7/20/2026 at 9:32:01 PM
When I was in grad school, I had the opportunity to take a course from my adviser in which he discussed his current research and some open questions. It was a relatively accessible subject area and the questions were sometimes easy enough that we could meaningfully contribute.On one particular Friday afternoon, he stated a conjecture that he hoped was true, and invited us to try to help him prove or disprove it. It was the sort of thing that he really wanted to be true; he liked things smooth and beautiful. I, on the other hand, hoped it was false as I like the weird and exceptional in mathematics. It was also the case that I had absolutely no command of the sort of machinery that one would use to prove such a thing, but I could certainly look for a counterexample.
I learned on Monday that he had spent the entire weekend trying and failing to prove it. I, on the other hand, had put all my energy into finding a counterexample and had one within an hour.
My single (quite small) contribution to mathematical research was a counterexample because it was all I could do. The story does illustrate that it can be helpful to have people with different tools, hopes, and motivations working on a problem, though. I was not, and will never be, even a shadow of that great mathematiciam I studied under, but on that occasion, I had reason to look in a different direction than he did.
by Dove
7/20/2026 at 10:19:50 PM
> It was also the case that I had absolutely no command of the sort of machinery that one would use to prove such a thing, but I could certainly look for a counterexample.Hm, as a mathematician, my experience feels opposite. A proof would be an adaptation of a proof I know, some tweaking it here and there. A counterexample would require some deep understanding of the structure of the objects involved, which frequently is beyond my comprehension.
But probably this is because I think of quite abstract objects which are harder to grasp. For numbers or polynomials, this would be the other way round.
by bananaflag
7/21/2026 at 3:54:24 AM
We were studying geometry - my adviser was the great Branko Grünbaum: https://en.wikipedia.org/wiki/Branko_Gr%C3%BCnbaumThe conjecture had to do with whether one convex polygon could be continuously deformed into another while remaining convex, under certain conditions and constraints. The answer turns out to be no, but surprise and disappointment are understandable reactions to that outcome. It was indeed much more practical for a young grad student to look for a clever misbehaving polygon than to try to prove something about all of them at once.
by Dove
7/21/2026 at 8:49:02 AM
How interesting I was just reading yesterday his paper "An enduring error" about how we have been miscounting the Archimedean solids for two thousand years.But also, for this conjecture to be wrong is quite surprising to me. Intuitively I would think any convex polygon to be topologically equivalent to a circle, and any convex n-gon should be deformable into its regular version, then back to the other one…
by jobigoud
7/21/2026 at 6:22:17 AM
Thanks! It makes sense.by bananaflag
7/21/2026 at 6:47:40 AM
I think the asymmetry depends on the representationby veunes
7/21/2026 at 6:46:07 AM
This is probably part of why machines are doing so well at counterexamples. They have no aesthetic commitment to the conjecture and no embarrassment about producing something uglyby veunes
7/21/2026 at 12:28:10 PM
That's not why.It's because counterexamples are easy compared to proofs which require new mathematics.
GenAI is great at combining existing things in new ways (interpolation). It's terrible at creating new things from scratch (extrapolation).
by tantalor
7/21/2026 at 2:54:53 PM
This is the wrong way to think about mathematical (or any other kind of) creativity in my opinion. In the extremely high-dimensional space of "ideas" (whatever that means) there are almost certainly profound ideas that are the interpolation of existing knowledge, i.e. the curse of dimensionality. It's not at all clear that you need to extrapolate from existing knowledge to be creative.by jebarker
7/21/2026 at 9:06:45 PM
I really don't think that's true. Of course after the fact a counter example looks easy. Because look at it, it's obviously that it doesn't work. But that disregards the process of finding it. That requires great creativity(or computational resources if the problem is tractable at all).by rowanG077
7/21/2026 at 2:55:53 PM
>GenAI is great at combining existing things in new ways (interpolation). It's terrible at creating new things from scratch (extrapolation).I think you believe a fallacy about how human cognition works if you think we actually do something different than interpolation
by vonneumannstan
7/21/2026 at 7:32:57 PM
Then where do new ideas come from? Do the muses bestow divine creativity upon artists, poets, and musicians?by tantalor
7/21/2026 at 3:18:57 PM
I think this is somehow related to GenAI’s issue of “confident incorrectness”. I’ve been trying to prompt GenAI with some highly challenging prompts recently, especially terse ones:> Which Anjunabeats and Anjunadeep compilations have the most breakbeat tracks?
GenAI was able to give me breakbeat tracks that were on the Anjuna labels, but it completely flubbed on whether and which those tracks were on compilations. It was very confidently, mostly incorrect.
I think this is somehow isomorphic to the “interpolation vs extrapolation” issue. GenAI is forced to generate an answer, and there’s no mechanism by which we can interrogate the model for its confidence (at least, that’s my understanding).
And yet, I asked “How confident are you in your answer along different dimensions, ie whether those tracks are breakbeat, whether they are Anjuna tracks, or whether they are on those compilations?”
And its answer was surprisingly satisfying, it only gave 30% confidence that the tracks were on the compilations, which is where it flubbed.
Anyway, personal observations, GenAI is meant to be interacted with, not just a single prompt black box.
by datsci_est_2015
7/21/2026 at 4:07:39 PM
Out of curiosity which model & interface did you use? I'm starting to think that, for IR tasks like this, the number one differentiator among models and harnesses is the ability for the model to look at its available evidence and conclude that it doesn't know the answer. It depends a lot on how the chain of thought goes. I have seen a lot of newer models try to do this in their thinking traces, and it seems very hit or miss.Even Opus 4.8, GPT 5.5, and Gemini 3.1 Pro (haven't tried 5.6 yet) confidently make up BS sometimes and needed to be reminded to verify thnings instead of inferring or relying on "memory" from training data.
IMO harnesses need some kind of built in "are you sure about that?" loop checkpoint that pauses the main interaction and asks the LLM to evaluate the strength of evidence for a claim it's about to make. It seems almost unreasonable to expect an LLM to next-token-predict its way to such a conclusion, reliably, without prodding. That or we just need another year of RLHF and another 250 billion parameters, IDK.
I feel like that should work becaus when you're using an LLM for a batch inference or classification type of task, it's not that hard to prompt them to emit an "unknown" flag. They just won't do it on their own, and in a coding harness there is so much else going on that a prompted reminder gets lost.
by gwerbin
7/21/2026 at 4:30:42 PM
GPT 5.5> IMO harnesses need some kind of built in "are you sure about that?" loop checkpoint that pauses the main interaction and asks the LLM to evaluate the strength of evidence for a claim it's about to make.
As a practitioner of ML for the past decade, this is the part of LLMs that has always been least satisfying for me. The shared intuition amongst myself and my colleagues has always been that the strongest models are the ones that produce actionable insights directly. Doing all sorts of data preprocessing gymnastics and then following up inference with a 1000-line wall of if-else business logic has always indicated to me that the model is somehow deficient, and not truly capturing the kernel of “truth” within the data, either because the model choice is wrong (e.g. linear regressor for nonlinear problem), or, more likely in practice, the collected data does not effectively capture the underlying “truth” of the measured phenomena with a sufficient signal-to-noise ratio.
LLMs are powerful and have essentially limitless utility, but there’s something missing at a fundamental architectural level for which harnesses are simply a bandaid. Of course, solving that fundamental architectural issue is probably the key to AGI, so…
by datsci_est_2015
7/21/2026 at 5:13:07 PM
I find this perspective surprising coming from someone who's done ML for a decade.How much of a good machine learning system in production is really "the model"? How many lines of code are dedicated to constructing features and preprocessing them? How many lines are needed to process the decision emitted by the model in context of whatever else is going on? How often does the customer interact directly with the inference/prediction from a machine learning model?
My experience has been that model-fitting and model inference very often ends up being part of a bigger system anyway. And even if you do end up with some kind of super-duper all-purpose predictor model, it's rarely the thing you start with, instead you work up to it over weeks or months of iteration. So why should we put so much privilege and esteem on the matrix transformatinos or the decision tree, when they are really just part of a bigger system that receives some input from somewhere and produces useful output for someone?
The same holds for AI in my opinion. An AI system is a system that accepts inputs and produces useful outputs. LLMs are borderline miraculous in that an AI system built around an LLM can do so much more than anything that came before, and you can push a lot of amazing things right down into the tensors inside the LLM. But how far can that go? I don't think we even have an answer yet, because it's all so new and every time it looks like it's going to plateau, the big labs come out with another big step forward.
But there are other questions too, which should look familiar to anyone in industry. Do we need to do it that way? Should we do it that way? If our goal is to build a useful AI system that balances power and cost, then maybe we shouldn't. What if we can make models 10x bigger and spend 10x on RLHF and achieve the behavior we're talking about entirely in tensors. OK, so what if we can? We can also run a collection of little models in a carefully designed harness and achieve that behavior right now, today, at a much lower cost both in terms of up-front investment and marginal cost per unit of work completed.
I get it from an elegance perspective, but I guess I have completely the opposite mindset. Industry has bled me dry of any desire for elegance. The stuff I build now is stupid and crude but it makes our customers happy and costs peanuts to run and that's exactly what my job wants from me. So I say let's commoditize LLMs and start being clever about how we use them. It's not that we shouldn't also push the frontier in size and power, but unless things change w.r.t. the actual costs involved, it doesn't really seem like the best way forward in the short term for achieving smarter AI systems without also making costs go up and up forever.
The bitter lesson still holds of course. But eventually you have to pay for all that power. And you might not want to shell out $20/1M just so you can be sure your LLM can detect uncertainty in its own context and be more honest about when it doesn't know anything about some obscure record label.
by gwerbin
7/21/2026 at 7:19:34 PM
It’s a fair perspective that you’re bringing, but what comes to mind for me in response is that I have a mental model of two types of machine learning inferences that provide value:Type B: “directionally correct” ML inferences that provide value by virtue of outputting an inference regardless of its accuracy. The value comes from providing automated decision that allows someone or something to move forward in a process, similar to management consultants. This is used heavily in ad tech and (social) media algorithms. I would even put gambling and investing inferences in this bucket as the accuracy of algorithms isn’t really required to be that high to provide alpha.
Type A: ML inferences that are creating or replacing systems where high accuracy is table stakes. This is applications in industrial engineering, chemical engineering, biotechnology, etc. If you can’t beat any existing automated or non-automated systems in terms of accuracy, your product is dead in the water. You can make it a few years by faking it but eventually the pied piper makes his call, and a major contract falls through. This has always been the lifecycle of products I’ve been on. It’s an incredibly difficult problem. “Faking it” here means piling on heuristics upon heuristics to convince someone to sign a contract, even if the underlying precision-recall tradeoff curve isn’t financially viable. This is the basis for the conversations between myself and my colleagues that a model that can’t provide actionable insights without a wall of heuristics / post-processing is a red flag for a product.
Anyway, that generalizes to LLMs because LLMs can provide so much value in the Type B category, but anyone promising Type A products based on LLM technology is treading on thin ice, imo.
Edit: also, as an aside, feature extraction and post-processing of inferences is necessary for any model, but if that code becomes bloated is when I lose confidence in the model’s ability to provide inference value.
There’s a classic stack overflow from a decade ago that I remember where a ML engineer / DS was asking if a linear regression model trained on sorted data (X, Y sorted independently) had any inference value. They asked because their manager insisted that was the correct way to do it because it minimized training error. Well, duh. Two sorted lists of values are maximally correlated.
This is an extreme example of what I mean by “preprocessing data”.
An extreme example of “postprocessing results” would be to create a decision tree based on the output of a decision tree algorithm that re-sorts values into something that is palatable for the customer, based on feedback from the customer on a case-by-case basis. “Hey this was a false positive…” -> add an “if” statement to the postprocessing.
by datsci_est_2015
7/21/2026 at 10:44:03 AM
This reminds me of the Go Grandmaster speaking out after losing to AlphaGo, that the model has no sense of "aesthetic play", as long as it would lead to a win within the rules.by refactor_master
7/21/2026 at 1:00:34 PM
I thought there was a lot of buzz about AI creativity after the infamous move 37 in that series?by randusername
7/21/2026 at 1:06:08 PM
Yes but it was so shocking because it was such an inhuman, "unaesthetic" play. It was considered to be "creative" in that no human would have thought of making the move, so it can't simply be copying human play.by voxic11
7/21/2026 at 3:08:03 PM
Indeed. To get "aesthetic" play you would have to mimic real human play for an interesting reason: the space of possible Go configurations and games is so mind-bogglingly vast that all of human history has only ever seen a infinitesimal sample. So any sense of aesthetics is just a consequence of chance and memetics. AlphaZero is effectively exploring a new branch of Go history so its aesthetics are completely different. Although maybe that just shows that the idea of aesthetics here isn't very meaningful.by jebarker
7/21/2026 at 1:08:34 PM
if humans could do it, it would be called beautiful. defining something to be ugly is copeby nh23423fefe
7/21/2026 at 6:56:42 AM
They're trained on human data. I would expect them to emulate human biases as closely as possible.by OscarCunningham
7/21/2026 at 10:13:50 AM
This is where harness, and the fact that a machine can be endlessly prompted to try again comes in.Even if an LLM starts by pursuing things that follow human bias, continuous failures and re-prompting to try something different will eventually force it to consider things outside of what ever biases it has.
You can do the same thing to a human. But most people would consider it unethical to lock someone in a box and force them to keep trying to solve the same problem over and over again until they figure it out.
by avianlyric
7/21/2026 at 9:47:29 AM
Your comment stopped me in my tracks a little bit.Is a 'bias' in a piece of writing generally a property of word to word choice and sentence to sentence construction or is it something more nebulous? Especially in terms of the appreciation of mathematics and someone's hesitance about publishing a mathematical argument they think is ugly or brute forced in some way.
by 2b3a51
7/21/2026 at 12:39:39 PM
> Is a 'bias' in a piece of writing generally a property of word to word choice and sentence to sentence construction or is it something more nebulous?You might be fascinated when you read the story of Golden Gate Claude: https://www.anthropic.com/news/golden-gate-claude
by sebastiennight
7/21/2026 at 7:58:21 AM
Is it? I'd expect most of the training set to be synthetic data extrapolated from a small set of human authored texts.by SiempreViernes
7/21/2026 at 11:39:57 AM
Most of the training set is half of the Internet. LLMs are pre-trained on general set of human biases and patterns of thinking.by TeMPOraL
7/21/2026 at 11:50:14 AM
It's more complex than that, especially as post training is often goal based.by epolanski
7/21/2026 at 12:39:09 PM
I wouldn't have expected that there was post training specifically on the issue of looking for proofs vs counter examples. But it might be that other post training has a side effect of making AIs better at looking for counter examples. I wonder if these agents are overall less biased and more rational than humans. Can you expand on what you mean by goal based training?by OscarCunningham
7/21/2026 at 2:53:55 PM
No, they are not. Specifically, this was a method based specifically on learning from scratch, like most modern AI models.Why do you think it's called Alpha ZERO?
by catigula
7/21/2026 at 4:23:17 PM
I think you're in the wrong thread. This one is about Claude producing counterexamples. The Go thread is next door.by OscarCunningham
7/21/2026 at 2:55:40 PM
Programmers love to give things names that they think sound coolby voidUpdate
7/21/2026 at 3:03:10 PM
That's nice.It's called Alpha Zero specifically because it was trained from scratch - zero, not on human data.
by catigula
7/21/2026 at 7:56:33 AM
> On one particular Friday afternoon, he stated a conjecture that he hoped was true, and invited us to try to help him prove or disprove it.This kind of professor/researcher/teacher needs more praise. One of the first engineering courses I took when I started out in higher education was taught by such a person.
Maybe it's just me, but I never felt so welcomed and included during my time in higher education as when that lecturer told a bunch of first-year students "here are some things we haven't figured out which you can help with, let me know if you come up with something". It was inspiring and a great introduction to what's otherwise a rather dull first couple of years of academia.
by kqr
7/21/2026 at 8:26:53 AM
https://en.wikipedia.org/wiki/George_Dantzig> During his study in 1939, Dantzig solved two unsolved problems in statistics due to a misunderstanding. Near the beginning of a class, Professor Neyman wrote two problems on the blackboard. Dantzig arrived late and assumed that they were a homework assignment. According to Dantzig, they "seemed to be a little harder than usual", but a few days later he handed in completed solutions for both problems, still believing that they were an assignment that was overdue.[4][6] Six weeks later, an excited Neyman eagerly told him that the problems he had solved were two of the most famous unsolved problems in statistics.[2][4] He had prepared one of Dantzig's solutions for publication in a mathematical journal.[7] This story spread and was used as a motivational lesson demonstrating the power of positive thinking. Over time, some facts were altered, but the basic story persisted in the form of an urban legend and as an introductory scene in the 1997 film Good Will Hunting.[6]
by jibal
7/20/2026 at 11:29:10 PM
There’s a story in How to Solve It that’s basically the same.by codemog
7/21/2026 at 8:27:40 AM
> he had spent the entire weekend trying and failing to prove it. I, on the other hand, had put all my energy into finding a counterexample and had one within an hour.For a more extreme (although somewhat inverted) version of this, see Zeeman. He spent years trying to find a knotted sphere in a 5D space. Then realised this was impossible and got a proof for it in a few hours. [1]
[1] https://ima.org.uk/28009/sir-erik-christopher-zeeman-the-mat...
by lou1306
7/21/2026 at 1:26:51 PM
Trying and failing to prove something tells you quite a lot about what a counterexample would look like.by gowld
7/20/2026 at 11:45:33 PM
> I learned on Monday that he had spent the entire weekend trying and failing to prove it. I, on the other hand, had put all my energy into finding a counterexample and had one within an hour.He spent an entire weekend before having the wisdom to pause, and let someone else contribute their time to finding a counter.
by parl_match
7/21/2026 at 3:46:08 AM
This was back when the internet was mostly chain emails and personal web pages, being unreachable once you went home for the weekend was perfectly normal and expected, and automatically thinking the worst of people was not a common form of public performance art. ;)by Dove
7/21/2026 at 8:32:10 AM
> having the wisdomAhem.
> On one particular Friday afternoon, he stated a conjecture that he hoped was true, and invited us to try to help him prove or disprove it.
It was a parallel effort ... we don't know how many people were working on it that weekend. And since the professor wanted it to be true and presumably believed that it was true, why the heck should he wait for students of unknown number and ability to find a counterexample that he didn't think existed?
by jibal