Seeing red

[emjay]

In principle any comp system can be built using nothing but nand...so ultimately I'd have to say that if you knew how neurons worked, to an exacting degree...you would be able to build a replica of the system in another architecture, in nand rather than neuron.  Whether or not this theoretical machine would qualify, to you, as a precise model would be up for debate, I imagine.  All of this is only applicable if mind is comp, ofc.  

I use AND to simplify, grossly, when people are stuck on the fundamentals.....when they think that it -can't- be done.  You can zoom in and out with it.  For example, saying that if a nueron was only able to do what an and gate could do..it could yield this and this...or up higher, saying, if two centers of the brain A and B, through vastly complicated multidirectional concurrent processing involving billions of neurons yield state C...that's red apple.

Cool... that'll be a fun little project then, see if I can approximate one using nothing but logic gates And hopefully learn something about circuits in the process. But just two questions: 1. what's so special about NAND gates compared to other logic gates? and 2. Can each gate only accept two inputs or any number?

[bennyboy]

In principle any comp system can be built using nothing but nand...so ultimately I'd have to say that if you knew how neurons worked, to an exacting degree...you would be able to build a replica of the system in another architecture, in nand rather than neuron.  Whether or not this theoretical machine would qualify, to you, as a precise model would be up for debate, I imagine.  All of this is only applicable if mind is comp, ofc.  

I use AND to simplify, grossly, when people are stuck on the fundamentals.....when they think that it -can't- be done.  You can zoom in and out with it.  For example, saying that if a nueron was only able to do what an and gate could do..it could yield this and this...or up higher, saying, if two centers of the brain A and B, through vastly complicated multidirectional concurrent processing involving billions of neurons yield state C...that's red apple.

I don't think, based on how the neurons work, that a simple series of logic tests is a good approximation of brain function.  In fact, I think the complexities of fluid dynamics or quantum mechanics would be more accurate, although the following casts doubt on whether they would be mutually exclusive.

https://en.wikipedia.org/wiki/Chaos_computing

[The Grand Nudger]

1.  It's a universal gate.  Pile them together and you can realize -any gate- in their aggregate...and thus any function of any comp system.  This is an interesting run in for me...but ask yourself what kind of architecture would be well suited to the sorts of growth by repetition inherent to life?  Redundant ones, ofc.  A simple block that can be arranged in every way the system might require.  Nothing fancy, no top down design work to do.  Just repeat ad infinitum (or until you run out of headspace).  I think neurons are the biological equivalent of universal gates architecturally - but in terms of processing power they're probably more like full alus+......

From the point of view of digital electronics, functional completeness means that every possible logic gate can be realized as a network of gates of the types prescribed by the set. In particular, all logic gates can be assembled from either only binary NAND gates, or only binary .

https://en.wikipedia.org/wiki/Functional_completeness

2. Some gates can accept as many inputs as you like hypothetically (some gates are defined by the numbers of inputs and outputs though), and as many as you can cram in the space, practically (the same is true for outputs).  The number of inputs though, can affect the robustness of the system in either way depending on what it's being tasked to do. For example...if you want C to be red apple....and you have A red and B apple. If you add a third input, X water. Your gate will fail to yield C red apple, even if it yields red and apple...because it did not yield water as well. The number of outputs doesn't have that effect, though, and so those are essentially "free" in the context of the red apple problem as it relates to a three input AND gate. You'd want as many outputs as possible to distribute the state to as many parts of the system as might be useful. Bussing, basically......bussing from hell. Full interconnectivity would be the ideal towards which you'd strive..but ultimately, fail at our scale of manufacture. The scale of manufacture that goes into neurons..however, is much finer.

[bennyboy]

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bump

[bennyboy]

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Fucking Google is watching me and fucking with my posts!

[bennyboy]

Cool... that'll be a fun little project then, see if I can approximate one using nothing but logic gates   And hopefully learn something about circuits in the process. But just two questions: 1. what's so special about NAND gates compared to other logic gates? and 2. Can each gate only accept two inputs or any number?

At the risk of ruining part of Rhythm's fun, I can answer that question:

The NAND gate is significant because any boolean function can be implemented by using a combination of NAND gates. This property is called functional completeness.

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My cleverly pre-emptive post was rudely pre-empted by the guy I was trying to pre-empt.  Get a life, Rhythm!

[The Grand Nudger]

No-LIFE 4life!

[emjay]

Based on what I know about neurons, I think the distribution of neurotransmitters in the brain represents at least partly a chaotic system.  Minor vibrations in the skull, the particular timing of the pulse, and almost anything else could affect the trigger timing of an indidual neuron, or possibly a group of neurons.  We often talk about QM unpredictability as adding an essentially random element to all events, but I think the brain is so complex that classical mechanics should make brain function as unpredictable as the weather, especially over long times.

I'd say dreaming is an excellent example.  Maybe you could see the strange and unpredictable content of dreams each night as a series of butterfly effects causing parts of the brain to light up and come into coordination with each other, sometimes in ways that daily sense perceptions would never allow for.

As a general rule, neurotransmitters don't stay 'outside' of neurons that long... they are released into the 'synaptic cleft' - a narrow gap between the axon of the pre-synaptic neuron and the dendrite of the post-synaptic neuron - in order to trigger receptors on the other side. But any that remains in the synaptic cleft - in the extracellular space - is either broken down or recycled by 'reuptake' in normal circumstances. If there's a problem with that process, then there'll be imbalances like you describe, but under normal circumstances it should be pretty ordered. But you're right... neurotransmitters and other substances floating around in the extracellular fluid could have wide scale effects on the whole network, adding yet another level of complexity to it's operation. Unfortunately I don't know enough about such global effectors, but I wouldn't be surprised if 'neurohormones' had exactly this effect, as a way of mobilising the whole network to act in a different way at the level of it's individual neurons. Because neurotransmitters come in different types and cause different reactions in the receiving neurons... for instance at a simple level, excitatory neurons release a different type of neurotransmitter than inhibitory neurons, causing the post-synaptic neuron to react differently at the site of the synapse, producing excitatory current in the first case and inhibitory current in the second. So in a way neurotransmitters allow the type of neuron to be identified at the synaptic level. It's pretty cool really.

As to dreams, I don't know. I think dreams are about consolidating learning... strengthening synaptic connections... but I don't know.

[The Grand Nudger]

Hey, for a darker twist.  How much is hard observation of the brain/mind worth to us?  How deep down the ethical rabbit hole would we go?  

Let me introduce you to HSD (Hallervorden-Spatz Disease).  Now called NBIA-1(neurodegeneration with brain iron accumulation type 1).   A neurological condition described in 1922, by Hallervorden and Spatz.  Brilliant neurologists.  Go read up on it if you want to be terrified.  Relentlessly progressive dementia with an equally nasty full body experience attached.

They would later lend their expertise (and hone it) in nazi germany assisting with the eugenics program and performing human experimentation.  A faustian bargain. I wonder, if we reached a terminus where no further knowledge was being produced...and we still lacked a complete explanation, would we accept defeat ethically and just smile at the mystery of it all or secretly wish for a couple of nazis to do something shitty?

[bennyboy]

Fair enough. My point is really about a kind of butterfly effect. In a sufficiently complex system, the complexities of classical mechanics will lead to unpredictability. So when we start talking about states and binary decisions, and leave out the chaos (especially as a function of time), I'm not sure whether we are still including the elements essential to the system.