Unsupervised Learning · 2 min instead of 1 h 22 m · May 15, 2026
LLMs excel only where language is the substrate of reasoning
Former Chief AI Scientist, Meta
Jacob EffronHost · Partner, Redpoint
Growth investor in Abridge, Ramp and Physical Intelligence; ex-Flatiron Health.
About this segment
LeCun says LLMs succeed in math and code because language is the substrate of reasoning there. They are problem solvers, not software architects or creative mathematicians, so humans move up a level of abstraction.
From “Yann LeCun on What Comes After LLMs”, May 15, 2026. Watch the full episode
“LLMs are good programmers they're not software architects they're not computer scientists right but they can program for us”
Yann LeCunat 37:26 · Unsupervised Learning37:26Takeaways
- Math and code are domains where language is the reasoning substrate
- LLMs solve problems but do not create new concepts
- Humans shift to deciding what to build, not how
In this episode
Full episode- 9:04A world model predicts consequences, which LLMs cannot do3:12
- 28:27Tapestry would train an open sovereign model without sharing data7:33
36:33LLMs excel only where language is the substrate of reasoning1:51
Transcript
Transcribed by machine (Whisper) from the episode’s audio, so a word may be off here and there.
- 36:36
keeps going up. Okay, that's very interesting. Now think about those two domains, mathematics and code. Those are two domains where the language itself is the substrate of reasoning. It's not the only substrate of reasoning, but a lot of, when you do mathematics, the formal way on a piece of paper, not the intuitive stuff, But you manipulate language, right? And LLMs are really good at this. So, you know, proving theorems and stuff like that, that's what LLMs are really good at.
- 37:08
They're not so good at the sort of, you know, coming up with good concepts and definitions and things like that. It's more like here is a problem, solve it. They're problem solvers. Mathematics is not just problem solving, right? Most of it is actually a creative act that those things don't do. and same for code so LLMs are good programmers they're not software architects they're not computer scientists right but they can program for us so they're not in a state where they can just you know replace humans entirely it changes the world of humans so humans now you know kind of go one level up in the abstraction hierarchy and our role is to decide way to build but like building it you know you can you can get help from llms but okay that's the the important point is that uh llms are particularly successful at domains where the
- 38:05
language itself is the substrate of reasoning uh not for anything else yeah what would an llm like need to do to convince you uh otherwise so i mean like a zero shot agentic system right you have an agentic system give it a new problem it's not been trained to solve that particular problem