You know what's crazy? That all of this is real. Meaning what? Don't you think so? All this AI stuff and all this Bay Area… that it's happening. Isn't it straight out of science fiction? Another thing that's crazy is how normal the slow takeoff feels. The idea that we'd be investing 1% of GDP in AI, I feel like it would have felt like a bigger deal, whereas right now it just feels... We get used to things pretty fast, it turns out. But also it's kind of abstract. What does it mean? It means that you see it in the news, that such and such company announced such and such dollar amount. That's all you see. It's not really felt in any other way so far. Should we actually begin here? I think this is an interesting discussion. Sure. I think your point, about how from the average person's point of view nothing is that different, will continue being true even into the singularity. No, I don't think so. Okay, interesting. The thing which I was referring to not feeling different is, okay, such and such company announced some difficult-to-comprehend dollar amount of investment. I don't think anyone knows what to do with that.
But I think the impact of AI is going to be felt. AI is going to be diffused through the economy. There'll be very strong economic forces for this, and I think the impact is going to be felt very strongly. When do you expect that impact? I think the models seem smarter than their economic impact would imply. Yeah. This is one of the very confusing things about the models right now. How to reconcile the fact that they are doing so well on evals?
You look at the evals and you go, "Those are pretty hard evals." They are doing so well. But the economic impact seems to be dramatically behind. It's very difficult to make sense of, how can the model, on the one hand, do these amazing things, and then on the other hand, repeat itself twice in some situation? An example would be, let's say you use vibe coding to do something. You go to some place and then you get a bug. Then you tell the model, "Can you please fix the bug?" And the model says, "Oh my God, you're so right. I have a bug. Let me go fix that." And it introduces a second bug. Then you tell it, "You have this new second bug," and it tells you, "Oh my God, how could I have done it? You're so right again," and brings back the first bug, and you can alternate between those. How is that possible? I'm not sure, but it does suggest that something strange is going on. I have two possible explanations. The more whimsical explanation is that maybe RL training makes the models a little too single-minded and narrowly focused, a little bit too unaware, even though it also makes them aware in some other ways.
Because of this, they can't do basic things. But there is another explanation. Back when people were doing pre-training, the question of what data to train on was answered, because that answer was everything. When you do pre-training, you need all the data. So you don't have to think if it's going to be this data or that data. But when people do RL training, they do need to think. They say, "Okay, we want to have this kind of RL training for this thing and that kind of RL training for that thing." From what I hear, all the companies have teams that just produce new RL environments and just add it to the training mix.
The question is, well, what are those? There are so many degrees of freedom. There is such a huge variety of RL environments you could produce. One thing you could do, and I think this is something that is done inadvertently, is that people take inspiration from the evals. You say, "Hey, I would love our model to do really well when we release it. I want the evals to look great. What would be RL training that could help on this task?" I think that is something that happens, and it could explain a lot of what's going on.
If you combine this with generalization of the models actually being inadequate, that has the potential to explain a lot of what we are seeing, this disconnect between eval performance and actual real-world performance, which is something that we don't today even understand, what we mean by that. I like this idea that the real reward hacking is the human researchers who are too focused on the evals. I think there are two ways to understand, or to try to think about, what you have just pointed out. One is that if it's the case that simply by becoming superhuman at a coding competition, a model will not automatically become more tasteful and exercise better judgment about how to improve your codebase, well then you should expand the suite of environments such that you're not just testing it on having the best performance in coding competition. It should also be able to make the best kind of application for X thing or Y thing or Z thing. Another, maybe this is what you're hinting at, is to say, "Why should it be the case in the first place that becoming superhuman at coding competitions doesn't make you a more tasteful programmer more generally?" Maybe the thing to do is not to keep stacking up the amount and diversity of environments, but to figure out an approach which lets you learn from one environment and improve your performance on something else. I have a human analogy which might be helpful. Let's take the case of competitive programming, since you mentioned that. Suppose you have two students. One of them decided they want to be the best competitive programmer, so they will practice 10,000 hours for that domain. They will solve all the problems, memorize all the proof techniques, and be very skilled at quickly and correctly implementing all the algorithms. By doing so, they became one of the best. Student number two thought, "Oh, competitive programming is cool." Maybe they practiced for 100 hours, much less, and they also did really well. Which one do you think is going to do better in their career later on? The second. Right. I think that's basically what's going on. The models are much more like the first student, but even more. Because then we say, the model should be good at competitive programming so let's get every single competitive programming problem ever. And then let's do some data augmentation so we have even more competitive programming problems, and we train on that. Now you've got this great competitive programmer.
With this analogy, I think it's more intuitive. Yeah, okay, if it's so well trained, all the different algorithms and all the different proof techniques are right at its fingertips. And it's more intuitive that with this level of preparation, it would not necessarily generalize to other things. But then what is the analogy for what the second student is doing before they do the 100 hours of fine-tuning? I think they have "it." The "it" factor. When I was an undergrad, I remember there was a student like this that studied with me, so I know it exists.
I think it's interesting to distinguish "it" from whatever pre-training does. One way to understand what you just said about not having to choose the data in pre-training is to say it's actually not dissimilar to the 10,000 hours of practice. It's just that you get that 10,000 hours of practice for free because it's already somewhere in the pre-training distribution. But maybe you're suggesting there's actually not that much generalization from pre-training. There's just so much data in pre-training, but it's not necessarily generalizing better than RL. The main strength of pre-training is that: A, there is so much of it, and B, you don't have to think hard about what data to put into pre-training. It's very natural data, and it does include in it a lot of what people do: people's thoughts and a lot of the features. It's like the whole world as projected by people onto text, and pre-training tries to capture that using a huge amount of data. Pre-training is very difficult to reason about because it's so hard to understand the manner in which the model relies on pre-training data.
Whenever the model makes a mistake, could it be because something by chance is not as supported by the pre-training data? "Support by pre-training" is maybe a loose term. I don't know if I can add anything more useful on this. I don't think there is a human analog to pre-training. Here are analogies that people have proposed for what the human analogy to pre-training is. I'm curious to get your thoughts on why they're potentially wrong. One is to think about the first 18, or 15, or 13 years of a person's life when they aren't necessarily economically productive, but they are doing something that is making them understand the world better and so forth. The other is to think about evolution as doing some kind of search for 3 billion years, which then results in a human lifetime instance. I'm curious if you think either of these are analogous to pre-training. How would you think about what lifetime human learning is like, if not pre-training? I think there are some similarities between both of these and pre-training, and pre-training tries to play the role of both of these. But I think there are some big differences as well. The amount of pre-training data is very, very staggering. Yes.
Somehow a human being, after even 15 years with a tiny fraction of the pre-training data, they know much less. But whatever they do know, they know much more deeply somehow. Already at that age, you would not make mistakes that our AIs make. There is another thing. You might say, could it be something like evolution? The answer is maybe. But in this case, I think evolution might actually have an edge. I remember reading about this case. One way in which neuroscientists can learn about the brain is by studying people with brain damage to different parts of the brain.
Some people have the most strange symptoms you could imagine. It's actually really, really interesting. One case that comes to mind that's relevant. I read about this person who had some kind of brain damage, a stroke or an accident, that took out his emotional processing. So he stopped feeling any emotion. He still remained very articulate and he could solve little puzzles, and on tests he seemed to be just fine. But he felt no emotion. He didn't feel sad, he didn't feel anger, he didn't feel animated. He became somehow extremely bad at making any decisions at all. It would take him hours to decide on which socks to wear. He would make very bad financial decisions. What does it say about the role of our built-in emotions in making us a viable agent, essentially? To connect to your question about pre-training, maybe if you are good enough at getting everything out of pre-training, you could get that as well. But that's the kind of thing which seems...
Well, it may or may not be possible to get that from pre-training. What is "that"? Clearly not just directly emotion. It seems like some almost value function-like thing which is telling you what the end reward for any decision should be. You think that doesn't sort of implicitly come from pre-training? I think it could. I'm just saying it's not 100% obvious.
But what is that? How do you think about emotions? What is the ML analogy for emotions? It should be some kind of a value function thing. But I don’t think there is a great ML analogy because right now, value functions don't play a very prominent role in the things people do. It might be worth defining for the audience what a value function is, if you want to do that. Certainly, I'll be very happy to do that. When people do reinforcement learning, the way reinforcement learning is done right now, how do people train those agents?
You have your neural net and you give it a problem, and then you tell the model, "Go solve it." The model takes maybe thousands, hundreds of thousands of actions or thoughts or something, and then it produces a solution. The solution is graded. And then the score is used to provide a training signal for every single action in your trajectory. That means that if you are doing something that goes for a long time—if you're training a task that takes a long time to solve—it will do no learning at all until you come up with the proposed solution.
That's how reinforcement learning is done naively. That's how o1, R1 ostensibly are done. The value function says something like, "Maybe I could sometimes, not always, tell you if you are doing well or badly." The notion of a value function is more useful in some domains than others. For example, when you play chess and you lose a piece, I messed up. You don't need to play the whole game to know that what I just did was bad, and therefore whatever preceded it was also bad. The value function lets you short-circuit the wait until the very end.
Let's suppose that you are doing some kind of a math thing or a programming thing, and you're trying to explore a particular solution or direction. After, let's say, a thousand steps of thinking, you concluded that this direction is unpromising. As soon as you conclude this, you could already get a reward signal a thousand timesteps previously, when you decided to pursue down this path. You say, "Next time I shouldn't pursue this path in a similar situation," long before you actually came up with the proposed solution. This was in the DeepSeek R1 paper— that the space of trajectories is so wide that maybe it's hard to learn a mapping from an intermediate trajectory and value. And also given that, in coding for example you'll have the wrong idea, then you'll go back, then you'll change something. This sounds like such lack of faith in deep learning. Sure it might be difficult, but nothing deep learning can't do. My expectation is that a value function should be useful, and I fully expect that they will be used in the future, if not already. What I was alluding to with the person whose emotional center got damaged, it’s more that maybe what it suggests is that the value function of humans is modulated by emotions in some important way that's hardcoded by evolution.
And maybe that is important for people to be effective in the world. That's the thing I was planning on asking you. There's something really interesting about emotions of the value function, which is that it's impressive that they have this much utility while still being rather simple to understand. I have two responses. I do agree that compared to the kind of things that we learn and the things we are talking about, the kind of AI we are talking about, emotions are relatively simple. They might even be so simple that maybe you could map them out in a human-understandable way.
I think it would be cool to do. In terms of utility though, I think there is a thing where there is this complexity-robustness tradeoff, where complex things can be very useful, but simple things are very useful in a very broad range of situations. One way to interpret what we are seeing is that we've got these emotions that evolved mostly from our mammal ancestors and then fine-tuned a little bit while we were hominids, just a bit.
We do have a decent amount of social emotions though which mammals may lack. But they're not very sophisticated. And because they're not sophisticated, they serve us so well in this very different world compared to the one that we've been living in. Actually, they also make mistakes. For example, our emotions… Well actually, I don’t know. Does hunger count as an emotion? It's debatable. But I think, for example, our intuitive feeling of hunger is not succeeding in guiding us correctly in this world with an abundance of food.
People have been talking about scaling data, scaling parameters, scaling compute. Is there a more general way to think about scaling? What are the other scaling axes? Here's a perspective that I think might be true. The way ML used to work is that people would just tinker with stuff and try to get interesting results. That's what's been going on in the past. Then the scaling insight arrived. Scaling laws, GPT-3, and suddenly everyone realized we should scale. This is an example of how language affects thought. "Scaling" is just one word, but it's such a powerful word because it informs people what to do. They say, "Let's try to scale things." So you say, what are we scaling? Pre-training was the thing to scale. It was a particular scaling recipe. The big breakthrough of pre-training is the realization that this recipe is good.
You say, "Hey, if you mix some compute with some data into a neural net of a certain size, you will get results. You will know that you'll be better if you just scale the recipe up." This is also great. Companies love this because it gives you a very low-risk way of investing your resources. It's much harder to invest your resources in research. Compare that. If you research, you need to be like, "Go forth researchers and research and come up with something", versus get more data, get more compute.
You know you'll get something from pre-training. Indeed, it looks like, based on various things some people say on Twitter, maybe it appears that Gemini have found a way to get more out of pre-training. At some point though, pre-training will run out of data. The data is very clearly finite. What do you do next? Either you do some kind of souped-up pre-training, a different recipe from the one you've done before, or you're doing RL, or maybe something else. But now that compute is big, compute is now very big, in some sense we are back to the age of research. Maybe here's another way to put it.
Up until 2020, from 2012 to 2020, it was the age of research. Now, from 2020 to 2025, it was the age of scaling—maybe plus or minus, let's add error bars to those years—because people say, "This is amazing. You've got to scale more. Keep scaling." The one word: scaling. But now the scale is so big. Is the belief really, "Oh, it's so big, but if you had 100x more, everything would be so different?" It would be different, for sure. But is the belief that if you just 100x the scale, everything would be transformed? I don't think that's true. So it's back to the age of research again, just with big computers. That's a very interesting way to put it. But let me ask you the question you just posed then. What are we scaling, and what would it mean to have a recipe? I guess I'm not aware of a very clean relationship that almost looks like a law of physics which existed in pre-training. There was a power law between data or compute or parameters and loss. What is the kind of relationship we should be seeking, and how should we think about what this new recipe might look like?







