from Hacker News

Yann LeCun, Pioneer of AI, Thinks Today's LLM's Are Nearly Obsolete

by alphadelphi on 4/2/25, 10:59 PM with 140 comments

  • by antirez on 4/5/25, 4:31 PM

    As LLMs do things thought to be impossible before, LeCun adjusts his statements about LLMs, but at the same time his credibility goes lower and lower. He started saying that LLMs were just predicting words using a probabilistic model, like a better Markov Chain, basically. It was already pretty clear that this was not the case as even GPT3 could do summarization well enough, and there is no probabilistic link between the words of a text and the gist of the content, still he was saying that at the time of GPT3.5 I believe. Then he adjusted this vision when talking with Hinton publicly, saying "I don't deny there is more than just probabilistic thing...". He started saying: not longer just simply probabilistic but they can only regurgitate things they saw in the training set, often explicitly telling people that novel questions could NEVER solved by LLMs, with examples of prompts failing at the time he was saying that and so forth. Now reasoning models can solve problems they never saw, and o3 did huge progresses on ARC, so he adjusted again: for AGI we will need more. And so forth.

    So at this point it does not matter what you believe about LLMs: in general, to trust LeCun words is not a good idea. Add to this that LeCun is directing an AI lab that as the same point has the following huge issues:

    1. Weakest ever LLM among the big labs with similar resources (and smaller resources: DeepSeek).

    2. They say they are focusing on open source models, but the license is among the less open than the available open weight models.

    3. LLMs and in general all the new AI wave puts CNNs, a field where LeCun worked (but that didn't started himself) a lot more in perspective, and now it's just a chapter in a book that is composed mostly of other techniques.

    Btw, other researchers that were in the LeCun side, changed side recently, saying that now "is different" because of CoT, that is the symbolic reasoning they were blabling before. But CoT is stil regressive next token without any architectural change, so, no, they were wrong, too.

  • by gsf_emergency_2 on 4/5/25, 3:45 PM

    Recent talk: https://www.youtube.com/watch?v=ETZfkkv6V7Y

    LeCun, "Mathematical Obstacles on the Way to Human-Level AI"

    Slide (Why autoregressive models suck)

    https://xcancel.com/ravi_mohan/status/1906612309880930641

  • by djoldman on 4/5/25, 4:58 PM

    The idolatry and drama surrounding LeCun, Hinton, Schmidhuber, etc. is likely a distraction. This includes their various predictions.

    More interesting is their research work. JEPA is what LeCun is betting on:

    https://ai.meta.com/blog/v-jepa-yann-lecun-ai-model-video-jo...

  • by redox99 on 4/5/25, 5:41 PM

    LeCun has been very salty of LLMs ever since ChatGPT came out.
  • by csdvrx on 4/5/25, 3:57 PM

    > Returning to the topic of the limitations of LLMs, LeCun explains, "An LLM produces one token after another. It goes through a fixed amount of computation to produce a token, and that's clearly System 1—it's reactive, right? There's no reasoning," a reference to Daniel Kahneman's influential framework that distinguishes between the human brain's fast, intuitive method of thinking (System 1) and the method of slower, more deliberative reasoning (System 2).

    Many people believe that "wants" come first, and are then followed by rationalizations. It's also a theory that's supported by medical imaging.

    Maybe the LLM are a good emulation of system-2 (their perfomance sugggest it is), and what's missing is system-1, the "reptilian" brain, based on emotions like love, fear, aggression, (etc.).

    For all we know, the system-1 could use the same embeddings, and just work in parallel and produce tokens that are used to guide the system-2.

    Personally, I trust my "emotions" and "gut feelings": I believe they are things "not yet rationalized" by my system-2, coming straight from my system-1.

    I know it's very unpopular among nerds, but it has worked well enough for me!

  • by bitethecutebait on 4/5/25, 9:23 PM

    there's a bunch of stuff imperative to his thriving that has become obsolete to others 15 years ago ... maybe it's time for a few 'sabbatical' years ...
  • by ejang0 on 4/5/25, 3:42 PM

    "[Yann LeCun] believes [current] LLMs will be largely obsolete within five years."
  • by GMoromisato on 4/5/25, 4:22 PM

    I remember reading Douglas Hofstadter's Fluid Concepts and Creative Analogies [https://en.wikipedia.org/wiki/Fluid_Concepts_and_Creative_An...]

    He wrote about Copycat, a program for understanding analogies ("abc is to 123 as cba is to ???"). The program worked at the symbolic level, in the sense that it hard-coded a network of relationships between words and characters. I wonder how close he was to "inventing" an LLM? The insight he needed was that instead of hard-coding patterns, he should have just trained on a vast set of patterns.

    Hofstadter focused on Copycat because he saw pattern-matching as the core ability of intelligence. Unlocking that, in his view, would unlock AI. And, of course, pattern-matching is exactly what LLMs are good for.

    I think he's right. Intelligence isn't about logic. In the early days of AI, people thought that a chess-playing computer would necessarily be intelligent, but that was clearly a dead-end. Logic is not the hard part. The hard part is pattern-matching.

    In fact, pattern-matching is all there is: That's a bear, run away; I'm in a restaurant, I need to order; this is like a binary tree, I can solve it recursively.

    I honestly can't come up with a situation that calls for intelligence that can't be solved by pattern-matching.

    In my opinion, LeCun is moving the goal-posts. He's saying LLMs make mistakes and therefore they aren't intelligent and aren't useful. Obviously that's wrong: humans make mistakes and are usually considered both intelligent and useful.

    I wonder if there is a necessary relationship between intelligence and mistakes. If you can solve a problem algorithmically (e.g., long-division) then there won't be mistakes, but you don't need intelligence (you just follow the algorithm). But if you need intelligence (because no algorithm exists) then there will always be mistakes.

  • by grandempire on 4/5/25, 4:50 PM

    Is this the guy who tweets all day and gets in online fights?
  • by asdev on 4/5/25, 4:29 PM

    outside of text generation and search, LLMs have not delivered any significant value