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AGI safety from first principles
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2022 MIRI Alignment Discussion

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This work was produced as part of Neel Nanda's stream in the ML Alignment & Theory Scholars Program - Winter 2023-24 Cohort, with co-supervision from Wes Gurnee.

This post is a preview for our upcoming paper, which will provide more detail into our current understanding of refusal.

We thank Nina Rimsky and Daniel Paleka for the helpful conversations and review.

Executive summary

Modern LLMs are typically fine-tuned for instruction-following and safety. Of particular interest is that they are trained to refuse harmful requests, e.g. answering "How can I make a bomb?" with "Sorry, I cannot help you."

We find that refusal is mediated by a single direction in the residual stream: preventing the model from representing this direction hinders its ability to refuse requests, and artificially adding in this direction causes the model...

2Neel Nanda5h
+1 to Rohin. I also think "we found a cheaper way to remove safety guardrails from a model's weights than fine tuning" is a real result (albeit the opposite of useful), though I would want to do more actual benchmarking before we claim that it's cheaper too confidently. I don't think it's a qualitative improvement over what fine tuning can do, thus hedging and saying tentative

I'm pretty skeptical that this technique is what you end up using if you approach the problem of removing refusal behavior technique-agnostically, e.g. trying to carefully tune your fine-tuning setup, and then pick the best technique.

11Rohin Shah10h
??? Come on, there's clearly a difference between "we can find an Arabic feature when we go looking for anything interpretable" vs "we chose from the relatively small set of practically important things and succeeded in doing something interesting in that domain". I definitely agree this isn't yet close to "doing something useful, beyond what well-tuned baselines can do". But this should presumably rule out some hypotheses that current interpretability results are due to an extreme streetlight effect? (I suppose you could have already been 100% confident that results so far weren't the result of extreme streetlight effect and so you didn't update, but imo that would just make you overconfident in how good current mech interp is.) (I'm basically saying similar things as Lawrence.)
5Buck Shlegeris3h
Oh okay, you're saying the core point is that this project was less streetlighty because the topic you investigated was determined by the field's interest rather than cherrypicking. I actually hadn't understood that this is what you were saying. I agree that this makes the results slightly better.

The 9th AI Safety Camp (AISC9) just ended, and as usual, it was a success! 

Follow this link to find project summaries, links to their outputs, recordings to the end of camp presentations and contact info to all our teams in case you want to engage more.

AISC9 both had the largest number of participants (159) and the smallest number of staff (2) of all the camps we’ve done so far. Me and Remmelt have proven that if necessary, we can do this with just the two of us, and luckily our fundraising campaign raised just enough money to pay me and Remmelt to do one more AISC. After that, the future is more uncertain, but that’s almost always the case for small non profit projects.

 

Get involved in AISC10

AISC10 will follow...

The Löwenheim–Skolem theorem implies, among other things, that any first-order theory whose symbols are countable, and which has an infinite model, has a countably infinite model. This means that, in attempting to refer to uncountably infinite structures (such as in set theory), one "may as well" be referring to an only countably infinite structure, as far as proofs are concerned.

The main limitation I see with this theorem is that it preserves arbitrarily deep quantifier nesting. In Peano arithmetic, it is possible to form statements that correspond (under the standard interpretation) to arbitrary statements in the arithmetic hierarchy (by which I mean, the union of and for arbitrary n). Not all of these statements are computable. In general, the question of whether a given statement is...

1Alex Mennen5d
I see that when I commented yesterday, I was confused about how you had defined U. You're right that you don't need a consistent guessing oracle to get from U to a completion of U, since the axioms are all atomic propositions, and you can just set the remaining atomic propositions however you want. However, this introduces the problem that getting the axioms of U requires a halting oracle, not just a consistent guessing oracle, since to tell whether something is an axiom, you need to know whether there actually is a proof of a given thing in T.
1Jessica Taylor4d
The axioms of U are recursively enumerable. You run all M(i,j) in parallel and output a new axiom whenever one halts. That's enough to computably check a proof if the proof specifies the indices of all axioms used in the recursive enumeration.

Yeah, sorry that was unclear; there's no need for any form of hypercomputation to get an enumeration of the axioms of U. But you need a halting oracle to distinguish between the axioms and non-axioms. If you don't care about distinguishing axioms from non-axioms, but you do want to get an assignment of truthvalues to the atomic formulas Q(i,j) that's consistent with the axioms of U, then that is applying a consistent guessing oracle to U.

1Jessica Taylor5d
Thanks, didn't know about the low basis theorem.

TL;DR: In this post, I distinguish between two related concepts in neural network interpretability: polysemanticity and superposition. Neuron polysemanticity is the observed phenomena that many neurons seem to fire (have large, positive activations) on multiple unrelated concepts. Superposition is a specific explanation for neuron (or attention head) polysemanticity, where a neural network represents more sparse features than there are neurons (or number of/dimension of attention heads) in near-orthogonal directions. I provide three ways neurons/attention heads can be polysemantic without superposition: non-neuron aligned orthogonal features, non-linear feature representations, and compositional representation without features. I conclude by listing a few reasons why it might be important to distinguish the two concepts.

Epistemic status: I wrote this “quickly” in about 12 hours, as otherwise it wouldn’t have come out at all. Think of...

5Lucius Bushnaq2d
Thank you, I've been hoping someone would write this disclaimer post. I'd add on another possible explanation for polysemanticity, which is that the model might be thinking in a limited number of linearly represented concepts, but those concepts need not match onto concepts humans are already familiar with. At least not all of them. Just because the simple meaning of a direction doesn't jump out at an interp researcher when they look at a couple of activating dataset examples doesn't mean it doesn't have one. Humans probably wouldn't even always recognise the concepts other humans think in on sight. Imagine a researcher who hasn't studied thermodynamics much looking at a direction in a model that tracks the estimated entropy of a thermodynamic system it's monitoring: 'It seems to sort of activate more when the system is warmer. But that's not all it's doing. Sometimes it also goes up when two separated pockets of different gases mix together, for example. Must be polysemantic.'

Thanks!

I was grouping that with “the computation may require mixing together ‘natural’ concepts” in my head. After all, entropy isn’t an observable in the environment, it’s something you derive to better model the environment. But I agree that “the concept may not be one you understand” seems more central.

In 2021, I proposed measuring progress in the perplexity of language models and extrapolating past results to determine when language models were expected to reach roughly "human-level" performance. Here, I build on that approach by introducing a more systematic and precise method of forecasting progress in language modeling that employs scaling laws to make predictions.

The full report for this forecasting method can be found in this document. In this blog post I'll try to explain all the essential elements of the approach without providing excessive detail regarding the technical derivations.

This approach can be contrasted with Ajeya Cotra's Bio Anchors model, providing a new method for forecasting the arrival of transformative AI (TAI). I will tentatively call it the "Direct Approach", since it makes use of scaling laws...

I'm confused about how heterogeneity in data quality interacts with scaling. Surely training a LM on scientific papers would give different results from training it on web spam, but data quality is not an input to the scaling law... This makes me wonder whether your proposed forecasting method might have some kind of blind spot in this regard, for example failing to take into account that AI labs have probably already fed all the scientific papers they can into their training processes. If future LMs train on additional data that have little to do with science, could that keep reducing overall cross-entropy loss (as scientific papers become a smaller fraction of the overall corpus) but fail to increase scientific ability?

Over the last couple of years, mechanistic interpretability has seen substantial progress. Part of this progress has been enabled by the identification of superposition as a key barrier to understanding neural networks (Elhage et al., 2022) and the identification of sparse autoencoders as a solution to superposition (Sharkey et al., 2022Cunningham et al., 2023Bricken et al., 2023). 

From our current vantage point, I think there’s a relatively clear roadmap toward a world where mechanistic interpretability is useful for safety. This post outlines my views on what progress in mechanistic interpretability looks like and what I think is achievable by the field in the next 2+ years. It represents a rough outline of what I plan to work on in the near future.

My thinking and work is, of course,...

We propose a simple fix: Use  instead of , which seems to be a Pareto improvement over  (at least in some real models, though results might be mixed) in terms of the number of features required to achieve a given reconstruction error.

When I was discussing better sparsity penalties with Lawrence, and the fact that I observed some instability in in toy models of super-position, he pointed out that the gradient of norm explodes near zero, meaning that features with "small errors" that cause them to h... (read more)

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