Richard Ngo
๐ค SpeakerAppearances Over Time
Podcast Appearances
On Goal Models By Richard Ngo Published on February 2, 2026 I'd like to reframe our understanding of the goals of intelligent agents to be in terms of goal models rather than utility functions.
By a goal model I mean the same type of thing as a world model, only representing how you want the world to be, not how you think the world is.
However, note that this still a fairly inchoate idea, since I don't actually know what a world model is.
The concept of goal models is broadly inspired by predictive processing, which treats both beliefs and goals as generative models, the former primarily predicting observations, the latter primarily predicting actions.
This is a very useful idea, which for example allows us to talk about the distance between a belief and a goal, and the process of moving towards a goal, neither of which makes sense from a reward-utility-function perspective.
However, I'm dissatisfied by the idea of defining a world model as a generative model over observations.
It feels analogous to defining a parliament as a generative model over laws.
Yes, technically we can think of parliaments as stochastically outputting laws, but actually the interesting part is in how they do so.
In the case of parliaments, you have a process of internal disagreement and bargaining, which then leads to some compromise output.
In the case of world models, we can perhaps think of them as made up of many smaller, partial, generative models, which sometimes agree and sometimes disagree.
The real question is in how they reach enough of a consensus to produce a single output prediction.
One potential model of that consensus formation process comes from the probabilistic dependency graph formalism, which is a version of Bayesian networks in which different nodes are allowed to disagree with each other.
The most principled way to convert a PDG into a single distribution is to find the distribution which minimizes the inconsistency between all of its nodes.
PDGs seem promising in some ways, but I feel suspicious of any global symmetric of inconsistency.
Instead I'm interested in scale-free approaches under which inconsistencies mostly get resolved locally, though it's worth noting that Oliver's proposed practical algorithm for inconsistency minimization is a local one.
It's also possible that the predictive processing to active inference people have a better model of this process which I don't know about, since I haven't made it very deep into that literature yet.
Anyway, suppose we're thinking of goal models as generative models of observations for now.
What does this buy us over understanding goals in terms of utility functions?
The key trade-off is that utility functions are global but shallow whereas goal models are local but deep.
That is, we typically think of a utility function as something that takes as input any state or alternatively any trajectory of the world and spits out a real number.