May 18, 2025
world models
The Case for Language-Native World Models
This post is about a framework I’ve been working on that I call “language-native world modeling.” The key idea is to separate language from planning and simulation. Language isn’t the substrate of thought, it’s the interface. What we really want to build is a system that interprets language into structured latent representations of the world, simulates how that world might evolve, and then uses language only when it needs to communicate something back to us.
It starts with a simple observation: humans reasoned before we spoke. Long before syntax or grammar emerged, our brains were already simulating spatial layouts, predicting actions, modeling goals. Language didn’t give us reasoning. It did, however, give us a powerful way to interface with it. Language supercharged cognition by giving us tools to name abstractions, compare counterfactuals, and share mental simulations. But the underlying substrate of world modeling was already there.
That’s what I think we’re missing in LLMs. We treat them like they're intelligent because they complete text well. But completing text is just a visible trace of reasoning. It’s bulky. If you try to represent world states through strings alone, you end up needing five sentences to describe something that could be a clean latent vector — a robot in a kitchen, a cup on the floor, a goal to move it. It’s like trying to draw a diagram using only adjectives. The result is cluttered, slow, and semantically brittle.
That said, there’s growing evidence that language models do form internal representations of the world. Even when trained only on text, they appear to acquire structured latent knowledge about space, causality, physical interactions, and goals. These internal world models seem to support surprisingly coherent behavior, but they’re buried inside the model, inaccessible except through clever prompting or behavioral probing.
The core problem with LLM-based approaches to reasoning is this: we don’t have direct control over those world models. We can only interact with them through the lens of text generation. There’s no clean mechanism to extract, simulate, or manipulate the underlying structure, no way to treat the world model as an explicit, evolving state.
So here’s what I propose. We build a system with three modules:
- A semantic encoder that takes natural language and turns it into a structured latent state. This state is a vector, but not a black-box embedding. It’s structured, as in each dimension corresponds to something interpretable, like object properties or agent location. Optionally, we can use an encoder to project this to a learned latent space to make better embeddings for world prediction, almost like a word embedding model, but used instead to embed world states.
- A latent dynamics model that predicts how this world evolves over time under hypothetical actions. No tokens involved. Just autoregressive simulation in meaning space.
- A verifier that checks whether the final state matches the desired goal, also given in natural language, but embedded into the same latent space as the world state.
- First, it lets us reason over meaning instead of syntax. The system doesn’t get distracted by phrasing. It thinks in structure.
- Second, it allows us to separate grounding from generation. We can evaluate, plan, and simulate in latent space, and only decode to language when needed.
- Third, it reframes intelligence as predictive compression over world-state entropy, not token entropy. That gives us a better measure of understanding.
- Fourth, and maybe most importantly: it gives us explicit control over the world model. Not just prompt-hacking. Not just steering with soft constraints. But actual simulation over latent variables we define and interpret.