Trying to understand John Wentworth's research agenda

Oli, you wanna kick us off?

I mostly plan to observe (and make edits/suggestions) here, but I'll chime in if I think there is something particularly important being missed.

Ok, context for this dialogue is that I was evaluating your LTFF application, and you were like "I would like to do more research on natural abstractions/maybe release products that test my hypotheses, can you give me money?". 

I then figured that given that I've been trying to make dialogues happen on LW, we might also be able to create some positive externalities by making a dialogue about your research, which allows other people who read it later to also get to learn more about what you are working on. 

I've generally liked a lot of your historical contributions to a bunch of AI Alignment stuff, but you haven't actually written much about your current central research agenda/direction, which does feel like a thing I should understand at least in broad terms before finishing my evaluation of your LTFF application.

My current strawman of your natural abstraction research is approximately "John is working on ontology identification/manipulation, just like everyone else these days". By which I mean, it feels like the central theme of Paul's research, a bunch of the most interesting parts of Anthropic's prosaic steering/interpretability work, and some of the more interesting MIRI work. 

Here are some things that I associate with this line of research:

• Trying to understand the mapping between concepts that we have and the concepts that an AI would use in the process of trying to achieve its goals/reason about the world
• Trying to get to a point where if we have an AI system that arrives at some conclusion, that we have some model of "what reasoning did it very roughly use to arrive at that conclusion" 
• A major research problem that keeps coming up in this space is "ontology combination", like if I have one argument that uses an ontology that carves reality at joints X, and another argument that carves reality at joints Y, how do I combine them? This feels like one of the central components of heuristic arguments, and also is one of the key components of cartesian frames.

But I am not super confident that any of this matches that closely to the research you've been doing. I also haven't had a sense that people have been making tons of progress here, and at least in the case of Paul's heuristic arguments work I've mostly been jokingly referring to it as "in order to align an AI I just first have to formalize all of epistemology", and while I think that's a cool goal, it does seem like one that's pretty hard and on priors I don't expect someone to just solve it in the next few years.

Ok, I'm just gonna state our core result from the past few months, then we can unpack how that relates the all the things you're talking about.

Suppose I have two probabilistic models (e.g. from two different agents), which make the same predictions over some "observables" X. For instance, picture two image generators which generate basically the same distribution of images, but using different internal architectures. The two models differ in using different internal concepts - operationalized here as different internal latent variables.

Now, suppose one of the models has some internal latent ${\Lambda }^{\prime }$ which (under that model) mediates between two chunks of observable variables - this would be a pretty typical thing for an internal latent in some generative model. Then we can give some simple sufficient conditions on a latent $\Lambda$ in the other model, such that $\Lambda \to {\Lambda }^{\prime }\to X$.

Another possibility (dual to the previous claim): suppose that one of the two models has some internal latent ${\Lambda }^{\prime }$ which (under that model) can be precisely estimated from any of several different subsets of the observables - i.e. we can drop any one part of the observables and still get a precise estimate of ${\Lambda }^{\prime }$. Then, under the same simple sufficient conditions on $\Lambda$ in the other model, ${\Lambda }^{\prime }\to \Lambda \to X$.

A standard example here is temperature ($\Lambda$) in an ideal gas. It satisfies the sufficient conditions, so I can look at any model which makes the same predictions about the gas, and look at any latent ${\Lambda }^{\prime }$ in that model which mediates between two far-apart chunks of gas, and I'll find that that ${\Lambda }^{\prime }$ includes temperature (i.e. temperature is a function of ${\Lambda }^{\prime }$). Or I can look at any ${\Lambda }^{\prime }$ which can be estimated precisely from any little chunk of the gas, and I'll find that temperature includes ${\Lambda }^{\prime }$ (i.e. ${\Lambda }^{\prime }$ is a function of temperature).

... and crucially, this all plays well with approximation, so if e.g. ${\Lambda }^{\prime }$ approximately mediates between two chunks then we get an approximate claim about the two latents.

So the upshot of all that is: we have a way to look at some properties of latent variables ("concepts") internal to one model, and say how they'll relate to broad classes of latents in another model.

Ok, what does it mean to "mediate between two chunks of observable variables"? 

It's mediation in the sense of conditional independence - so e.g., two chunks of gas which aren't too close together have approximately independent low-level state given their temperature, or two not-too-close-together chunks of an image spit out by an image generator are independent conditional on some "long-range" latents upstream of both of them.

(In particular, this mediation thing is relevant to any mind which is factoring its model of the world in such a way that the two chunks are in different "factors", with some relatively-sparse interaction between them.)

What do the arrows mean in this equation? 

$\Lambda \to {\Lambda }^{\prime }\to X$

The arrow-diagrams are using Bayes net notation, so e.g. $\Lambda \to {\Lambda }^{\prime }\to X$ is saying that $X$ and $\Lambda$ are independent given ${\Lambda }^{\prime }$, or equivalently that $\Lambda$ tells us nothing more about $X$ once we know ${\Lambda }^{\prime }$.

(Also, if you'd prefer a description more zoomed-out than this, we can do that instead.)

Cool, let me think out loud while I am trying to translate this math into more concrete examples for me. 

Here is a random example of two programs that use different ontologies but have the same probability distribution over some set of observables. 

Let's say the programs do addition and one of them uses integers and the other one uses floating point numbers, and I evaluate them both in the range of 1-100 or so, where the floating point error shouldn't matter.

Does the thing you are saying have any relevance to this matter?

Naively I feel like what you are saying translates to something like "if I know the floating point representation of a number, I should be able to find some way of using that representation in the context of the integer program to get the same result". But I sure don't immediately understand how to do that. I mean, I can translate them, of course, but I don't really know what to say beyond that.

Ok, so first we need to find either some internal thing which mediates between two parts of the "observables" (i.e. the numbers passed in and out), or some internal thing which we can precisely estimate from subsets of the observables.

For instance: maybe I look inside the integer-adder, and find that there's a carry (e.g. number "carried from" the 1's-place to the 10's-place), and the carry mediates between the most-significant-digits of the inputs/outputs, and the least-significant-digits.

Then, I know that any quantity which can be computed from either the most-significant-digits or the least-significant digits (i.e. the same quantity must be computable from either one) is a function of that carry. So if the floating-point adder is using anything along those lines, I know it's a function of the carry in the integer-adder's ontology.

(In this particular example I don't think we have any such interesting quantity; our "observables" are "already compressed" in some sense, so there's not much nontrivial to say about the relationship between the two programs.)

Ah, so when you are saying $\Lambda \to {\Lambda }^{\prime }\to X$ you don't mean "we can find a $\Lambda$", you are saying "if there is a $\Lambda$ that meets some conditions then we can make it conditionally independent from the observables using ${\Lambda }^{\prime }$"?

Yes.

Ok, cool, that makes more sense to me. What are the conditions on $\Lambda$ that allow us to do that?

Turns out we've already met them. The two conditions are:

• $\Lambda$ must mediate between some chunks of $X$
• $\Lambda$ must be precisely-estimable from all but one of those chunks, for any chunk excluded (i.e. we can drop any one chunk and still get a precise estimate of $\Lambda$).

So for instance, in an ideal gas, far-apart chunks are approximately independent given the temperature, and we can precisely estimate the temperature from any one (or a few) chunks. So, temperature in that setting satisfies the conditions. And approximation works, so that would also carry over to approximately-ideal gases.

Ok, so what we are saying here is something like "if I have two systems that somehow model the behavior of ideal gases, if there is any latent variable that mediates between distant clusters of gas, then I must be able to extract temperature from that variable"? 

Of course, we have no guarantee that any such system actually has any latent variable that mediates between the predictions about distant clusters of gas. Like, the thing could just be a big pre-computed lookup table.

That's exactly right. We do have some reasons to expect mediation-heavy models to be instrumentally convergent, but that's a separate story.

I find it hard to come up with examples of the "precisely calculable" condition. Like, what are some realistic situations where that is the case?

Sure, the "precisely calculable" is actually IMO easier to see once you know what to look for. Examples:

• We can get a good estimate of the consensus genome of a species by looking at a few members of the species.
• ... for that matter, we can get a good estimate of all sorts of properties of a species by looking at a few members of the species. Body shape, typical developmental trajectory (incl. e.g. weight or size at each age), behaviors, etc
• We can get a good estimate of lots of things about 2009 toyota corollas by looking at a few 2009 toyota corollas.
• In clustering language, we can get a very precise estimate of cluster-statistics (e.g. mean and variance, in a mixture-of-gaussians model) by looking at a moderate-sized sample of points from that cluster.

Notably in these examples, the quantity is not actually "exactly" calculable, but as he's been mentioning we have approximation results which go through fine. (And by "fine," I mean, "with well defined error bounds.")

I do feel a bit confused about how the approximate thing could be true, but let's leave that for later, I can take it as given for now.

So for instance, if (under my model) there's some characteristic properties of 2009 toyota corollas, such that all 2009 toyota corollas are approximately independent given those properties AND I could estimate those properties from a sample of corollas, then I have the conditions.

(Note that I don't actually need to know the values of the properties - e.g. a species' genome can satisfy the properties under my model even if I don't know that species' whole consensus sequence.)

Like, I keep wanting to translate the above into sentences of the form "I believe A because of reason X, you believe A because of reason Y, and we are both correct in our beliefs about A. This means that somehow I can say something about the relation between X and Y", but I feel like I can't yet quite translate things into that form.

Like, I definitely can't make the general case of "therefore X and Y can be calculated from each other", which of course they could not be. So you are saying something weaker. 

Under one model, I can estimate the consensus genomic sequence of oak trees from a small sample of oaks. Under some other medieval model, most oak trees are approximately-independent given some mysterious essence of oak-ness, and that mysterious essence could in-principle be discovered by examining a sample of oak trees, though nobody knows the value of that mysterious essence (they've just hypothesized its existence). Well, good news: the consensus genomic sequence is implicitly included in the mysterious essence of oak-ness.

More precisely: any way of building a joint model which includes both the consensus sequence and the mysterious essence of oak-ness, both with their original relationships to all the "observable" oaks, will say that the consensus genomic sequence is a function of the mysterious essence, i.e. the oaks themselves can tell us nothing additional about the consensus sequence once we know the value of the mysterious essence.

Ok, maybe I am being dumb, but like, let's say you carved your social security number into two oak trees. Now the consensus genomic sequence with your social security number appended can be estimated from any sample of oaks that leaves at most one out. Under some other medieval model there is some mysterious essence of oak-ness that can be discovered via sampling some oak trees. Now, it's definitely not the case that the consensus genomic sequence plus your social security number is implicitly included in the mysterious essence of oak-ness.

Yeah, that's a great example. In this case, the social security number would be excluded from the mysterious essence by having an "estimate from subset" requirement which allows throwing out more than just one oak (and indeed it is pretty typical that we want a stronger requirement along those lines).

However, the flip side is arguably more interesting: if you carve your social security number into enough oak trees, over all the oak trees to ever exist, then your social security number will naturally be part of the "cluster of oak trees". People can change which "concepts" are natural, by changing the environment.

I think this would benefit from more concreteness. John, can you specify your SSN for us?

Ok, so this must be related to the "approximate" stuff I don't understand. Like, if I had to translate the above into the more formal criterion, you would say it fails because like, the oak trees are not actually independent without knowledge of your social security number, but I am kind of failing to make the example work out here. 

I don't think the current example is about "approximation" in the sense we were using it earlier. There's a different notion of "approximation" which is more relevant here: we can totally weaken the conditions to "most chunks of observables are independent given latent", and then the same conclusions still hold. (The reason is that, if most chunks of observables are independent given latent, then we can still find some chunks which are independent given the latent, and then we just use those chunks as the foundation for the claim.)

(More generally, the sort of way we imagine using this machinery is to go looking around in models for chunks of observables over which we can find latents satisfying the conditions; we don't need to use all the observables all the time.)

Ok, I would actually be interested in a rough proof outline here, but probably we should spend some more time talking about higher-level stuff.

Sure, what sorts of higher-level questions do you have?

Like, if you had to give a very short and highly-compressed summary of how this kind of research helps with AI not killing everyone, what would it be? I could also make a first guess and then you can correct me.

My own very short story is something like: 

Well, it really matters to understand the conditions under which AI will develop the same abstractions as humans do, since when they do, if we can also identify and manipulate those abstractions, we can use those to steer powerful AI systems away from having catastrophic consequences.

Sure. Simple story is:

• This gives us some foundations to expect that certain kinds of latents/internal structures will map well across minds/ontologies.
• We can go look for such structures in e.g. nets, see how well they seem to match our own concepts, and have some reason to expect they'll match our own concepts robustly in certain cases.
• Furthermore, as new and more powerful AI comes along, we expect to be able to transport those concepts to the ontologies of those more powerful AIs (insofar as the more powerful AIs still have latents satisfying one or both conditions, which is itself something checkable in-principle).
• ... and insofar as all that works, we can use these sorts of latents as "ontology-transportable" building blocks with which to build more complex concepts.

So, if we can build whatever-kind-of-alignment-machinery we want out of these sorts of building blocks, then we have some reason to expect that machinery to transport well across ontologies, especially to new more-powerful future AI.

To clarify that last part, is your story here something like "we get some low-powered AI systems to do things for reasons we roughly understand and like. Then we make it so that a high-powered AI system does things for roughly the same reasons. That means the high-powered AI system roughly behaves predictably and in a way we like"?

Not the typical thing I'd picture, but sure, that's an example use-case.

My prototypical picture would be more "we decode (a bunch of) the AI's internal language, to the point where we can state something we want in that language, then target its internal search process at that". And the ontology transport matters for both the "decode its internal language" step, and the unstated "transport that same goal to a successor AI" step.

Ah, OK. The "retarget its internal search process at that" part does sound like more the kind of thing you would say.

Ok, so, why are you thinking about maybe building products instead of (e.g.) writing up some of the proofs or results you have so far? I mean, seems fine to validate hypotheses however one likes, but building a product takes a long time, and I don't fully understand the path from that to good things happening (like, to what degree is the path "John has better models of the problem domain vs. John has a pretty concrete and visceral demonstration of a bunch of solutions which then other people adopt and iterate on and then scale?"

So, I've done a lot of "writing up stuff" over the past few years, and the number of people who have usefully built on my technical work has been close to zero. (Though admittedly the latest results are nicer, I do think people would be more likely to build on them, but I don't know how much more.) On the flip side, fork hazards: I have to worry that this stuff is dangerous to share in exactly the worlds where it's most useful.

My hope is that products will give a more useful feedback signal than other peoples' commentary on our technical work.

(Also, we're not planning to make super-polished products, so hopefully the time sink isn't too crazy. Like, we've got some theory here which is pretty novel and cool, if we're doing our jobs well then even kinda-hacky products should be able to do things which nobody else can do today.)

My sense is the usual purpose of publishing proofs and explanations is more than just field-building. My guess is it's also a pretty reasonable part of making your own epistemic state more robust, though that's not like a knock-down argument (and I am not saying people can't come to justifiedly true beliefs without publishing, though I do think justified true belief in the absence of public argument is relatively rare for stuff in this space). 

(Also, we're not planning to make super-polished products, so hopefully the time sink isn't too crazy. Like, we've got some theory here which is pretty novel and cool, if we're doing our jobs well then even kinda-hacky products should be able to do things which nobody else can do today.)

Ok, are we thinking about "products" a bit more in the sense of "Chris Olah's team kind of makes a product with each big release, in the form of like a webapp that allows you to see things and do things with neural networks that weren't possible before" or more in the sense of "you will now actually make a bunch of money and get into YC or whatever"?

My sense is the usual purpose of publishing proofs and explanations is more than just field-building. My guess is it's also a pretty reasonable part of making your own epistemic state more robust...

I agree with that in principle. In practice, the number of people who have usefully identified technical problems in my work is... less than half a dozen. There's also some value in writing it up at all - I have frequently found problems when I go to write things up - but that seems easier to substitute for.

I agree with that in principle. In practice, the number of people who have usefully identified technical problems in my work is... less than half a dozen. 

I mean, six people seems kind of decent. I don't know whether more engagement than that was necessary for e.g. the development of most of quantum mechanics or relativity or electrodynamics.

Ok, are we thinking about "products" a bit more in the sense of "Chris Olah's team kind of makes a product with each big release, in the form of like a webapp that allows you to see things and do things with neural networks that weren't possible before" or more in the sense of "you will now actually make a bunch of money and get into YC or whatever"

Somewhere between those two. Like, making money is a super-useful feedback signal, but we're not looking to go do YC or refocus our whole lives on building a company.

Ok, cool, that helps me get some flavor here.

I have lots more questions to ask, but we are at a natural stopping point. I'll maybe ask some more questions async or post-publishing, but thank you, this was quite helpful!