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In support of your scepticism I have to say there is something I'm always missing in these discussions about the alleged function of the appendix. That thing that I'm missing is a straightforward description of what are the consequences of patients losing these functions after an appendectomy. Surely there is more than enough population over which to do a case-study observational analysis? So, where is it? What happens to the immunity or gut flora of people who have had their appendices removed? Anything?

This seems similar to asking what happens if you loose a number of parts whose loss does not produce immediately discernible detriment, or perhaps parts whose function may be approximated by something else in the event of a failure.

Of course, it is a perfectly valid question to ask what the effects of losing a part are.

Hence mention of a large population who lost those parts. The actual detriment may not be identifiable in a random individual, but it will show up at scale, as the noise of other confounders will average out.

The article touches on this:

> Studies have shown that infections with the really bad, nasty bacteria C. diff tend to be higher in people who have had their appendix removed.

Thanks, I somehow missed that part. I wonder how those studies controlled for confounding factors — it could well be that a prior tendency to more Clostridium difficile infections is correlated to a tendency to get an appendix infection.

To be clear, I'm not necessarily as sceptical as GP commenter. I'm just surprised that so much talk about the actual function of the appendix appears to centre around theoreticals rather than on clinical data.

> nasty bacteria C. diff tend to be higher in people who have had their appendix removed.

Uh, because people undergoing appendectomy are, almost by definition, more likely to receive antibiotic treatment, which is a far-better documented basis for C. diff infection. This article is catastrophe.

Though I tend to agree with your train of thought, I'm always reminded of the French man who lost 90% of his brain mass yet still had a family a job and lived a normal life by all accounts. The human body can confound expectations for sure.

Sure, but outliers aside, I'd reckon you would see some sort of statistically relevant effent if you take, say, 1000 people, yank out 90% of the brain of half of them, and just watch them go about their day. (If the ethics committee would let you)

You might want to invest in some creative writing for the IRB packet for that one.

He didn't lose his brain mass, it was compressed into a thin shell around his skull.[0] Moreover, his IQ was 75 - I'm not sure ending up in the bottom 5% of human intelligence as a consequence of chronic hydrocephaly is a "normal" life.

[0] https://www.untrammeledmind.com/2018/02/so-his-brains-just-s...

Not normal, but impressive nonetheless.

Nothing you said convinces me that the uvula and appendix have no purpose. I assume that ends of things do come together a lot during development, but why does that imply no importance? Sounds like a classic case of chesterton's fence. and I hate to say it but argument from authority is pretty boring.

Is it an argument from authority or an argument from experience?

Experience would mean he's taken out a bunch of people's appendices and nothing bad has happened. Which still wouldn't prove that the appendix has no purpose at all.

He's a pathologist, so if he has removed someone's appendix they'd probably be dead. Pedantry aside, your point still stands.

I've done a fair number of autopsies and have never even heard of someone ending up on the autopsy table secondary to an appendectomy. I'm sure it's happened, but, on balance, if the docs say you need an appendectomy, they're probably right.

Just making a dumb joke that if it's the pathologist that's the person removing an appendix, they're probably dead already.

Experience can mean a lot of things.

And there is nothing in the article either that convinced you?

Yeah, it convinced me of the opposite. The appendix is probably not useless.

I think you misread GP, they only said the appendix is not an evolutionary mystery, not that it doesn't serve a purpose. In fact, he noted the presence of lymphoid tissue, which makes is useful to the organism, as stated by the article as well.

The main article claims that the appendix is not useless.

I don't think I misread GP:

  "they're just the ends of things that come together."

  [something about cyclops and male pregnancy]

  "Fun stories, completely useless"

At best it's a series of straw man arguments with sprinkles of appeal to authority.

I feel like maybe they didn't read the article and misinterpreted the double-negative in the headline.

GP here (GGP?), I read the whole article.

Mentioning their background is not necessarily an appeal to authority fallacy. It’s just metadata.

> metadata.

Exactly. Sort of like getting a picture and the metadata says "Nikon". Probably that picture didn't come from midjourney.

I read "fun stories" to refer to cyclops, male pregnancy and the deep mystery of the real purpose of the appendix. That's a plausible critique to me, and one which is compatible with the appendix being still useful. Same for the first comment you mention. Yes, it's just the ends of things that come together, but life makes use of that real-estate anyway. It's just not critical, and there is only a slight dent in immunity when removed.

They used paragraphs to separate complete thoughts.

Note, GP explicitly mentions the following in their last paragraph, and make no claims that the appendix is useless:

> This idea that the vermiform appendix is some deep evolutionary mystery is sort of a low point of medicine that occasionally pokes its head up. It ranks up there with male pregnancy, and various birth defects that have given rise to stories of monsters, like Cyclops. Fun stories, completely useless.

So it's like how knit hats often have pompoms to hide the lumpy part where all the threads come together, but like... for bodies?

More like the lumpy part where the threads come together that the pompom is hiding

Is this part of why everyone is so anxious to hear of the baby's first bowel movement? I know it's a sign the plumbing works, but I am not sure I would have included "the plumbing is connected" under 'works'.

I always thought this was for two reasons: one as you say is to show the plumbing works, the other is because not passing the meconium (combination of stuff ingested while in the uterus) indicates other more serious conditions might exist

Newborn bowel movements are also important for preventing more serious jaundice.

There are lots of ways things don't work. The plumbing can be connected up wrong or the pumps can not work.

> Pathologist ... returns 0 when the microenvironment variables ...

Wow, and also informative and funny. This is HN in its full glory!

Sorry for the off-topic.

Looks like it returns 1, to me.

NaN

Returns 1 would be cancer, autoimmune disease, or malformation.

I believe Cyclops myths were inspired by the skulls of dwarf elephants who lived on the island of Sardinia. https://greekcitytimes.com/2023/01/28/cyclops-ancient-greeks...

At first I thought the dwarf elephants would have come as a result of the Zanclean megaflood [0] of 5m years ago, which did cause some odd sized animals like the small dog sized rabbit Nuralagus [1], but the Mediterranean dwarf elephants did not appear until 2.5m years ago [2].

0. https://unchartedterritories.tomaspueyo.com/p/the-zanclean-m...

1. https://en.wikipedia.org/wiki/Nuralagus

2. https://en.wikipedia.org/wiki/Dwarf_elephant

Dwarf elephants have appeared separately in multiple places and times when full-sized elephants got stranded somewhere and their habitat / food supply was restricted. There were dwarf mammoths in the California channel islands until pretty recently (a mammoth presumably swam from the mainland when the sea level was lower and they were one big island).

For more non-elephant examples

https://en.wikipedia.org/wiki/Insular_dwarfism

Even if that's just a seam, so to speak, it doesn't mean it can't evolve, I guess.

So the question is: why do we have a part of the body that seems to serve no purpose besides getting infected? And if it is not, in fact, useless, what purpose does it serve? Logically it should improve survivability more than the occasional infection decreases it, otherwise it should have disappeared, or at least, be different than it is now.

Unless appendicitis is a relatively modern disease and didn't affect survivability significantly and for long enough for evolution to do its work, which is a common hypothesis.

The appendix does not evolve. The organism evolves. Logically, the genes encode proteins that respond to the local microenvironment. And that's it. The cells have no idea where they are, other than subtle cues from their neighbors. Imagine trying to build a city with no localization input except accelerometry. Theoretically, works fine. In practice, eh, there are some odds and ends left over.

I've got the proof of the embryology in my throat. My uvula is partially split. See: https://my.clevelandclinic.org/health/diseases/23943-bifid-u...

As you described, nature just joints the pieces in a best effort and when it goes wrong, its never very likely to grow up to have appendictis. So the absence of anecdotes about failure is a indication of vitality of an element not of any designs.

My question: Did you discover during discection differences on the appendix depending on nutrition? Of course, people usually do have hospital meals in them when they drop by on the stainless steel desk.. none the less.. there might be bits stuck to the inflamed material..

Awesome! Anatomy is so cool. Watching anatomy videos on YT, to me it seems like human bodies are composed of layers of biopolymers. The way all the structures are arranged and the intricacy and clean distinctness of the different layers is incredibly well organized. The human body is an amazing marvel, more so in than out in many ways.

Regarding gut bacteria, can you actually see biofilms of bacteria in the gut? Where do they reside? Or you can't tell with the eye?

Can you put the colon on the blockchain? I might know a guy.