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Comment by davesque

2 years ago

A big red flag for me was that Sundar was prompting the model to report lots of facts that can be either true or false. We all saw the benchmark figures that they published and the results mostly showed marginal improvements. In other words, the issue of hallucination has not been solved. But the demo seemed to imply that it had. My conclusion was that they had mostly cherry picked instances in which the model happened to report correct or consistent information.

They oversold its capabilities, but it does still seem that multi-modal models are going to be a requirement for AI to converge on a consistent idea of what kinds of phenomena are truly likely to be observed across modalities. So it's a good step forward. Now if they can just show us convincingly that a given architecture is actually modeling causality.

i think this was demonstrated in that mark rober promo video[1] where he asked why the paper airplane stalled by blatantly leading the witness.

"do you believe that a pocket of hot air would lead to lower air pressure causing my plane to stall?"

he could barely even phrase the question correctly because it was so awkward. just embarrassing.

[1] https://www.youtube.com/watch?v=mHZSrtl4zX0&t=277s

  • Yeah, this was so obvious too. Clearly Mark Rober tried to ask it what to try and got stupid answers, then tried to give it clues and had to get really specific before he got a usable answer.

The issue of hallucinations won't be solved with the RAG approach. It requires a fundamentally different architecture. These aren't my words but Yann LeCun's. You could easily understand if you spend some time playing around. The autoregressive nature won't allow the LLMs to create an internally consistent model before answering the question. We have approaches like Chain of Thought and others, but they are merely band-aids and superficially address the issue.

  • If you build a complex Chain if Thought style Agent and then train/finetune further by reinforcement learning with this architecture then it is not a band-aid anymore, it is an integral part of the model and the weights will optimize to make use of this CoT ability.

    • It's been 3.5 years since GPT-3 was released, and just over a year since ChatGPT was released to the public.

      If it was possible to solve LLM hallucinations with simple Chain-of-Thought style agents, someone would have done that and released a product by now.

      The fact that nobody has released such a product, is pretty strong evidence that you can't fix hallucinations via Chain-of-Thought or Retrieval-Augmented Generation, or any other band-aid approaches.

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Ever since the "stochastic parrots" and "super-autocomplete" criticisms of LLMs, the question is whether hallucinations are solvable in principle at all. And if hallucinations are solvable, it would of such basic and fundamental scientific importance that I think would be another mini-breakthrough in AI.

  • An interesting perspective on this I’ve heard discussed is whether hallucinations ought to be solved at all, or whether they are core to the way human intelligence works as well, in the sense that that is what is needed to produce narratives.

    I believe it is Hinton that prefers “confabulation” to “hallucination” because it’s more accurate. The example in the discussion about hallucination/confabulation was that of someone who had been present in the room during Nixon’s Watergate conversations. Interviewed about what he heard, he provided a narrative that got many facts wrong (who said what, and what exactly was said). Later, when audio tapes surfaced, the inaccuracies in his testimony became known. However, he had “confabulated truthfully”. That is, he had made up a narrative that fit his recall as best as he was able, and the gist of it was true.

    Without the ability to confabulate, he would have been unable to tell his story.

    (Incidentally, because I did not check the facts of what I just recounted, I just did the same thing…)

    • > Without the ability to confabulate, he would have been unable to tell his story.

      You can tell a story without making up fiction. Just say you don’t know when you don’t know.

      Inaccurate information is worse than no information.

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    • I've read similar thoughts before about AI art. When the process was still developing, you would see AI "artwork" that was the most inhumanly uncanny pictures. Things that twisted the physical forms that human artists perceive with the fundamental pixel format/denoising algorithms that the AI works with. It was just uniquely AI and not something a human being would be able to replicate. "There are no errors just happy accidents." In there you say there was a real art medium/genre with its own intrinsic worth.

      After a few months AI developers refined the process to just replicate images so they looked like a human being made them, in effect killing what was the real AI art.

These LLMs do not have a concept of factual correctness and are not trained/optimized as such. I find it laughable that people expect these things to act like quiz bots - this misunderstands the nature of a generative LLM entirely.

It simply spits out whatever output sequence it feels is most likely to occur after your input sequence. How it defines “most likely” is the subject of much research, but to optimize for factual correctness is a completely different endeavor. In certain cases (like coding problems) it can sound smart enough because for certain prompts, the approximate consensus of all available text on the internet is pretty much true and is unpolluted by garbage content from laypeople. It is also good at generating generic fluffy “content” although the value of this feature escapes me.

In the end the quality of the information it will get back to you is no better than the quality of a thorough google search.. it will just get you a more concise and well-formatted answer faster.

  • > because for certain prompts, the approximate consensus of all available text on the internet is pretty much true

    I think you're slightly mischaracterising things here. It has potential to be at least slightly and possibly much better than that. This is evidenced by the fact it is much better than chance at answering "novel" questions that don't have a direct source in the training data. Why it can do it is because at a certain point, to solve the optimisation problem of "what word comes next" the least complex strategy actually becomes to start modeling principles of logic and facts connecting them. It is not in any systematic or reliable way so you can't ever guarantee when or how well it is going to apply these, but it is absolutely learning higher order patterns than simple text / pattern matching, and it is absolutely able to generalise these across topics.

    • You’re absolutely right and I’m sure that something resembling higher-level pattern matching is present in the architecture and weights of the model, I’m just saying that I’m not aware of “logical thought” being explicitly optimized or designed for - it’s more of a sometimes-emergent feature of a machine that tries to approximate the content of the internet, which for some topics is dominated by mostly logical thought. I’m also unaware of a ground truth against which “correct facts” could even be trained for..

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  • The first question I always ask myself in such cases: how much input data has a simple "I don't know" lines? This is clearly a concept (not knowing sth) that has to be learned in order to be expressed in the output.

    • What stops you from asking the same question multiple times, and seeing if the answers are consistent. I am sure the capital of France is always going to come out Paris, but the name of a river passing a small village might be hallucinated differently. Even better - use two different models, if they agree it's probably true. And probably the best - provide the data to the model in context, if you have a good source. Don't use the model as fact knowledge base, use RAG.

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    • Ha, probably an insignificant amount. The internet is nothing if not confidently-stated positive results, no matter how wrong they might be. No wonder this is how LLMs act.

  • > In the end the quality of the information it will get back to you is no better than the quality of a thorough google search.. it will just get you a more concise and well-formatted answer faster.

    I would say it’s worse than Google search. Google tells you when it can’t find what you are looking for. LLMs “guess” a bullshit answer.

  • > It simply spits out whatever output sequence it feels is most likely to occur after your input sequence... but to optimize for factual correctness is a completely different endeavor

    What if the input sequence says "the following is truth:", assuming it skillfully predicts following text, it would mean telling the most likely truth according to its training data.