(Funnily enough, if we're invoking ISO 8601, it also defines that weeks are anchored to a year by whatever year their Thursday is in.)

I used to go by Monday–Sunday, but I've grown into a firm believer of Sunday–Saturday. I'm going to start my own standards organization, and we'll have incredible tea, open access, and civilized boundaries for weeks. [relevant xkcd here]

Fair point that there's some ambiguity, albeit not caused by an inherent ambiguity between "this" and "next". I'd just invoke "next Thursday" in that situation because it's the same regardless of apostasy.

Internal consistency test:

It's May 2024. You're talking about February 2025. Given the choice only between "This February" and "Next February", which do you call it?

Edit: In fairness, I realize I fail this consistency test too. If, in January 2024, someone said "Next February", I'd assume they're referring to February 2025, since I would only ever say "this February" to refer to February 2024 to avoid confusion (even though February 2024 technically is "next February"). Urgh, my brain. "You're making me think about this way more than I ever have. Come with me!"

I disagree with the last part of your statement. If you say 'next thursday' on a Friday, it still means the second Thursday away. This Thursday always means the next upcoming, so next Thursday should always mean the one following 'this Thursday'. The weekly period rolls with whatever day you're talking about.

If next was the next occurrence of the day you’d be saying “next Wednesday on a Tuesday” and be talking about tomorrow, which is frankly ludicrous. I’ve also never heard anyone use a rolling week for “this” and this is such a funny conversation to come up because I literally had this confusion last Sunday (not this previous Sunday, as in yesterday, also note that this lines up well with using “last week”), because I was talking with several Venezuelans, a Chilean, a Mexican, and a Salvadoran, along with some Americans and this exact confusion came up but not because it was a rolling week, or because next means the next occurrence, but because they considered the week to start on Monday, not Sunday. So “this Thursday” meant the previous Thursday, since it was part of that week. Next Thursday meant the coming Thursday (the part of the next week).

I mention the nationalities because it’s pretty uncommon to start a week on a Sunday like Americans do.

Weirdly I looked it up and the internet says those countries start their weeks on Monday but that sure wasn’t what the people I talked to thought. 🤷

three days hence

What the fuck. 😭 But "next Thursday" clearly has a well-defined 7-day period. Given a bus stop with 20 minutes between buses, the "next bus" doesn't just start arbitrarily applying 10 minutes after the last bus left. Who would use it like this??

This doesn’t make sense from a linguistics standpoint though. So next Thursday is the Thursday this week, but next week isn’t this week, it’s the week after this one. So what’s the Thursday in that week, the next next Thursday? It just doesn’t work.

Anything in this week (Sunday-Saturday or Monday-Sunday) even stuff from a few days ago -> this .

Anything from last week -> last

Anything in next week -> next

It’s incredibly simple and it’s logically consistent and it works in every situation unless you are talking to someone from a different country that uses a different starting day. And even then it works the majority of the time.