> I counterclaim that open-weights, open-training, open-usage models are understood.
Knowing what is in the model is a long way from understanding it.
The entire field of mechanistic interpretability exists to try to understand models. Read for example "Open Problems in Mechanistic Interpretability"[1]. To quote:
> Developers only need to design the training process; they do not need to – and in almost all cases, do not – understand the neural mechanisms underlying the capabilities learned by an AI system.[1]
(emphasis mine)
Here's a practical example relevant to this case: Is it possible to monitor a LLM (the LLM activations themselves, not the actions) for cases where the actions it is about to perform (eg upload files to a PLA website) are not reflected in the goals of the prompt and are not visible in the thinking trace?
At the moment that isn't possible. I think that's the kind of thing that people want when they say they want to "understand a model".
> Knowing what is in the model is a long way from understanding it.
The claim I was arguing against reads as follows:
> You don't know what is in any model, open source, closed source, from China or from the US.
I contend that you do, in fact, know what's in a fully open model. I don't really get why the goalposts need to move beyond that to something I wasn't saying about bounding the potential outputs given unbounded inputs and nondeterministic choice of inference parameters.
I'm literally saying that if you see what goes into the sausage it's foolishness to argue you can't know what's in the sausage.
Knowing what is in the model is a long way from understanding it.
The entire field of mechanistic interpretability exists to try to understand models. Read for example "Open Problems in Mechanistic Interpretability"[1]. To quote:
> Developers only need to design the training process; they do not need to – and in almost all cases, do not – understand the neural mechanisms underlying the capabilities learned by an AI system.[1]
(emphasis mine)
Here's a practical example relevant to this case: Is it possible to monitor a LLM (the LLM activations themselves, not the actions) for cases where the actions it is about to perform (eg upload files to a PLA website) are not reflected in the goals of the prompt and are not visible in the thinking trace?
At the moment that isn't possible. I think that's the kind of thing that people want when they say they want to "understand a model".
[1] https://arxiv.org/pdf/2501.16496