We don't have to know everything but he's right that we don't even know enough to get to say "this is an abstraction"; you can't abstract if you don't know what's important. I've worked with spiking nets, biological nets, and DL
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And if for the spiking nets I could carefully say that some properties of in vitro networks are reproduced, I wouldn't say it's an abstraction of the brain for example. For DL it's not even extremely controversial to say that they're not an abstraction of biological networks.
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Just decide on the level of abstraction of your brain model. Hitherto you can go either way. How to decide when your brain model works? – Let's know this before a 1to1 model. Which neural properties do (not) take part in computation, evolution could've exploited anything there?
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It's a goal in neuroscience to build compact mathematical models of individual neurons that accurately reflect how neurons in the brain work. I think Gary's point is we don't know how neurons in the brain work, so it's hard to assess how good the models we have today are.
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And by "we don't know how neurons in the brain work", I don't mean we know nothing. We know lots. But there's also lots we don't know. It's an active area of research.
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you don't have to know everything, but given we can't answer basic questions, eg -what is computational role of dendrites? -why do synapses have 100s of distinct proteins? -why roughly 1000 cell types? -how is short-term memory neurally realized? we can't be confident of much.
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Thanks Gary! I do appreciate you trying to cut through the hype in the field of machine learning- it’s definitely needed.
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I think it depends on the level of analogy you're working on. From a teaching device perspective, I think it's fine to say neural networks behave similarly to biological neurons. But taking that to the level of "neural networks are literally brains" is silly
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"Astonishment ain't what it used to be" -Anonymous
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I was a neuroscientist, and I can assure you it's not unfair criticism. We can say that they're inspired by part of the workings of a class of neural networks, but take care of people who try the analogy too far. Specially people who think they can correct psychology.
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Let's make a list of mechanisms not currently addressed by NNs (note that they don't need to, just to emphasize the differences): * Spiking neurons * Second messengers (maybe LSTM, but even then I doubt the analogy is complete) * Oscillating recurrent circuits (with chaotic dyns)
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