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Artgor t1_irur14y wrote

Right now neural nets are matrix multiplications and activation functions...

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Cogwheel t1_irurt83 wrote

And brains are biochemical reactions and activation action potentials. Not sure what this is trying to say.

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Mysterious_Radish_14 t1_irusp45 wrote

Those are the only things we know about brains, doesn't constitute to 100% of how they work. But we know 100% of the neural network is math that we can 100% comprehend.

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Cogwheel t1_iruw3c8 wrote

O.o in what other manner do brains work besides biochemical??

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mixelydian t1_iruyalp wrote

To our knowledge, the only forces at play are biochemical ones, but that doesn't mean we know all of the biochemical things that go on in a brain that make it work. You could be right in assuming that the brain is a big complicated neural network (if I'm correct in that that's you're assumption), but we simply don't know enough about the brain to confirm that.

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Cogwheel t1_irw5q6u wrote

I'm not sure I understand. We know that the thing between an animal's senses and its behaviors is the nervous system. Just because we don't know all the details of the process doesn't mean the things we do know are wrong.

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mixelydian t1_irw7x58 wrote

I'm not saying the things we know are wrong. Unless we're missing something big, the nervous system is the way that animals process information. I'm just saying that there may be processes in the brain that influence this processing that make it unlike a neural network. For example, at least half of the brain is composed of glial cells which are responsible for upkeep. These cells interact directly with the neurons in multiple ways, such as myelinating axons to increase the speed of action potentials and clearing neurotransmitter molecules from synapses. While we know the basic functions of these cells, it is likely that there are some intricate ways in which they affect the brain's processes. In addition, there are many things that take place in the soma of the neuron that affect whether or not the neuron will have an action potential that we don't fully understand. Finally, neurons regularly move their synapses. This is something which we do not see in neural networks (at least none that I have seen) and is also something which we as yet don't understand. My point is that the brain is a very complex machine that we don't understand enough about to definitively say that it is equivalent in function to a neural network. It might be, but we just don't know.

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Cogwheel t1_irwdfyl wrote

I think the fundamental difference you're pointing out is that a brain's weights change over time, and those changes are influenced by factors beyond the structure and function of the neurons themselves. Maybe this kind of thing is necessary for consciousness, but I don't think it really changes the argument.

We don't normally think of the weights changing over time in a neural net application, but that's exactly what's happening when it goes through training. Perhaps future sentient AIs will have some sort of ongoing feedback/backpropagation during operation.

And because of the space/time duality for computation, we can also imagine implementing these changes over time as just a very large sequence of static elements that differ over space.

So I still don't see any reason this refutes the idea that the operations in the brain can be represented by math we already understand, or that brains are described by biochemical processes.

Edit removed redundant words that could be removed for redundancy

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gravitas_shortage t1_irvh2l2 wrote

We can seriously speculate that the brain uses quantum effects to generate consciousness, for example. It's definitely speculation, but brilliant people like Penrose think it's plausible. There is nothing in neural networks we cannot control or understand if required.

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Cogwheel t1_irw6cmn wrote

This is straight-up quantum mysticism. Quantum mechanics is a rigorous theory that explains the underpinnings of the electro-chemichal processes in everything, including brains.

Why would there be some fundamental force of the universe that only appears in brains?

To the extent any unknown quantum interactions exist, they would have to be negligible.

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gravitas_shortage t1_irw94sv wrote

Who said anything about them only appearing in brains? I'm not a specialist and cannot talk about it, and, forgive me, neither are you. Penrose, and others, are, and seem to think there's enough there to warrant a debate and investigation. Maybe if you get familiar with their argument you can meaningfully agree or disagree, but it's not in my area of expertise, or interest.

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Cogwheel t1_irwa4ld wrote

I don't see how any of this refutes my original point. If there are unknown quantum effects taking place in the brain, they are part of the biochemistry, not separate from it.

And afaik, quantum mechanics is perfectly happy being represented as matrix operations (albeit with shitty space complexity)

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FelisAnarchus t1_irv5bqx wrote

I feel like I could just as truly say that “we can describe neurons with some simple PDEs, and that’s math that we 100% understand,” and I’d be willfully ignorant of just as much.

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impossiblefork t1_iruumdx wrote

Yes, and right now brains are a bunch of nerve cell bundles that may well be basically equivalent to matrix multiplications and activation functions.

But a human brain has 80 billion neurons, each with around 10 000 synapses. That's 8 x 10^14 weights. It's probably noisy and maybe it's equivalent to ANNs that are smaller than this, but even if each synapse was only 1/100 of a bit on average, it's still 8 x 10^11 bits, i.e. 800 GB just for the weights. That's not going to fit on a graphics card.

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