Hacker News new | ask | show | jobs
by throw5 74 days ago
> Just by a thing being common in training data doesn't mean it will be produced.

That's not what I said at all. I never said it will be produced. I said there is some probability of it being produced.

> False, it goes against the RL/HF and other post training goals.

It is correct that frequency in training data alone does not determine outputs, and that post-training (RLHF, policies, etc.) is meant to steer the model away from undesirable behavior.

But those mechanisms do not make such outputs impossible. They just make them less likely. The underlying system is still probabilistic and operating with incomplete context.

I am not sure how you can be so confident that a probabilistic model would never produce `git reset --hard`. There is nothing inherent in how LLMs work that makes that sequence impossible to generate.

1 comments

It is meaningless to say that because the author was able to reproduce it multiple times.
> It is meaningless to say that because the author was able to reproduce it multiple times.

I don't know how that refutes what I'm saying.

The behaviour was reproduced multiple times, so it is clearly an observable outcome, not a one-off. It just shows that the probability of `git reset --hard` is > 0 even with RLHF and post-training.

If it reliably reproduces something undesirable with statistical significance, then it is a bug. It can be fixed with RLHF.
Yes, if something is reproducible and undesirable, it is a bug and RLHF can reduce it. I'm not disupting that. "reduce" is the keyword here. You can't eliminate them entirely.

My point is that fixing one bug does not eliminate the class of bugs. Heck, it does not even fix that one bug deterministically. You only reduce its probability like you rightly said.

With git commands, there is not like a system like Lean that can formally reject invalid proofs. Really I think the mathematicians have got it easier with LLMs because a proof is either valid or invalid. It's not so clear cut with git commands. Almost any command can be valid in some narrow context, which makes it much harder to reject undesirable outputs entirely.

Until the underlying probabilities of undesirable output become negligible so much that they become practically impossible, these kinds of issues will keep surfacing even if you address individual bugs. Will the probabilities become so low someday that these issues are practically impossible? Maybe. But we are not there yet. Until then, we should recalibrate our expectations and rely on deterministic safeguards outside the LLM.

When sampling from an LLM people normally truncate the token probability distribution so that low-probability tokens are never sampled. So the model shouldn't produce really weird outputs even if they technically have nonzero probability in the pre/post training data.