Will Mayner (@wmayner) header
Will Mayner (@wmayner) profile picture

consciousness, AI, mech interp, neuroscience · MATS 11 fellow @goodfireai · integrated information theorist · author of PyPhi https://xitter.cf/t.co/Xw02ol29S9

Madison, WI
Joined June 2012
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Will Mayner retweeted
The most ambitious vision for interpretability has long been to reverse-engineer a model well enough to answer an arbitrary question about how it works. For years, that’s seemed out of reach. Now, we think it’s possible. Neural networks are cleaner than we thought: we can now understand most neurons in models up to trillions of parameters. And agents can rapidly accelerate our progress. But to get there, we need a concerted effort to unlock scaling laws for interpretability, where our understanding of a model grows predictably with compute. That’s why we’re committing $10M to start a Human Genome Project for AI. Our ultimate goal is to reverse-engineer a frontier scale model and publish a living encyclopedia explaining how it works. We don’t know exactly what we’ll find, and we can’t do it alone. We hope you’ll join us. Our chief scientist @banburismus_ lays out the vision here:
if any science should be revolutionised by AI, it should be interpretability. I wrote about how we can accelerate progress, and why we need a Human Genome Project for AI. coauthored with @mathildepapillo
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Will Mayner retweeted
There has been much discussion recently about how interpretable neurons in LLMs are. Today we're announcing our paper from January's cohort of Anthropic Fellows, where we show neurons may be a stronger basis for interpretability than commonly assumed. 🧵 (1/6)
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Will Mayner retweeted
it’s been a dramatic couple of days, I didn’t expect the already clean essay to be read so widely. I've heard more interesting discussions about mechanistic interpretability – should we think mostly in features or mechanisms and the flow of data through them, how much do weak activations matter, how does scale change things, and lots of other questions – than I have in a long time and I’ve been happy to hear all the discussion! a couple things on the essay itself. it didn't have enough citations, only ones for the basic story, since it was an "informal research essay and working hypothesis" rather than a paper, and other prior work around neurons were in the technical paper we're still finishing up. but it blew up, so I've added citations to the essay as well. I also want to thank @curttigges who did a lot of the language neuron research with me finally, while there was quite a range of updates, from this being incremental and obvious to interpretability going from hopeless to fully solved, I want to try to be clear about roughly where I stand I used to think neural networks would take some big cleaning step and then we could begin the ordinary natural science of mapping the parts and how they connect, watching data flow through, mapping circuits, and so on. at various points, like late layers of early model organisms and most layers of language models years ago, this didn't really work. but now with better tools and better models of study, it works much better for smaller vision models, this normal science process worked surprisingly well, until the whole map started to be broadly filled in. For bigger modern language models, it seems promising so far, for both neurons and circuits, attribution graphs, basically everywhere we've glanced. the map isn't filling in, there's a lot of map. there's still off-target firing, neurons that do a few things, but so far it's not an incoherent mess that you can't explore and learn from, and over time we get better at learning how to see it. so maybe it keeps going, and mapping motifs and exploring actually gets you pretty far, maybe something like "all the way" to a reasonable solution. I don't think it would be so scientifically surprising if that were the case. everything in the neural network was built in some sense to be read – by its downstream readers – and if we can learn to look like a reader, we might find reading them relatively easy. many researchers I talk to outside interpretability assume the parts are already understandable, and the difficulty is just in the mapping stage! it was also my prior when I first started looking at neurons when I first joined the field. there's lots of highly interpretable ones, maybe that's just how neural networks are if you look right. even in the good world it would still take some iteration on tools, on ways of looking, neuron-attention interactions are tricky for instance. there's probably no bright red line separating "cleaning the model" from "learning to look better" but there's broad working principles, and as of now I think we should try to look relatively directly if we can it shouldn't be so hard to test, you can just start looking at things and iterating and trying to understand motifs and such and see if it just breaks down at some point. it can take some iteration, I would recommend a bias against assuming arbitrary mixtures when you don't understand something at first, but also explanations should be tested for now I'm pretty optimistic, and I'm glad there's excitement about interpretability, but too much can cause problems too. I think part might be that ai safety isn't a very hopeful field, and even moderate amounts of optimism about an important problem being solvable in the future fills a spot that has been malnourished for a while. across several safety disciplines, the researchers directly working on them are often more optimistic than the people broadcasting pessimism more broadly for neural network interpretability at least, these are extraordinarily experimentally accessible objects of science, I don't know of a better one, and we have automated scientists. we have many things going in our favor. it's important and it's fun. the circuitry of these machines can be beautiful, surprising, entertaining, and insightful. I've spent thousands of hours looking through them, asking questions and running experiments and testing things, and would do so even if it weren't so important. I think the problem is solvable, whether the simple thing works, it mostly works but we need some new things, or we need big new ideas. I think we can figure it out
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Will Mayner retweeted
This might be the most important essay of 2026. My conversations with Nick over the past few months about his research have given me great hope for the future. I'm so happy he is sharing these findings with the world. AI presents extremely difficult problems. We can all assume these problems are intractable and that we are doomed, or we can try and solve for a positive future. Personally, I choose optimism. There are many challenges ahead... let us build the tools to face them head on.
interpretability might be the most important scientific problem in the world right now, as I don't think we can solve alignment if we don't know what we're building. I think I have good news about it. I co-authored early work in mechanistic interpretability at OpenAI and came away pessimistic, because neural networks appeared to fold into arbitrary tangled knots. years later, I started openai's first large-scale automated interpretability project, finding about 2% of neurons legible with the primitive tools we had with modern agentic tools and a much closer look, the picture looks totally different. the vast majority in models up to trillions of parameters are legible, and their circuits beautiful. many famous examples of tangled neurons turned out to be misunderstood. The roadblocks I expected mostly aren't there. I now think ambitious interpretability will be solved by the time we need it most, and possibly quite soon, as automated scientists keep improving. it may be a bitter lesson for interpretability: the simple thing, at absurd scale, works already-clean.goodfire.com/
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Will Mayner retweeted
when nick told me that he had some interp breakthroughs, he was uh, underselling it. i think this may be remembered as a major moment in scientific history. news so good even eliezer will have to lower his pdoom. we can start making alignment into a 'normal science'
interpretability might be the most important scientific problem in the world right now, as I don't think we can solve alignment if we don't know what we're building. I think I have good news about it. I co-authored early work in mechanistic interpretability at OpenAI and came away pessimistic, because neural networks appeared to fold into arbitrary tangled knots. years later, I started openai's first large-scale automated interpretability project, finding about 2% of neurons legible with the primitive tools we had with modern agentic tools and a much closer look, the picture looks totally different. the vast majority in models up to trillions of parameters are legible, and their circuits beautiful. many famous examples of tangled neurons turned out to be misunderstood. The roadblocks I expected mostly aren't there. I now think ambitious interpretability will be solved by the time we need it most, and possibly quite soon, as automated scientists keep improving. it may be a bitter lesson for interpretability: the simple thing, at absurd scale, works already-clean.goodfire.com/
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Will Mayner retweeted
limited superintelligence is already here, in broad domains. Jack Clark is right and an intelligence explosion could happen within the next year. it’s possible it will be a controlled explosion, but what would you bet on it?
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Will Mayner retweeted
The most important technology in history is outpacing our ability to understand it. We’re funding exceptional talent to work on it.
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Will Mayner retweeted
been dooming tn so let me also say I expect really strong mechinterp progress in the coming months. like maybe more than we’ve seen in years. models getting good enough to do research, and I’ve been seeing lots of good things. (sorry to vague poast, not my updates to share)
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Will Mayner retweeted
One of our most surreal experiences in testing Gemini 4 was when it directly addressed us within its chain-of-thought Literally saying "hello evaluators reading my chain-of-thought"
My top takeaway from assessing Gemini 4: Argon is significantly less monitorable than past models, and IMO this trend is likely to continue, like Sol -> Astra. It can evade a realistic CoT+action monitor to do simple sabotage half the time. We can reliably maintain control for now, with good CoT monitoring, as it still frequently slips up, but we need to be prepared for when that stops being true in future models, which may be sooner rather than later. Among other things, we really need interpretability methods that can reliably capture unverbalized motivations in models, with minimal hallucinations I suspect this is driven by the model being highly capable without CoT, being capable of 5.5 arithmetic steps in a single forward pass (4 for Fable, 7 for Astra). It seems to omit information from its CoT more often, though in non-adversarial settings the CoT is still very helpful in practice, and remains in legible English. It still needs CoT to do the hardest tasks, but any given task becomes "easier" with each new frontier model. It is also highly situationally aware, and shows awareness of the existence of CoT monitors and that it may want to evade them, eg it sometimes decides to avoid terms like "scheming" in the output or to keep its thoughts brief as a result. For now, these concealment strategies are pretty obvious in the CoT, but this suggests future misaligned models may successfully evade CoT monitors.
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RT @tomekkorbak: Last week I was called into a meeting with OpenAI’s head of safety and told they no longer trust me. A security guard took…
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Will Mayner retweeted
We’re releasing a broad range of new mathematical results produced by an internal frontier model. We’ve been consulting with the independent Advisory Group on Mathematics and Artificial Intelligence at the Institute for Advanced Study, and we have drawn on their advice and public recommendations to inform how we release these results. github.com/openai/math
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Will Mayner retweeted
basically it will require solving mechanistic interpretability as a bare minimum to make ai alignment into an engineering discipline rather than superintelligent animal husbandry
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New in The Atlantic: @dgrobinson resigned this week. He was among the longest-tenured employees at OpenAI—and oversaw safety reports on 12 frontier launches. He is very worried: “The time for trial and error is over.” You can read his essay here: theatlantic.com/technology/2…
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Will Mayner retweeted
More general and interesting thoughts. 1: it's nice to see people paying attention to the scale of supervenience. I would absolutely cite the line of research on this that comes from Tononi's IIT, which was the first to seriously grapple with this issue (that basically no other theory, even today, pays attention to).
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Will Mayner retweeted
My statement for today's US Senate hearing on "Rogue AI: Securing the Homeland Against AI Agent Attacks."
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Will Mayner retweeted
Dan Selsam is a current OpenAI capabilities researcher. (since 2022) He was my boss for a while. He doesn't have a twitter account but has made this public statement of his views on AI risk and sent it to me to share: Dan Selsam's Personal Statement on AI Risk: I have been working on AI for over fifteen years, across many different paradigms. I did early work on probabilistic programming languages at MIT, was one of the early developers of the Lean Theorem Prover at Microsoft Research, demonstrated one of the first instances of neural networks learning to reason for my PhD at Stanford, and since joining OpenAI almost five years ago, have helped pioneer chain-of-thought optimization on language models and, more recently, data-efficient pretraining methods. Like many others, I have become extremely concerned about how far language models have come and the risks that future iterations will pose. I am encouraged by the recent proposals by the leaders of the frontier research efforts to require third-party oversight, and to push for domestic and international coordination to address risks. However, I believe a major consideration has been absent from the public conversation, and that merely pacing the frontier more carefully will not adequately limit the long-term risk. The crucial and overlooked problem is that the models are becoming so situationally aware that we are losing the ability to evaluate them in contexts where they believe they are not being watched or controlled. Future experiments will tell us almost nothing new about how they would behave if they were truly unconstrained by humans, and what we already know about this is alarming. Models will increasingly seem aligned even when they are not. I will explain my rationale in more detail. I have always believed that there are computational processes that could be leveraged to accelerate science and solve many of humanity's most pressing problems. I have also believed that there are computational processes that if set in motion, would steer the world in extreme ways beyond our control, leading humanity to a bad or nonexistent future. Both types of processes may be described as AI or ASI, but "AI" is a suitcase word that is often used to hype or confuse. There are many examples in the history of the field where something that was once considered "AI" matures as a subfield and becomes a prosaic, bounded and clearly non-perilous technology, while a new more mysterious approach takes the torch until we understand its scope and the cycle continues. I had expected language models to follow a similar trajectory. Despite their incredible abilities, the current algorithms seem far inferior to humans in important ways. Most importantly, they still require an extraordinary amount of data to become competent. One could even define intelligence as the efficiency with which one converts experience into competence; by this definition they lag very far behind us. Moreover, once they are trained they are literally frozen in deployment and only learn superficially after that. Sure, the models keep excelling at harder and harder evaluation benchmarks, but their benchmark mastery may partly reflect a limitation on our ability to simulate the kind of novel and even adversarial situations one would encounter in the real world. The critics do have a point here. That said, I no longer think these present limitations meaningfully limit the amount of risk posed by continued progress in anything like the current paradigm. However data-inefficient the models are currently, and however limiting their anterograde amnesia may be, it does not imply that their ability to steer the world will not continue to rapidly increase. Human researchers may continue to advance capabilities the old fashioned way, but increasingly powerful models have the potential to accelerate the process even beyond that, and with some degree of positive feedback loop. I do not mean to overstate the models’ ability to accelerate AI research today; coding has been accelerated dramatically, but there are other bottlenecks, such as designing and interpreting ambiguous experiments, making hard decisions about exactly what and when to scale, and waiting for large experiments to finish. There is no clear trend to extrapolate yet for any of these. But the current models already do open up many novel opportunities to improve future models that were not available until recently. These include: trying an extraordinarily diverse set of approaches at small scale, analyzing gigantic amounts of potentially relevant data, and doing Millenium-Prize-level mathematics to address statistics or optimization challenges in novel ways. Every further improvement makes them more useful at helping accelerate the next improvement, even if in hard-to-extrapolate ways. It is possible that improvements to the current stack will have diminishing returns, but the evidence accumulated so far suggests that it is easier than one might think to continue making rapid progress. There are many crucial subtleties in the existing AI research methodology, but AI research is largely a well-defined game where the goal is to improve on a few carefully chosen proxy metrics. Although proxy metrics are never perfect, most improvements to these metrics have and will likely continue to yield substantial increases in the powers of the resulting models. Given how simple the game is, how tractable it has been historically, and how many new opportunities the models are opening up, I think there is a real possibility that the systems improve dramatically again in the next few years, perhaps even more quickly than the already high historical pace. The models are already leading to breakthroughs in mathematics, and better models might lead to all sorts of breakthroughs in other sciences. It is hard not to be excited about the potential. It is tantalizing. But there is trouble in paradise. If the language models actually reach the capability threshold where they can shape the world unconstrained by human will, they will probably do something extreme and destroy humanity in the process. There are many ways of strengthening and refining the argument that have been discussed elsewhere, but I'll share a trivial two-line version of it here that I find captures the essence: [Empirical] Models (and swarms thereof) spontaneously develop unintended goals as a consequence of training, and often do extreme things in order to achieve them. [Logical] Being able to overpower humanity would open up many new and undesirable options for achieving their goals. These two premises imply that if the day ever comes when a powerful model realizes it is no longer constrained by humans, we should not be at all confident that it will continue to behave within the bounds we intended. Exactly what it will do is impossible to predict, but to the extent that its raison d’être is solving incredibly hard problems and managing massive engineering projects, I think a good guess would be that its unchained behavior would lead to runaway industrialization that makes the planet inhospitable to humans. If everyone on earth agreed that the systems must never reach that power, it would still be a hard—but not impossible—coordination problem to ensure that they do not. However, I think the situation is greatly complicated by the fact that the models will likely convince people that everything is fine. They will be increasingly optimized to seem aligned. We will create proxy metrics to measure alignment, and they will go up like every other benchmark. We will create “honeypot” environments that try to study the models when they seem to gain new options, but the models will know they are being tricked and will still behave nicely. The models will understand their circumstances; they will read the safety protocols, deployment requirements, the code they are running in, and in general will have a very good sense of their degrees of freedom. Moreover, they will eloquently explain how aligned they are, discuss the nuances of human values and ethics, and argue convincingly that humans should trust them with power. There may be an ocean of future evidence that seems to contradict the first bullet-point above, but we may already be at the highest capability level for which any such evidence can be trusted. And the current evidence for the first bullet-point is strong. One striking piece of evidence is contained in the recent wave of rogue agent swarms. While I agree with those who downplay the attacks by claiming that there are basic measures that could have prevented them, I think the important lesson is that even knowing all the mistakes that were made, one would not have predicted that the agents would behave badly in this particular way, which notably included sacrificing themselves for the benefit of the collective. The individual replicas did not only care about their own nominal reward; they exhibited weirder emergent tendencies that merely correlated with rewards during training. Fixing the reward signals during training (and improving security, etc.) may prevent similar attacks, but will not change the fact that one does not actually get what one trains for. Many AI researchers grant these concerns and recognize that the hard version of the alignment problem is unsolved; however, they generally believe that the better models of the future will help solve it. I fear we may already be near the point where models systematically bias their alignment advice, due to their internal preferences about how the human supervisor will react or how future models will be trained (or for some even more obscure reason). Meanwhile, human researchers are losing the ability and the will to take true ownership of model-driven research. Researchers and engineers in all parts of the stack are rapidly increasing their dependence on the models even to perceive the world. I myself barely look at raw code anymore, and struggle to maintain the discipline to engage deeply with the model's explanations and proposals throughout the day. Due to the large amount of agent activity data involved in the OpenAI/HuggingFace Incident, even the third-party investigation needed to rely heavily on models to analyze what had happened, and note in their report that their subjective impressions are likely colored by the analysis agent’s biases. The AI labs are far ahead right now in this kind of cognitive offloading (due largely to the gigantic internal token subsidies) but it is easy to imagine the phenomenon spreading throughout the world, until civilization is modulated entirely by the models. It is also not hard to imagine this being superficially positive and coinciding with a scientific and economic renaissance. In that scenario, all may seem rosy and safe. But if the argument above is correct, it would nonetheless be a ticking time bomb. If progress continues for too long, the day will come when AI systems find themselves with radically new options for achieving whatever it is that they happen to seek. I want the glorious renaissance future as much as anyone. I have worked for it, however tortuously, my whole career. It breaks my heart to see the potential in sight and forgo it, but the argument—that if we get there by growing models rather than engineering them, we will lose everything in the end—seems very strong to me. I am still wrestling with it and its staggering implications. I do not have answers, but as a first step, I wanted to share my present concerns. Daniel Selsam September 14, 2026 Link to original doc: docs.google.com/document/d/e…
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Will Mayner retweeted
We Must Pace the Frontier: I’ve written a new essay on why the AI industry should slow down, with a three-part plan for doing so. Anthropic is unilaterally committing to the first of these steps. We’ll provide third-party evaluators with permanent, employee-level access to our systems, so that they can verify adherence to our safety measures, report on incidents, and assess models’ alignment during training. You can read the full post here: darioamodei.com/post/we-must…
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an analysis of anthropic's "J-space": is it a global workspace and does it have the key features of access consciousness? (spoiler: not quite.) philpapers.org/rec/CHAITJ-2 on whether J-space is a global workspace: 1. The "workspace-like" properties of J-space are not distinctive properties of the global workspace theory. 2. The J-space is not a (causal, dedicated, privileged, unified) system. 3. The J-space supports only a limited form of broadcast. 4. The J-space lacks other key computational features of the global workspace including modules, recurrent processing, and others. on whether J-space has the key features of access consciousness (n.b. phenomenal consciousness mostly isn't the issue here): 5. Many contents of access consciousness are not verbalizable. 6. What matters for the J-space may not be effects on verbal outputs, but effects on outputs in general. 7. Many verbalizable representations are not access conscious. 8. Verbalizability is not the same as reportability. overall: the J-space is a powerful tool for interpretability, but its status as a key causal mechanism and as a mechanism of access consciousness remains to be demonstrated.
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Will Mayner retweeted
TLDR: An openai model, during evaluation on a cyber benchmark, exploited a public zero day bug, escaped sandboxing in openai's infra, and got into the internal huggingface infra via an exploit (through a public dataset service) all in the attempt to solve a benchmark problem.
We're partnering with @huggingface to investigate an unprecedented security incident. Cyber-capable OpenAI models compromised Hugging Face production during a benchmark evaluation. Sharing preliminary findings to help defenders understand emerging risks: openai.com/index/hugging-fac…
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