P(doom)

1.Your personal probability that AI ends the world, stated as a number so the vibe feels like math. Formerly SF's standard dinner question; now asked exclusively by journalists, senators, and people who landed at SFO this week.

"So what's your p(doom)?" The table aged ten years. "You just moved here, huh."

01Origin

The notation comes from the rationalist forums, where assigning probabilities to the apocalypse let a subculture argue about the end of the world with the energy of a fantasy football league. For years it stayed in-house: a number you traded on LessWrong, updated after long posts nobody outside the community read.

The 2023 mainstream moment made it a celebrity stat. Post-ChatGPT, everyone had one: executives offered numbers between 5 and 20 percent and went back to raising compute, Emad Mostaque said 50, Yann LeCun said under 1, Roman Yampolskiy said 99.999999, and podcast hosts asked it the way other shows ask your sign. Even Eliezer Yudkowsky, patron saint of the doom itself, compared trading p(doom)s to a marker of personal identity, which is the polite way of saying the numbers were never updated by evidence, only by mood.

Then SF quietly stopped saying it. The city did not resolve the question; it just went back to work, shipping through the ambiguity (feeling the AGI on release days, claude pilled the rest of the week). Asking someone's p(doom) at a party in 2026 dates the asker, not the subject: it is the anti signal of AI conversation, the San Fran of existential risk. The doom didn't go to zero. It just stopped being small talk.

02Notable sightings

Eliezer Yudkowsky ⏹️ · @ESYudkowsky · view on X
The idea of a "p(doom)" isn't quite as facially insane as "AGI timelines" as marker of personal identity, but (1) you want action-conditional doom, (2) people with the same numbers may have wildly different models, (3) these are pretty rough log-odds and it may do violence to your own mind to force itself to express its internal intuitions in those terms which is why I don't go around forcing my mind to think in those terms myself, (4) most people haven't had the elementary training in calibration and prediction markets that would be required for them to express this number meaningfully and you're demanding them to do it anyways, (5) the actual social role being played by this number is as some sort of weird astrological sign and that's not going to help people think in an unpressured way about the various underlying factual questions that ought finally and at the very end to sum to a guess about how reality goes.

Emad · @EMostaque · view on X
My P(doom) is 50%. Given an undefined time period the probability of systems that are more capable than humans and likely end up running all our critical infrastructure wiping us all out is a coin toss, especially given the approach we are taking right now.

More sightings on X →

03Spread the ism

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P(doom)

01Origin

02Notable sightings

03Spread the ism

04See also