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Why I'm still bearish on LLMs after Navier-Stokes

496 points · 653 comments · jaykru

  1. carodgers · · focus · HN ↗
    This April 2026 paper is a fun and related read.

    <a href="https:&#x2F;&#x2F;arxiv.org&#x2F;html&#x2F;2509.24239v4" rel="nofollow">https:&#x2F;&#x2F;arxiv.org&#x2F;html&#x2F;2509.24239v4

    Researchers asked frontier models to play chess. Have a look at the MAR rates in Table 3. When not explicitly told which moves were legal, no model identified legal moves at a rate better than 80%. Many asked for more illegal moves than legal moves. And even when explicitly told which moves were legal, the models continued to ask for illegal moves. With illegal asks discarded, none of the bots could beat a chess model calibrated to 1100 ELO.

    The author of the originating post says that &quot;current frontier models need laborious oversight and guardrails on even the simplest tasks&quot;, and he&#x27;s absolutely correct.

    1. famouswaffles · · focus · HN ↗
      Frontier labs don&#x27;t care about chess. If OpenAI cared, GPT-7 could be a grandmaster+ level chess player. In fact there&#x27;s a google paper on grandmaster level chess without search with a 270M transformer. Outside that, there was gpt-3.5-turbo instruct which was incidentally a 1800 lichess elo player that didn&#x27;t make any illegal moves even after a few thousand moves. Frontier labs care deeply about automating knowledge work and computer use. They are working hard on getting models better and better, and they are succeeding. Astra is a step change on that front. So good luck i guess, if chess performance is your barometer.
      1. bigstrat2003 · · focus · HN ↗
        &gt; Frontier labs don&#x27;t care about chess. If OpenAI cared, GPT-7 could be a grandmaster+ level chess player.

        If the models were actually intelligent, the way that the boosters claim, they wouldn&#x27;t need to be tuned to play chess in order to be good at it. That&#x27;s kind of the point of intelligence, that it is generically applicable to whichever task one wishes.

        1. Gregkion · · focus · HN ↗
          Thats just absolutly not true.

          A human being has general intelligence and needs A LOT of training and finetuning to become good in chess.

          And there is a relevant and significant difference between the expectation of an AGI and an ASI system.

          1. foldr · · focus · HN ↗
            Humans don&#x27;t need a lot of training and finite tuning to make only legal moves.

            An intelligent adult could simply read a short summary of the rules of chess and then, if they were careful, play a very bad game of chess without making illegal moves.

            An LLM that has not been trained on any chess data cannot do that, at present. If you doubt it, take a current model and tell it that you want to play it at a variant of chess where, say, knights can also move diagonally like bishops. A human can easily adapt to this new ruleset (even if they make tactical mistakes, not having practiced with this variant of the rules).

            1. thom · · focus · HN ↗
              How long a prompt do you think would be required to cajole an LLM into making legal moves at the rate of a human? Or do you think no amount of prompting could do that?
              1. foldr · · focus · HN ↗
                I don&#x27;t know. My understanding is that current models will eventually fall into making illegal moves in longer chess games, and that no amount of prompting reliably gets them to stop doing so.
                1. zahlman · · focus · HN ↗
                  More importantly, beginner human players don&#x27;t exhibit that tendency. The history of the position doesn&#x27;t bother a human (except as required for castling and en passant rules), and the analysis becomes generally easier as pieces come off the board.
                  1. thom · · focus · HN ↗
                    Humans do make these errors when playing blindfolded. If you even the playing field and give the LLM the position at each turn, it does not make mistakes.
                    1. zahlman · · focus · HN ↗
                      &gt; If you even the playing field and give the LLM the position at each turn, it does not make mistakes.

                      It absolutely still makes mistakes if you ask it to draw the board each turn, which should be equivalent to giving it the position because it only has to update one move at a time and then it has the position in the context window.

                      1. thom · · focus · HN ↗
                        Yes, we can come up with all sorts of weird situations where you can get it to be confused. But what I&#x27;m saying is it&#x27;s _trivial_ to give it a simple prompt that prevents it from ever making any errors, and so I don&#x27;t think it&#x27;s this big LLM gotcha (of which there are many!)
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