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Ask HN: What data structure does our brain use?

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Re: Ask HN: What data structure does our brain use?

#71

Post by gmt2027 »

toadkick wrote: post #45
gmt2027 wrote: post #38

Earlier quoted context omitted.

Actually representing the entire state of the universe sounds rather ambitious. However, the very action of 'imaging' will force the entire system into a consistent state by quantum collapse. The universe will be represented but changed, the original multitude of super-imposed states will be lost. Heisenberg's uncertainty principle implies that some things are just unknowable . However, only the most basic constituen…

This may be a nitpick, but how can something be "fairly deterministic"? Is it possible for there to be degrees of determinism? I would consider determinism to binary, either something is deterministic, or it is not. If a thing cannot be demonstrated to be deterministic 100% of the time, then by it's very definition it is non-deterministic. By that logic, I would actually conclude that the entire universe does in fact…

I was avoiding an absolute statement because macroscopic objects are entirely capable of behaving in unpredictable ways, however the odds against are so high that the chance of this happening is infinitesimal.

Re: Ask HN: What data structure does our brain use?

#72

Post by gbog »

Interesting answers here, but from their diversity it seems to me that we in fact still don't know much about cognitive representations and their physical anchoring in the brain. I once worked in a lab, studying how the brain sees through the eyes, it wasn't close to explain how we know what is what we see.

Re: Ask HN: What data structure does our brain use?

#73

Post by DavidChouinard »

espeed wrote: post #6

The brain most closely resembles a graph. See Marko's post on "Graphs, Brains, and Gremlin" ( http://markorodriguez.com/2011/07/14/graphs-brains-and-greml... ). Sebastian Seung is a leading researcher in the field of neuroscience called connectomics, which studies the wiring of the brain, and he is a professor at MIT's Department of Brain and Cognitive Sciences. He is focused on mapping the connections between each n…

I second the recommendation of Seung's TED talk. A great watch.

Re: Ask HN: What data structure does our brain use?

#74

Post by Dn_Ab »

shasta wrote: post #70
Dn_Ab wrote: post #46

Earlier quoted context omitted.

A correction. A relation is not a function but a function is a relation. A function is a restriction of a relation such that for each thing_a in A and thing_b in B, for a pairing of (thing_a's,thing_b's) by some relation f,each thing_a can only be paired with one thing_b in B.

A relation between X and Y is a function X -> Y -> Bool.

Yes, sorry, you are right. You were talking about representable/modelled by - which I was conflating with Equivalent as Is. A subtle distinction I missed.

Re: Ask HN: What data structure does our brain use?

#75

Post by nopassrecover »

tzs wrote: post #26
nicholas22 wrote: post #3

There are multiple. I suppose long-term memory is a hashtable and working memory is a stack ;)

I think long term memory is more organized than a hash table. I base this on observation of my own brain during a bad LSD trip, where I seemed to be aware of how I was reaching decisions. For example, if I looked at a door and wanted to remember what that door was for, I could "see" a vast 2 or 3 dimensional array of hundreds of doors that I had seen before, arranged so that similar doors were near each other, and th…

I found LSD did not introduce things that weren't present already. Instead, it removed the filters that are necessary on a daily basis for me to get things done, and suddenly I was aware of and appreciating all the things that my subconscious normally sees and dismisses. The most vivid example of this was an awareness of the patterns and textures surrounding us all the time, as well as the relationship between spatial objects (e.g. a sign or a tree stood out as significant, rather than part of the "background").

Re: Ask HN: What data structure does our brain use?

#76

Post by Cushman »

akg0 wrote: post #64
Cushman wrote: post #63

Earlier quoted context omitted.

But Newtonian mechanics doesn't apply 100% of the time, right? It applies most of the time, from your perspective, because most of the sizes, distances and speeds you deal with are very large, short, and slow compared to their relevant universal constants. But there's a very long tail of very small, far, fast things that do concern you, and there, rarely, your "100%" approximation falls down. You say that the "macros…

It's an observation about the universe. Yes, things about the size of his brain appear to to have deterministic behavior, but so do mountains, oceans, moons, planets and stars - which are, needless to say, nowhere near the size of his brain. The appearance of "randomness" at very small scales can be explained as non-determinism, or as a deterministic effect of some property that we haven't yet detected. The point bei…

Sorry, but your brain (~10^-1m) is way, way closer in size to the Sun (~10^9m) than it is to the Planck length (~10^-35m).

Never mind that, though... So you have a general solution to the n-body problem? I'm being facetious, of course. The hardness of the n-body problem isn't necessarily an expression of fundamental randomness rather than technical uncertainty. But one way or another, aren't they both an expression of the same thing?

Modeling an n-body system in the physical universe exactly means modeling every piece of information in the universe. If you don't do that, the unknowns will multiply into significant divergence at some t, however distant. Quantum theory suggests that even if you did have a computer the size of the universe that didn't affect the universe, it is intrinsically impossible to make an accurate prediction.

I can't know where a particle will be in a second, or even if it will exist at all. I can't know if the Earth will be hit by an asteroid in a hundred years. I can't know who will win the Presidential election next year. The more accurately I model these systems, the more their outcome (or rather the outcome of the abstract macro-system of which I become aware) becomes dependent on the few things I don't know-- to the point that simply the act of checking the accuracy of the prediction has an unpredictable effect.

At that point, it seems like splitting hairs to say "Yes, but it's still really deterministic." What "real" are you talking about? Certainly none that I have experience with. But that doesn't matter either, because even granting that:

The universe might be deterministic, and it might be nondeterministic. It's unpredictable. So how does determinism become the default?

Re: Ask HN: What data structure does our brain use?

#79

Post by jQueryIsAwesome »

akg0 wrote: post #65
jQueryIsAwesome wrote: post #58

Earlier quoted context omitted.

The problem is, all the things we don't understand could be labed as non-determined (i.e: quantum particles moving "randomly")

I don't see how. "Not predictable given what I've observed so far" is a long way from "not predictable".

Wierd... because i think those are the same.
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