Published on September 17, 2025 9:10 PM GMT
It’s meetup month! If you’ve been vaguely thinking of getting involved with a some kind of rationalsphere in-person community stuff, now is a great time to do that, because lots of other people are doing that!
It’s the usual time of the year for Astral Codex Everywhere – if you’re the sorta folk who likes to read Scott Alexander, and likes other people who like Scott Alexander, but only really can summon the wherewithal to go out to a meetup once a year, this is the Official Coordinated Schelling Time to do that. There are meetups scheduled in 180 cities. Probably one of those is near you!
This year, we have two other specific types of meetups it seemed good to coordinate around: Celebrating Petrov Day, and reading groups for the recently released If Anyone Builds It, Everyone Dies.
And, of course, if you aren’t particularly interested in any of those things but just want to (re)connect with your local LessWrong meetup for whatever events they’re currently hosting, you can view our usual community map filter for the “LW” events.
If Anyone Builds It reading groups
MIRI’s new book launches this week. It’s particularly valuable if people buy copies of it by Sep 20th (to make it more likely to appear on bestseller lists, which in turn make it more likely to get press and get into the mainstream consciousness).
The book is a (relatively) succinct articulation of the core arguments for AI being likely to destroy humanity. It’s a pretty big topic to think through, and it seemed valuable to encourage public (or semi-public) reading groups where people can read and discuss it together.
Some considerations:
- The book is short enough it might make sense to have a single meetup for discussing it, but, you might also consider holding multiple meetups that discuss a given chapter, or, group of chapters.If you’re discussing one chapter per session, you might consider explicitly scheduling an optional opening hour for reading the chapter, for people who’d have trouble making time but would enjoy reading it quietly with friends.
Click here to create a lesswrong event for an If Anyone Builds It reading group for our frontpage meetup map.
You can buy copies for your group here.
Note, if you would like some support getting your reading group running (i.e. suggested discussion questions, and potentially financial help buying the books) you can fill out this form.
Petrov Day
September 26th is Petrov Day – a day when humanity came close to the brink of nuclear war. Stanislav Petrov worked in the Soviet military, and received an alert indicating a nuclear attack. But the information was suspicious – the alert reported only five warheads incoming. His orders were forward the report of a nuclear attack to his superiors, who may likely have retaliated and initiated a large scale nuclear war.
Instead, he reported it as a false alarm.
(It was, indeed, a false alarm, possibly triggered by a flock of birds)
On LessWrong, Petrov Day has come to be celebrated as a holiday about existential risk more generally. There have been many ways of celebrating Petrov Day. But the version I’ve found pretty meaningful as a holiday ritual is Jim Babcock’s hourlong ceremony, designed for 6-12 people. (If you have more people than that, he recommends splitting up into multiple subgroups who each fit around a table).
It involves printing out some booklets and some candles, and taking turns reading through the story of Petrov Day (along with context from throughout human history).
In previous years, Jim and/or I have one a mad last-minute scramble to remind people and try to buy candles. (Note: there’s a bunch of ways you can screw up ritual candles).
This year, we thought “let’s try to help people think about this more than 2 days in advance.”
If you want to host a Petrov Day ceremony, you’ll want some supplies. There ceremony involves 8 candles. Two of them don’t actually get lit, and represent futures where humanity flourishes or extinguishes itself.
For a mix of aesthetics/practicality, I recommend getting these candles, with these candle holders. (I personally like having two fancier candles representing the flourishing and extinction futures, such as this one for flourishing and this one for extinction)
You’ll also need to print out a 8-12 copies of this booklet for readings. (I recommend finding a local Fedex or similar, to print out several copies, to simplify the process.)
Click here to create a Petrov Day event for the frontpage map.
Meetups will show up on our home page map, for people viewing the site on desktop:
Happy meeting up, happy book launch, and happy Petrov Day. :)
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