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> Reinforcement learning: the study of teaching computers how to beat Atari.

This statement says more about the author and her inability to understand RL than about RL itself. RL doesn't fit fast.ai's "AI is easy" narrative therefore it's not worth doing.



There's nothing hard to understand about RL. I'm not sure where you get that idea - if you find it hard, perhaps you just need to look at some different way. Karpathy summarizes the differences with regular supervised learning in his policy gradient post:

> Policy gradients is exactly the same as supervised learning with two minor differences: 1) We don’t have the correct labels yi so as a “fake label” we substitute the action we happened to sample from the policy when it saw xi, and 2) We modulate the loss for each example multiplicatively based on the eventual outcome, since we want to increase the log probability for actions that worked and decrease it for those that didn’t.

(from http://karpathy.github.io/2016/05/31/rl/ )


I find RL hard and no I don't need Karpathy's or fast.ai's dumbed down version of RL. I'm talking about cutting-edge RL like PSRL or RETRACE, not policy gradient or DQN.


Well OK... I don't know why you think those are hard (let alone cutting edge - PSRL isn't new), but it seems important for you to feel like you understand things other people aren't smart enough to, so there's probably not much more I can say.


You can say RL is not hard when you manage to teach all aspects of the SOTA RL algorithm (https://arxiv.org/abs/1707.06887) to your class such that they are able to answer any question about it (not just implement it). Good luck teaching metric spaces to code monkeys.

You guys are doing good work teaching tensorflow and algorithms/models researchers are coming up with, but are slapping those same researchers by disrespecting what they're working on now. Some humility would be wise.


Not sure why the exact details of state of the art research is relevant here. Obviously that definition of RL is dumbing it down, as I'm sure Rachel knows, but the point is simple - teaching a computer to do something specific a human can without explicitly telling it whether something is good or bad, but rather have it learn on its own.

The latest research in RL isn't getting us that much closer to AGI. We can't plop a robot into the real world and tell it to use RL to learn everything.


Before 2012, you also couldn't run a system to classify among 1000 classes. Just because RL isn't there yet, doesn't mean it's not worth doing.

The reason we're discussing hardness of RL is fast.ai's narrative of "you don't need math for AI" and "AI is easy". Sure, implementing and applying AI is easy, and you just need to learn tensorflow, but doing even a modicum of novel research in RL requires a tremendous background in all kinds of math. I appreciate what fast.ai is doing to democratize as much of AI as possible, but that doesn't need to be at odds with other people prioritizing RL research.


fast.ai's narrative is "AI is easy for what you probably want to use it for". There are a ton of awesome applications that are enabled by the level of AI taught in the course. However, Rachel's article is about how AGI is actually really, really hard. So much so that we have no idea how to get there and can't predict when it will happen. So instead of fearmongering about AI, we should instead be encouraging everyone to do awesome new stuff with AI.




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