I’ve been contemplating this situation. I think that what the author wants out of a Jev-like model is not at all what I want out of it.

> I decided to check this on questions where the answer is well understood. For example:

> A classical particle of mass m is embedded in a system at thermodynamic equilibrium with temperature T. What is its velocity v?

If I feed that into a model, the answer I want is: “the combination of the model and the provided state has nothing useful to add to your prior”.

If I want to know the Maxwell-Boltzmann distribution, I can look it up or I can derive it or I can ask a fancy LLM to do it for me (at the cost of some reasoning tokens and some time - unless I’m using an ultraspeed inference system, I’m not getting this answer in 50ms). [0]

Similarly, if I want to know that 73% of incoming customer support requests are spam/fraud, I should measure that - it’s a property of my system, it takes some manual classification and a database query, and it will be a different percentage than your customer support system would see. I neither expect nor want my classifier to know this (unless I’m using a conventional classifier manually trained on my data, and the whole point of Jev is to avoid this).

What I want out of a system like Jev is to tell me how the probabilities change as a result of the per-sample data I provide. Which, is the case of this Boltzmann distribution question, is nothing: I provided no data and the classifier can infer nothing.

[0] A really good answer would observe that the answer depends on the dimension of the system (probably 3, but 2D systems are a thing) and also on whether the particles are hot enough for relativistic effects to matter (probably not). And maybe a good answer would check whether the material is a gas - the answer for a solid is not the same, but I suppose that’s not classical. Oh, and one shouldn’t forget drift: if you have a classical particle in a moving fluid or a classical charged particle in an electric field, you will again get a different answer.

Yes, I’m being pedantic. But if you want good answers you should be pedantic, and the Jev-like model is not where the pedantry should go.

> So Jev does actually know which distributions are correct, it just fails to produce them

Claims like this needs to be deeply analyized. Models do have some emergent capabilities[1], and I think there's a lot of evidence to show that semantics is actually learned (Word2Vec), and some math seems like it also might be learned (e.g. modular arithmetic). But it's hard to exactly say where there's some internal mechanism generating a true answer and where we're just getting lucky with some distribution so the answer just seems right.

[1] https://arxiv.org/pdf/2502.00873

IMO by asking Jev underspecified questions like this, you're essentially using it as a random number generator (similar to the dice example). On actual NLP problems (including ones with uncertainty under human review) it does appear to be well calibrated: https://leonardgrazian.com/blog/jev-calibration/

this is related to, but not the same as, the question i had in the original thread: https://news.ycombinator.com/item?id=49719097

Also, it's a very small and dumb model. That's the only reason why it's so fast.

not very

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