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An Existential Crisis in Neuroscience

m.nautil.us

41–50 of 112 posts

Re: An Existential Crisis in Neuroscience

#41
post #23

"If the human brain were so simple that we could understand it, we would be so simple that we couldn't."

A mind understanding itself may violate the second law, but a few minds understanding one mind should be theoretically possible!

The organization of human thought to achieve that level of understanding might be an issue. From the original article: 'the data footprint of all books ever written come out to less than 100 terabytes, or 0.005 percent of a mouse brain'

Re: An Existential Crisis in Neuroscience

#42

Earlier quoted context omitted.

There are several of these (cognitive architectures) e.g. the ACT-R model[0]. [0] https://en.m.wikipedia.org/wiki/ACT-R

Which ones aren't BS?

I'm not an expert at all. I read the book How Can The Human Mind Occur In The Physical Universe? a few years ago and was basically left with the impression that actually cognitive science is way more advanced than I had realised. I was very struck with the amount of definite results and falsifiable experiments (i.e. "actual science"). I think it's one of those things like global poverty where if you are 30 or older, what you learnt at school, and your whole rule of thumb intuition, is totally wrong.

https://www.oxfordscholarship.com/mobile/view/10.1093/acprof...

Re: An Existential Crisis in Neuroscience

#43
I believe we are at the part where we think how the city works is by mapping it, but you got sewers, pipelines, everything underneath that you haven’t really dug into. There is a lot more inside a neuron that can be mapped. Let’s just say your map isn’t detailed enough

Re: An Existential Crisis in Neuroscience

#44
“ connectomics and whether he thinks we’ll ever have a holistic understanding of the brain. His answer—“No”

As a scientist to say something you don’t fully understand as impossible really pisses me off.

Re: An Existential Crisis in Neuroscience

#45

I'm confused. This article doesn't say anything. It makes no points and has no insight. "There's a lot of data in neuroscience?" Is that the message? An unusual number of Nautilus articles frontpage HN like this one, where there doesn't seem to be any value in the article itself. What is going on?

The message is there are some potential new workflows. Revelation is running out of steam, processing huge quantities of data and relationships between nodes is the new hotness.

Re: An Existential Crisis in Neuroscience

#46
"We don’t understand how their interactions contribute to behavior, perception, or memory. Technology has made it easy for us to gather behemoth datasets, but I’m not sure understanding the brain has kept pace with the size of the datasets."

Exemplifies:

- Data is not information. - Information is not knowledge. - Knowledge is not understanding.

We've not even left the gate of the first tier. Both exciting and intimidating, but mostly humbling. Or should be.

Re: An Existential Crisis in Neuroscience

#47
post #4

What we need is a Newtonian model of the brain. A model that is incomplete and "wrong", but useful and generative. While Newtonian physics may be "wrong", is much easier to learn than quantum physics or relativity, etc. Neuroscience usually focuses on precision details, but doesn't aim to tell big picture stories. There are a few exceptions, however, like Karl Friston's free energy reduction model.

Deep learning is as close to being a "newtonian theory" of the brain as it gets -- deep learning abstracts away a lot of the complexity of neural systems (e.g., a simple artificial neuron vs a highly complex biological one) while maintaining a number of essential characteristics: massively parallel computation, error tolerance, graceful degradation, distributed representations, information is stored in slowly-changing synapses, and, most importantly: a simple, local, and powerful biologically-plausible-if-you-squint-hard-enough learning rule.

The important question to ask is: is the deep learning abstraction any good?

There's a very strong case to be made that the answer is yes: deep learning systems can perform many (of course, not all, at least not yet) tasks that involve perception (computer vision/speech recognition), motor control (the recent openai robot), language understanding (machine translation/BERT/GPT), planning (alphago/dota/the deepmind protein folding), and even some symbolic reasoning (the recent work from facebook on symbolic integration https://ai.facebook.com/blog/using-neural-networks-to-solve-...). Some of these tasks are performed at such a high level that they become commercially useful, and in some cases, surpass "human level".

So here we have a "model family" -- deep learning -- with a set of principles so simple that it can be studied with intense mathematical rigor (for example, https://arxiv.org/pdf/1904.11955.pdf or https://papers.nips.cc/paper/9030-which-algorithmic-choices-...), and that produces many of the behaviors we want out of brains (and not just behavioral: see, e.g., https://arxiv.org/abs/1805.10734: " Interestingly, recent work has shown that deep convolutional neural networks (CNNs) trained on large-scale image recognition tasks can serve as strikingly good models for predicting the responses of neurons in visual cortex to visual stimuli, suggesting that analogies between artificial and biological neural networks may be more than superficial." -- this is just one of many papers that show that even under the hood, trained deep learning systems exhibit many properties of biological neural networks).

These reasons strongly suggest (imho) that deep learning is in fact the newtonian theory of neuroscience. More strongly, no other theory comes remotely close in its simplicity and explanatory power.

Re: An Existential Crisis in Neuroscience

#48

Earlier quoted context omitted.

There are several of these (cognitive architectures) e.g. the ACT-R model[0]. [0] https://en.m.wikipedia.org/wiki/ACT-R

Which ones aren't BS?

None of them as BS, or, put more positively, none of these are complete, but each offers different complexly interlocking partial models, at different levels of description. This is how we understand any complex system. Indeed, this is how we understand anything. Indeed, this is what it means to “understand”, that is, to use models to reason about something. Each of these, and all brain and cognitive science, provides different complexly inTeracting models that we use to reason about the system.

Re: An Existential Crisis in Neuroscience

#49
post #3

If you've seen some of the high resolution videos of neural activity captures from even simple fish, the slightest motor movements activate hundreds of thousands of cells in a chaotic pattern. Neural circuitry is not neatly laid out like a silicon chip, its a forest of inter-connectivity that resists analysis even with extremely detailed visualization and data captures.

I think it’s interesting that people think we’ll be able to make something that does more in a smaller space. As if there was something other than the laws of physics preventing natural selection from testing smaller structures. Or that there’s something (other than the demands of the computation itself) constraining the architectures that were tested through natural selection.

> something (other than the demands of the computation itself) constraining the architectures that were tested through natural selection.

There is. Anything that can't be reached by a small number of genetically small steps that either enhance or at least maintain fitness will never be reached.

Re: An Existential Crisis in Neuroscience

#50
Physicists don't understand gravity...neuroscientists don't understand the main...maybe the universe is a giant brain and the stars are neurons, the big bang was conception and we are bacterial growth. Better than all current theories.
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