1,777 karma · joined March 11, 2015
https://people.mpim-bonn.mpg.de/zagier/files/math-mag/63-2/f...
(My favorite line: "Levasseur analyzes the game and shows that on average you will have a score of n + (sqrt(pn) - 1)/2 + O(1/sqrt(n)) while the kid will have exactly n. We maintain, however, that only the most degenerate parent would play against a two-year-old for money, so the question should be not by how much you expect to win, but with what probability you will win at all.")
I dunno man. Not writing a 3000 word email is one thing, but if you make a power point an then don't share it electronically, it smells like you are cajoling students to attend your lectures in order to stroke your ego. These people are paying a lot of money to attend your course; if they feel that they would get more value out of looking at your power point without attending your lectures that is not something that should be sneered away. Both as an undergraduate student and a graduate TA I was always very put off by this kind of high-handed bullying instructors would engage in to juice attendance of their courses. Just teach well and evaluate accurately. That's what they're paying you for. They're not paying for you to harass them into being at some inconvenient place at a particular time every Monday, Wednesday, and Friday.
Deep neural nets are notable for their strong generalization performance: despite being highly overparametrized they do not seem to overfit the training data. They still perform well on hold-out data and very often on out of distribution data "in the wild". The paper [0] noted a particularly odd feature of neural net training: one can train neural nets on standard datasets to fit random labels. There does not seem to be an inductive bias strong enough to rule out bad overfitting. It is in principle possible to train a model which performs perfectly on the training data but gives nonsense on the test data. But this doesn't seem to happen in practice.
The submission argues that this is unsurprising, and fits within standard theoretical frameworks for machine learning. In section 4 it is claimed that this kind of thing ("benign overfitting") is common to any learning algorithm with "a flexible hypothesis space, combined with a loss function that demands we fit the data, and a simplicity bias: amongst solutions that are consistent with the data (i.e., fit the data perfectly), the simpler ones are preferred".
The fact that the third of these conditions is satisfied, however, is non-trivial, and in my opinion is still not well understood. The results of [0] are reproducible with a wide variety of architectures, with or without any form of explicit regularization. If there is an inductive bias toward "simpler solutions" in fitting deep neural nets it has to come either from SGD itself or from some bias which is very generic in architecture. It's not something like "CNNs generalize well on image data because of an inductive bias toward translation invariant features." While there is some work on implicit smoothing by SGD, for example, in my opinion this is not sufficient to explain the phenomena observed in [0]. What I would find satisfying is a reproducible ablation study of neural net training that removed benign overfitting (+), so that it was clear what exactly are the necessary and sufficient conditions for this behavior in the context of neural nets. As far as I know this still has never been done, because it is not known what this would even entail.
(+) To be clear, I think this would not look like "the fit model still generalizes, but we can no longer fit random labels" but rather "the fit model now gives nonsense on holdout data".
https://www.imf.org/external/datamapper/PPPSH@WEO/EU/CHN/USA
Edit: if you think message boards and blogs were too specific, here are a couple of other media with this property: radio and television.
But I've been hearing the refrain of this article for a decade now. I just don't believe it anymore.
I don't find this very impressive. Forget LLMs for a second. Let's say _you_ read a question of that kind with some bit of irrelevant information. There are two possibilities you have to consider: the question may as well have excluded the irrelevant information, or the question was miswritten and the irrelevant information was meant to be relevant. The latter is a perfectly live possibility, and I don't think it's a dramatic failure to assume that this is correct. I have to confess that when I read some people's LLM gotcha questions, where they take some popular logic puzzle and invert things, I think I would get them "wrong" too. And not wrong because I don't understand the question, but wrong because with no context I'd just assume the inversion was a typo.
I bring this up because I believe that at the time catastrophe theory was seen as a "widely-applicable science of systems". Or at least some practitioners tried to sell it as such. This point of view eventually soured to the detriment of catastrophe theory, which cleared out. I don't think this was a good thing: catastrophe theory (the study of the singularities of smooth maps and their consequences to dynamical systems) is an interesting topic with many remaining open questions. But it was seen as cringe that people were, e.g., using Whitney's classification of the generic singularities of planar maps to try to say something about predator/prey dynamics or whatever. Any claim about applications of catastrophe theory was infected with this stink, and so people lost interest in it.