This point is very well made: 'local generalization vs. extreme generalization.' Advanced NN's today can locally generalize quite well and there's a lot of research spent to inch their generalization further out. This will probably be done by increasing NN size or increasing the NN building-blocks complexity.
Or maybe increasing NN size/complexity is the 21st century version of adding epicycles to make geocentrism work. http://wiki.c2.com/?AddingEpicycles
The Limitations of Deep Learning
261–270 of 296 posts
Re: The Limitations of Deep Learning
#262This article is a bit misleading. I believe NNs are a lot like the human brain. But just the lowest level of our brain. What psychologists might call "procedural knowledge". Example: learning to ride a bike. You have no idea how you do it. You can't explain it in words. It requires tons of trial and error. You can give a bike to a physicist that has a perfect deep understanding of the laws of physics. And they won't…
It's a bit unclear whether Fchollet is asserting that (A) Deep Learning has fundamental theoretical limitations on what it can achieve, or rather (B) that we have yet to discover ways of extracting human-like performance from it.
Certainly I agree with (B) that the current generation of models are little more than 'pattern matching', and the SOTA CNNs are, at best, something like small pieces of visual cortex or insect brains. But rather than deriding this limitation I'm more impressed at the range of tasks "mere" pattern matching is able to do so well - that's my takeaway.
But I also disagree with the distinction he makes between "local" and "extreme" generalization, or at least would contend that it's not a hard, or particularly meaningful, epistemic distinction. It is totally unsurprising that high-level planning and abstract reasoning capabilities are lacking in neural nets because the tasks we set them are so narrowly focused in scope. A neural net doesn't have a childhood, a desire/need to sustain itself, it doesn't grapple with its identity and mortality, set life goals for itself, forge relationships with others, or ponder the cosmos. And these types of quintessentially human activities are what I believe our capacities for high-level planning, reasoning with formal logic etc. arose to service. For this reason it's not obvious to me that a deep-learning-like system (with sufficient conception of causality, scarcity of resources, sanctity of life and so forth) would ALWAYS have to expend 1000s of fruitless trials crashing the rocket into the moon. It's conceivable that a system could know to develop an internal model of celestial mechanics and use it as a kind of staging area to plan trajectories.
I think there's a danger of questionable philosophy of mind assertions creeping into the discussion here (I've already read several poor or irrelevant expositions of Searle's Chinese Room in the comments). The high-level planning, and "true understanding" stuff sounds very much like what was debated for the last 25 years in philosophy of mind circles, under the rubric of "systematicity" in connectionist computational theories of mind. While I don't want to attempt a single-sentence exposition of this complicated debate, I will say that the requirement for "real understanding" (read systematicity) in AI systems, beyond mechanistic manipulation of tokens, is one that has been often criticised as ill-posed and potentially lacking even in human thought; leading to many movements of the goalposts vis-à-vis what "real understanding" actually is.
It's not clear to me that "real understanding" is not, or at least cannot be legitimately conceptualized as, some kind of geometric transformation from inputs to outputs - not least because vector spaces and their morphisms are pretty general mathematical objects.
EDIT: a word
Re: The Limitations of Deep Learning
#263Earlier quoted context omitted.
I've occasionally found that SVM's work great for one shot learning if you have good features and nicely labelled dataset. CNN's are really good at extracting features. Once you've extracted features that are generic, using an SVM as the last layer to train while keeping the CNN parameters intact yields great accuracy. I think that's where we are really headed. A combination of deep learning, boosted trees, svm, evol…
Wow, I had never considered superintelligence that wasn't at least at some level modeled after the human brain. That is crazy to think about. We could be at the very low end of the spectrum of intelligence I guess.
--Accelerando
Re: The Limitations of Deep Learning
#264Earlier quoted context omitted.
How do you know your brain's not minimizing a loss function?
For the analogy to hold, it's more of a question of whether or not ML algorithms operate in the same way as the brain. Right now, ML models use algorithms from continuous optimization that require certain structure. Namely, we require a Hilbert space, so that we can define things like derivatives and gradients. This puts certain requirements on the kinds of functions that we can minimize and the kinds of spaces that…
Re: The Limitations of Deep Learning
#265Earlier quoted context omitted.
Much of the programming with ML has moved towards cleaning, extrapolating and generating the data. But this type of programing is - miracles- bugfree. We never hear of data-conversion gone wrong, data corrupted or data-mining withou conclusive results here. Obviously such bugs lack the glamour of security bugs.
It's also very difficult to catch these errors. Your trained model just doesn't work as well as it could, but how would you be able to tell?
If validating NN was solved, Darpa had some millions less and alot of plc programming and robotics would be done for.
Basically its validating for every, decision treshold (formerly know as if-else/switch-case) the outcome, in combination with all other decision thresholds. n!.
Maybe one would have a easier time for validating that the NN does not fullfill a certain outcome, by reversing it like a sock, filling the undesired outcome into it, and watch wether a valid input variable appears.
Re: The Limitations of Deep Learning
#266This article is a bit misleading. I believe NNs are a lot like the human brain. But just the lowest level of our brain. What psychologists might call "procedural knowledge". Example: learning to ride a bike. You have no idea how you do it. You can't explain it in words. It requires tons of trial and error. You can give a bike to a physicist that has a perfect deep understanding of the laws of physics. And they won't…
It's a good article in a lot of ways, and provides some warnings that many neural net evangelists should take to heart, but I agree it has some problems. It's a bit unclear whether Fchollet is asserting that (A) Deep Learning has fundamental theoretical limitations on what it can achieve, or rather (B) that we have yet to discover ways of extracting human-like performance from it. Certainly I agree with (B) that the…
Probably the most famous AI critic, Hubert Dreyfus, said "current claims and hopes for progress in models for making computers intelligent are like the belief that someone climbing a tree is making progress toward reaching the moon." But it is progress. Because by climbing a tree I've gained much more than height. I actually did move toward the moon. I've gained the insight that I'm using the right principle.
Re: The Limitations of Deep Learning
#267This article is a bit misleading. I believe NNs are a lot like the human brain. But just the lowest level of our brain. What psychologists might call "procedural knowledge". Example: learning to ride a bike. You have no idea how you do it. You can't explain it in words. It requires tons of trial and error. You can give a bike to a physicist that has a perfect deep understanding of the laws of physics. And they won't…
Re: The Limitations of Deep Learning
#268There is some good information in there and I agree with the limitations he states, but his conclusion is completely made up. "To lift some of these limitations and start competing with human brains, we need to move away from straightforward input-to-output mappings, and on to reasoning and abstraction." There are tens of thousands of scientists and researchers who are studying the brain from every level and we are m…
Re: The Limitations of Deep Learning
#269Earlier quoted context omitted.
> focus a lot of his time on the data itself... from where he intends to collect it? how is it structured? is it reliable? is it "enough"? What's the best books on this subject? I suppose it's a very broad topic and thus more difficult to talk about than a single "neural network" algorithm.
This is the domain of statistics, isn't it?
From what I've seen, statistics addresses these questions better than CS-taught ML does. CS-based ML is no different from algorithm analysis; it suffers from sensitivity to limits inherent in the data. But ML courses often don't address these limits very rigorously. Yet knowing those limits is all important when effectively mining information at a professional level.
If you can't tell the decision maker what you know and what you don't, your inference/prediction really isn't useful. From what I've seen, statistics addresses this best.
Re: The Limitations of Deep Learning
#270Earlier quoted context omitted.
>Didn't happen, ...yet. See my comment here: https://news.ycombinator.com/item?id=14770230
"Never" is a strong prediction. But yes, ANNs have nothing in common with BNNs (biological ... :-)) at all, other than taking them as a very rough abstraction for teaching the basic intuition of the chained up tensor transformations. The hard thing is to predict the when, or even if, of AI. If it will happen, it will be a sudden, light-switch like moment. I don't think AI can happen gradually. At least the first arti…
But our own intelligence happened gradually.