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.

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.