Hold tight, barachiki has been doing some historical musing:
Let’s start here. The funny thing about Sherlock Holmes is that, despite 150 years of scholarship, adaptations, annotations and theorizing, you’ll still meet someone whose Holmes take is somehow even more unhinged than yours (tone indicator : affectionate). There are simply too many flavours of insanity.
Also, ACD wasn’t especially consistent with his own characters, so generations of fans have cheerfully built elaborate theories to explain all the contradictions.
Mary called Watson “James” one time, leading fans to say James was based on his middle name Hamish and Mary was using it as a pet name,
Mrs. Hudson was the but was accidentally called Mrs Turner in one story, so fans decided Mrs. Turner was a neighbor or a temporary cook hired to assist her.
What I’m trying to say is that headcanons have been around for aaaages. Some just more agreed upon than others.
Ok, getting back on track: When I was at university I think we were studying The Blue Carbuncle, I was internetting and stumbled across an article strongly pushing the idea that Watson had accumulated a whole bunch of wives throughout the stories. Mostly casual references and whatnot became clues, and we ended up with a whopping six wives. Through his evidence, he concluded that Watson's final wife was .... Mrs. Hudson. The evidence was... let's call it creative.
(I tracked it down. It's from 2002, and yes, it really exists: Counting Watson's Wives.)
I absolutely loved this bonkers theory (again, tone indicator: affectionate). My favourite part is that the author doesn't merely suggest the possibility. He confidently concludes:
"And on his sixth try, it looks like Watson finally got it right."
Nowadays we'd probably say, "here's my headcanon" "I've got a meta about that" or whatever. This guy looked at the Canon, built a board and connected some red string from of timelines, throwaway references, and whatever Victorian train schedules, and declared: "No, actually. This is what happened. You're welcome."
And honestly? That's what makes it so awesome.
Sherlockians have been doing exactly the same thing for ages, even in the face of so many plot holes and inconsistencies, they will pull things together and glue them into a way that makes sense for them.
Yeah this is an article from 2002 (ish?) but it cites reasoning from old ACD fandom lore throughout the whole thing. It's a nice reminder that tumblr fandom didn't invent elaborate theories, obscure evidence chains, or double down in the face of overwhelming uncertainty. We've always been like this.
Today it is just someone explaining why the secret fourth episode definitely exists, TJLC is real, and how Mary is actually Moran.
Different vocabulary. Same energy.