simply means that no corrective feedback comes from that area of that one eye.
One compelling bit of information is there while there are neurons feeding processed visual information forward into the brain, there are more feeding back from that area to the visual system. That is, the the visual system is providing error signals and not the image we are experiencing. When something not predicted appears, the visual system sends forward information guiding the internal model to be updated.
Have you ever had the experience where you have been asked to close your eyes and put into a novel environment before then being allowed to open your eyes? It takes less than a second, but you can feel a moment of disorientation while your brain builds that world model. Another way is via some optical illusions (Necker Cube) or Escher drawings. You can look at a part of the drawing and everything is fine, but then as you change your focus there is a transitory feeling of unease as that world model is in flux as it tries to resolve the new visual input with the model it had been using.
Fascinating, I didn't know that. Thank you!
There are dedicated optical illusion/explainers that give you the experience of the brain patching over the space with neutral background, even if there's something there, like a symbol or a star.
So if it's something featureless or continuous, like a wall of your room that's a solid color, or a sheet of college ruled paper, the pattern can just be continued.
That said I would stress there's limits to how much of that you can do just by pattern extrapolation as opposed to deriving images from distinct and specific information in a given region of the visual field. You have to know enough about a stretch of visual space to know that it's appropriate to spread a pattern over it, and that's the thing the blind spot doesn't know.
- Blind spot where the optic nerve exits the eye
- Saccadic Suppression (new to me!)
- Panum's fusional area (how close the overlapping images of your eyes have to be to each other to get merged into a unified image)
- The wagon wheel effect
- trichromatic vision (obvious but important because it easily could have been different)
- The foveial field, the central part of vision that's extremely precise, while things increasingly further away from it are blurry
- specialization in peripheral vision, (eg better sensitivity to starlight, as well as better sensitivity to flickers and motion)
Add those all up and you get a bunch of specific but contingent properties of visual experience. Some people of a certain philosophical frame of mind like to imagine that we inhabit a kind of pure mental experience detached from the physical world, but even if you think you're making no assumptions about the empirical world, all of these contingent facts show up, which make a lot more sense as being the products of biological structure.
The desire to put it this way... the underlying assumptions like "pain is not good", and so on... is ideological, not scientific.
Complete baloney.
But the explanation of crowded tooth being ascribed to evolution is completely false. If one dug around literature even a teeny bit one realizes that many hunter gather groups even today have a a full set of tooth perfectly aligned in the jaw. Dentists, Weston A. Price about a century back and more recently John and Mike Mew (father/son so the same last name) come to mind who tell a different story from the mainstream evolutionary explanation for crowded tooth.