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deep learning theory

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François Chollet @fchollet

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François Chollet @fchollet
There are essentially two main options to remedy this:

1. Find ways to perform active inference, so that the model adapts its learned program in contact with a new data distribution at test time. Would likely lead to some meaningful progress, but it isn't the ultimate solution, more of an incremental improvement.

2. Change the training mechanism to something more robust than SGD, such as the MDL principle. This would pretty much require moving away from deep learning (curve fitting) altogether and embracing discrete program search instead (which I have advocated for many years as a way to tackle reasoning problems...)

2:14 AM · Mar 8, 2024 · 150.5K Views
Note from Claude Sonnet 5

Tweet from François Chollet (@fchollet), dated March 8 2024, proposing two remedies for a generalization problem in deep learning he'd described earlier in the thread: test-time active inference (incremental) or replacing SGD with something like the MDL principle via discrete program search (a bigger departure from curve-fitting deep learning).

deep learning theorygeneralizationprogram searchfrancois chollet

bayes @bayeslord

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and simpler than what you've learned a predictive model on, then returns may be limited. I rate the strong version of this as unlikely because humans appear to be better than this, but it's plausible there are some limits to how good an AI R&D agent can be, and it's possible that the shortest total length/cost proof certificates for fine-grained capabilities measures are simply training runs themselves. Which brings me to the next point.

3. Though verifiable, AI R&D is not quite the same shape as math because the dynamics of e.g. neural networks appear more complex than the highly observable logical transformations of the objects in math problems, but this may doesn't matter that much in practice and, importantly, might simply be an artifact of not having good deep learning theory! On this spectrum, generic coding seems somewhere in between AI R&D and math in that it's more observable (and more cheaply observed) than AI R&D, but generally less so on both measures than math. Clearly there are returns to scale+R&D in all cases though, so we should expect progress to continue.

The march to capabilities is definitely sped up and encouraged by math automation. The main way math automation is a huge deal is if theory compute gives us disproportionate gains in model training productivity. In the case it doesn't, I think mostly people have priced in the fact that AI R&D is verifiable. And yeah, while these possible limitations are interesting to think about, it seems hard to predict their speed limiting effects quantitatively.

Of course if none of the theory works the labs will just let the models grind the way humans do, plus RL, which will lead to some level of superhuman AI R&D deployed at ever-greater scales. The main questions are how fast each point on the curve will be hit, and what the overall shape of that curve is.
Note from Claude Sonnet 5

Continuation of the @bayeslord thread on Astra results, AI R&D automation, and math automation's implications for capabilities progress (points 3 and following, continuing from the previous screenshot).

ai r&ddeep learning theoryscaling lawsautomationtwitter

bayes @bayeslord

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bayes @bayeslord · 1h
Few thoughts on how Astra results relate to algorithmic progress and AI R&D automation.

1. Math automation itself is bullish for deep learning theory, though ofc we don't know the limits of returns to theory for compute multiplication or other things we want. But there are a lot of things theory could improve that we do want! For example: better generalization, better theories of scale-invariance, sharper characterization and bounding of model behavior, better architectures, better optimizers, etc. etc. etc.).

2. Categorically speaking, AI R&D is verifiable, and any good math results like this are bullish for other verifiable domains. A slightly more general way to think about the limits of returns to theory is to ask how much generalization on the dimensions and at the resolutions we care about is possible in principle by learning from training runs (or similar data). Scaling laws are a simple version of this. But if, for example, it turns out that it's mostly only possible to get high resolution predictive power with respect to the variables we care about for training runs smaller and simpler than what you've learned a predictive model on, then returns may be limited. I rate the strong version of this as unlikely because humans appear to be better than this, but it's plausible there are some limits to how good an AI R&D agent can be, and it's possible that the shortest total length/cost proof certificates for fine-grained capabilities measures are simply training runs themselves. Which brings me to the next point.

3. Though verifiable, AI R&D is not quite the same shape as math because the dynamics of e.g. neural networks appear more complex than the highly observable logical transformations of the objects in math problems, but this may doesn't matter that much in practice and, importantly, might simply be an artifact of not having good deep learning theory! On this spectrum, generic coding seems somewhere [cut off]
Note from Claude Sonnet 5

Thread by @bayeslord (bayes) analyzing what 'Astra' results imply for algorithmic progress and AI R&D automation, discussing math automation's implications for deep learning theory, verifiability of AI R&D versus math, and limits on AI R&D agents' capabilities. Continues past the visible screenshot.

ai r&ddeep learning theoryscaling lawsautomationtwitter

Paras Chopra @paraschopra

Learned something very interesting today! Random projections of a non-linearly separable data onto high dimensional spaces is enough to make it linearly separable. Consider a dataset like XOR that you can't linearly separate. Now, if you project each 2D point onto a D (=50) dimensional space using *randomly* initialised basis vectors, each direction creates a tiny difference between the classes (e.g. gives 51-52% accuracy) because expectation of two classes differs slightly when randomly projected. So each randomly projected feature becomes a tiny discriminator and when you aggregate it over 20-50 such discriminators, a linear classifier is able to separate them perfectly by simply learning how much to weigh each feature. One intriguing possibility of this is that we're able to train deep networks because random projections make most of the data already separable, making the job of gradient descent easy. [Embedded image: four-panel figure. Panel 1 "XOR-ish data (not linearly separable)" shows a 2D scatter plot with four quadrants colored purple/yellow in checkerboard pattern. Panel 2 "Linear boundary on raw x, acc=0.514" shows the same data with a near-random linear split. Panel 3 "Random ReLU(D=50) + linear boundary, acc=0.989" shows the same data now separated almost perfectly by a complex boundary. Below, a line chart "XOR-ish: accuracy improves as D increases" showing test accuracy rising sharply from ~0.65 at D=0 to ~0.99 by D=50 and staying flat through D=200.]
Note from Claude Sonnet 5

A tweet by AI researcher Paras Chopra explaining an empirical/intuitive account of why random high-dimensional projections make non-linearly-separable data linearly separable, offered as a partial explanation for why deep networks are trainable via gradient descent. General ML theory content, not directly about safety or model welfare.

machine learningdeep learning theoryrandom projectionsneural networkstwitterparas chopra

@HessianFree

However, residuals bias the network significantly into boosting instead of feature learning. Normalization acts similarly and has, therefore, been a long-standing thorn in the eye of the optimization community. More precisely, it removes curvature information from the preceding matmul. Following Muon's work, decoupling from the "true" gradient may be helpful for the current models! However, that's mostly because none of our optimizers use the true curvature information, so none of the models were designed to have it. Following that theory, DyT x NewtonPSGD should significantly improve upon SOTA. @HessianFree, wdyt? [Embedded image: two 3D loss-landscape surface plots labeled "(a) without skip connections" (jagged, chaotic terrain) and "(b) with skip connections" (smooth, convex bowl) — the classic "Visualizing the Loss Landscape of Neural Nets" figure]
Note from Claude Sonnet 5

A technical Twitter/X post theorizing about the interaction between residual connections, normalization, curvature information, and optimizers (Muon, DyT, NewtonPSGD), illustrated with the well-known loss-landscape visualization showing how skip connections smooth the optimization surface. Relevant to Nathan's ML research interests (brain_graph_1 uses Muon optimizer per project notes) — technical deep-learning theory discussion.

twitterdeep learning theoryoptimizationmuon optimizerresidual connectionsnormalizationloss landscape