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Comment by Veedrac | Hacker News Reader

To those who haven't yet read the article, don't bother. Here's a 15-second rendition of the argument to save you the time:

A rat study showed most of a rat brain was used to process information from touch. This does not match ‘function localization’ models of the brain, and might be relevant to brain injury outcomes. There is also debate to what extent, if any, neuron growth happens in adulthood. Therefore we should be suspicious about neuromorphic computation and maybe the brain isn't substrate independent.

No, I'm not skipping a step with ‘therefore’, it really is precisely that abrupt, arbitrary, and poorly-reasoned.

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It's not an in-depth article, but it does make an important point: That we actually understand very little of how our brain really works.

People here on HN used to have a lot of discussions about uploading brains, neuro-preservation, simulating brains, etc. The implicit assumption was always that we already have a pretty solid understanding of how the brain works (it's just a neural network) and we just need to solve a few minor problems (just take a snapshot of all the synapses and we're good to go!).

The truth is, of course, that we have no clue if a neural network even is a good model beyond the most simple circuits (like certain reflexes), and scientists are still scratching the surface.

> we actually understand very little of how our brain really works

That's not exactly "stop-the-presses" kind of news.

I mostly agree, but with two caveats. We do actually know that ‘neural networks’ are poor models for the brain. Backpropagation is unphysical and brains aren't acyclic graphs, for example. What there's uncertainty about is the degree by which they share principles. A glider and an eagle are pretty darn different, and a glider is a terrible model of an eagle, but they do at least utilize the same laws of fluid dynamics to fly. So the question holds for neural networks.

As to neuropreservation, it's important to note that we don't need to understand the brain in order for it to be a good idea. What we care about is whether there will be a future wherein someone does, and whether the technique preserves enough mental structure to allow the brain to be recovered by that somebody.

Yeah, and it fails to acknowledge that there is a long and nuanced body of work in neuroscience concerning the degree of localization vs distribution of function going back at least 100 years (see Karl Lashley, Donald Hebb)

What’s neurotrophic computation and substrate independence?

> Substrate independence

If I recall my terms correctly, substrate independence is the idea that creating intelligence is not dependent on using neurons, but that if you could model the required functionality of neurons in another substrate, an intelligence could also be housed in that substrate.

> Neuromorphic computing Is basically modelling neurological architectures in computers.

Neuro-morphic, having the form of neurons. Recently the buzz refers to circuits that perform neural network operations (the AI kind) using hardware properties directly, storing weights and performing inference or backprop with the computing substrate, which is potentially more efficient or faster than using SRAM and multipliers. It can also refer to hardware directly attempting to model biological neurons, which is more far-field research than the former.

Substrate independence denotes a property being separable from its physical implementation. One could say Alan Turing showed that computation is substrate independent, since many machines all do the same sort of computation. It's often debated whether consciousness is substrate independent, whether a piece of silicon just simulating a human brain will actually have an internal experience of its own thoughts. People who believe in souls, dualism, or panpsychism tend to think it isn't (to different degrees), people who believe in reductionism or emergentism tend to think it is. The authors of this piece go so far as to say the stuff the brain does might not even be reproducible outside of flesh-and-blood, regardless of whether such a reproduction would have internal experience.

> Therefore we should be suspicious about neuromorphic computation and maybe the brain isn't substrate independent.

Wow. So... I'm struggling to find an interpretation of this that doesn't invoke Cartesian dualism.

you could try property dualism or hylomorphism or eliminative materialism

Clearly I have some reading to do. Thanks for the breadcrumbs!

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