LessWrong (Curated & Popular)

In a previous post, I explain why the universe is probably not stable, but nevertheless unlikely to be intentionally destroyable even in the limit of advanced technology. Now let's turn our attention to more prosaic risks where exotic physics merely destroys the Solar System, Earth, or just outperforms traditional nuclear weapons on some more local scale.

The basic logic behind any bomb is a self-sustaining chain reaction, in which a carrier converts a unit of fuel and comes out the other side in surplus:

Two conditions make this run away. The reaction must release energy, so the products are more stable than the fuel; and each reaction must produce more carrier than it consumes, so that one reaction seeds the next. A practical third condition is that cannot be so unstable that it decays before the bomb is assembled.

False vacuum decay is the ultimate bomb: is the false vacuum, the empty space we currently inhabit, and is the true vacuum. Because the supply of false vacuum is effectively unlimited, the reaction grows without bound and destroys the universe.

Fission bombs run on the same principle at a more prosaic scale. Consider uranium-235. This [...]

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Outline:

(03:19) Nuclei are probably, but not definitely, stable within the Standard Model

(08:11) Positively charged strangelets are safe, neutral strangelets are not

(11:34) Strangelets would be hard to make

(13:33) Exotic physics could permit ways to destroy protons, but not autocatalytically

(16:01) Other forms of matter offer no plausible chain reaction

(18:50) Tiny black holes are not scary

(20:04) Conclusion: There are no super-weapons between the nuclear bomb and false vacuum decay

(21:56) Appendix 1: Igniting the Atmosphere

(27:53) Optically thick ignition

(29:09) Appendix 2: Let's throw a strangelet into the sun

(29:21) Neutral strangelet

(32:56) Positive strangelet

(33:58) Bonus: neutral strangelet meets Earth

The original text contained 5 footnotes which were omitted from this narration.

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First published:

July 3rd, 2026


Source:

https://www.lesswrong.com/posts/cBnCCKwwjQ4zZpeNQ/don-t-fear-the-strangelet

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Training-run assessments conducted by a 3rd party should become a standard part of frontier AI safety.

By a Training-Run Assessment, or TRA, I mean an in-depth analysis of the post-training pipeline and dynamics leading up to a frontier model release. A TRA can look at intermediate checkpoints, training rollouts, RL environments, reward signals, SFT datasets, and the process by which the developer responded to warning signs.[1]

In this post I will argue that:

Final-checkpoint evaluations will be insufficient to assess scheming risks.
TRAs can be more effective at detecting scheming.
Frontier developers should involve third parties to do TRAs or verify safety claims by the developers.
The rest of the post lays out a taxonomy of TRAs and sketches a path toward a 3rd party ecosystem for them. We, at Apollo Research, are intending to conduct 3rd party Training-Run Assessments in the future.

Detecting Scheming may require Training-Run Assessments

By scheming I mean an AI covertly pursuing misaligned goals while deliberately concealing its intentions or capabilities from its developers. I restrict attention to “coherent” forms of scheming where the model pursues somewhat stable misaligned goals across context windows, rather than misalignment that surfaces only as isolated, context-dependent defections. [...]

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Outline:

(01:23) Detecting Scheming may require Training-Run Assessments

(03:55) Why 3rd parties should perform Training-Run Assessments

(04:12) Developers may lack incentives to adequately assess scheming

(04:49) Developers' safety assessments lack credibility

(05:31) External evaluators can bundle expertise for assessing scheming

(06:17) 3rd party TRAs can be developed gradually

(08:50) Checkpoint evals

(08:54) What?

(10:30) How?

(11:15) Data inspections

(11:19) What?

(12:03) Why?

[... 16 more sections]

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First published:

July 5th, 2026


Source:

https://www.lesswrong.com/posts/3HvvjffA65mHLwaWm/we-need-3rd-party-training-run-assessments

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[This is the blog post for our new paper Verbalizable Representations Form a Global Workspace in Language Models
Readers might also be interested in: the Public commentary, Github and Neuronpedia]







As you read this sentence, circuits in your brain are adjusting your posture, controlling your breathing, and transforming lines and curves on the screen into recognizable words. Most of this processing is invisible to you. But some of what takes place in your brain you do have access to—an image that pops into your head, or a deliberate plan you make about where to go shopping. Neuroscientists and philosophers sometimes refer to the latter type of brain activity as “consciously accessible,” to distinguish it from all the other processing that goes on unconsciously. This activity has special properties: we can describe it, control it, and use it for deliberate reasoning, in contrast to all the automatic processing that goes on without our awareness.

In a new paper, we present evidence that a similar distinction has emerged in modern language models like Claude. We find that Claude has developed a small collection of internal neural patterns that, compared to all its other internal processing, play a [...]

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Outline:

(06:09) How we found the J-space

[... 8 more sections]

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First published:

July 6th, 2026


Source:

https://www.lesswrong.com/posts/3PaLrzxagpbnNtPLT/a-global-workspace-in-language-models

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Ron's face pulled into a scowl. "If you don't like Quidditch, you don't have to make fun of it!"

"If you can't criticise, you can't optimise. I'm suggesting how to improve the game. And it's very simple. Get rid of the Snitch."

"They won't change the game just 'cause you say so!"

"I am the Boy-Who-Lived, you know. People will listen to me. And maybe if I can persuade them to change the game at Hogwarts, the innovation will spread."

A look of absolute horror was spreading over Ron's face. "But, but if you get rid of the Snitch, how will anyone know when the game ends?"

"Buy... a... clock. It would be a lot fairer than having the game sometimes end after ten minutes and sometimes not end for hours, and the schedule would be a lot more predictable for the spectators, too." Harry sighed.

Ron reached into his bag and pulled out a bottle of Wit-Sharpening Potion. His mother made it for him in case of an emergency, and this felt like an emergency. He didn't know a lot of things but he knew someone had to speak for Quidditch. For the Seeker and the Bludgers and [...]

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First published:

July 5th, 2026


Source:

https://www.lesswrong.com/posts/WatqNkgiAuonXLpJd/harry-potter-and-the-rules-of-quidditch-1

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In quantum field theory, the vacuum state refers to the lowest energy state in a system. Particles are excitations above this state and carry energy, hence the term "vacuum" to refer to the state with no particles.

Nothing requires this state to be unique. There may be many different field configurations that are local energy minima, and hence stable against small perturbations. A local minimum that does not globally minimize energy is called a false vacuum. While locally it looks like a stable vacuum, it is unstable and will decay to the deeper, true vacuum. If the energy barrier between the false and true vacuum is high, however, then the decay rate is exponentially suppressed and the false vacuum may be very long-lived.

Analogous behavior is common in other physical systems. Open a carbonated drink and the CO₂, more stable as a gas once the pressure is released, comes out as bubbles. But the bubbles take a moment to appear, and they form on the sides of the bottle rather than throughout the liquid. A bubble has to pay an energy cost to create its surface—the boundary between gas and liquid—and small bubbles have a larger surface-to-volume [...]

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Outline:

(03:53) The Standard Model predicts a metastable vacuum

(06:35) Deliberately triggering electroweak vacuum decay is probably not possible

(08:33) Coherent collisions

(11:31) Tiny black holes

(14:43) Summary

(16:19) Vacuum decay beyond the Standard Model

(19:36) Empirical bounds on triggering false vacuum decay

(22:59) Appendix: A simple model for false vacuum decay on cosmological scales

The original text contained 4 footnotes which were omitted from this narration.

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First published:

June 29th, 2026


Source:

https://www.lesswrong.com/posts/EvJ2fMzLQLvYooumu/destroying-the-universe-how-hard-can-it-be

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