Why Is the Human Brain So Efficient? (2018) • Hacker News Board

Re: Why Is the Human Brain So Efficient? (2018)

#61

Post by rimliu » Fri, Jun 05, 2020, 1:46 PM UTC

LordHeini wrote: post #30

Is it though? I think having a good metric is really hard. For example i can have a neural net running on my smartphone doing recognition tasks. A task the brain is typically good at due to its neural net structure while the computer basically has to simulate the net. But still my smartphone can mark all the faces in a crowd multiple times over in a time i can not recognize even a single person. And that with a camer…

Human eye is very lousy. Only a small patch is capable of some decent resolution. That we actually perceive what we see as something sharp is a compliment to the brain in itself.

Re: Why Is the Human Brain So Efficient? (2018)

#62

Post by checkyoursudo » Fri, Jun 05, 2020, 1:48 PM UTC

kalcode wrote: post #56

ResidentSleeper wrote: post #44

Earlier quoted context omitted.

Whether or not it's comparable depends on the level of distinction you're trying to make. Obviously, CPUs don't think or experience the world (but on the other hand that kind of "feature" seems increasingly likely to be implementable in software, even if our current CPU architectures are rather unsuitable for that goal). However, if we're gonna talk about energy efficiency and computation performance, now that it has…

> now that it has become evident that the brain is merely a kind of a computer I am ignorant in this area. But I keep reading how brains are nothing like computers the more we learn. Your statement seems to suggest otherwise and id love to read about it. Can you drop something where I can start exploring about how the brain has become more evident that it's merely a kind of computer? Thanks!

If you are looking for a book for an introduction, I would suggest Mindware by Andy Clark is pretty reasonable. Pub 2014; ISBN: 9780199828159

Re: Why Is the Human Brain So Efficient? (2018)

#63

Post by coreyp_1 » Fri, Jun 05, 2020, 1:49 PM UTC

shawnz wrote: post #54

coreyp_1 wrote: post #49

Earlier quoted context omitted.

"And indeed CPUs as turing complete, programmable machine are a strict superset of what brains can do." This is a fundamental assertion that I do not believe you can make. The brain cannot simulate a turing machine. It does not have infinite memory, which is a requirement for a turing machine. It can, however, stimulate a linearly bounded automata. It is also not implicitly obvious that a turing machine can simulate…

> The brain cannot simulate a turing machine. It does not have infinite memory, which is a requirement for a turing machine. In practice we call modern computers turing-complete even though they don't have infinite memory. The brain can simulate such a machine. > The brain has no such constraint. It is analog, and therefore infinite in State representation. If this mattered, then it would mean analog computers are mo…

Regarding the Church-Turing thesis, it is exactly that, just a thesis. Again, akin to P vs NP. It seems to hold for most cases, but is not proven.

The reason that it's difficult to apply in regards to the brain is that we don't exactly know how the brain is computing... or if it "computes" at all! To my knowledge, we don't have a model of computation for consciousness, emotion, free will, Etc.

Perhaps these are better classified as emergent Behavior rather than computation, but if that is the case I still don't know of a model explaining what computations or rules give rise to the emergent Behavior.

Perhaps the problem is in our definition of computation and what it means to compute.

We do know that the cardinality of the set of possible computational problems is larger than the cardinality of the set of all possible Turing machines. This is provable by simple diagonalization proofs.

The question, then, is whether or not the computations of the brain fall Within the set of Turing recognizable languages (computational problems). To my knowledge, this has not been shown.

Re: Why Is the Human Brain So Efficient? (2018)

#64

Post by jameshart » Fri, Jun 05, 2020, 1:49 PM UTC

otabdeveloper4 wrote: post #40

The_rationalist wrote: post #23

Earlier quoted context omitted.

Comparing Human Brain with a CPU is misconception. no it is not. Yeah architecturally they are very different and CPU are arguably more programmable / general and less efficient. What does matter is whether CPUs are theoretically able to achieve all the things that a brain can do (and even more) And indeed CPUs as turing complete, programmable machine are a strict superset of what brains can do. The gap between what…

The human brain isn't Turing-complete. Turing completeness implies infinite recursion, which the brain obviously can't do.

This is a silly objection, trivially because obviously no finite physical system - brain or computer or whatever - can be constructed with the storage equivalent of an infinitely long tape. But if you allow for the fact that humans can do things like write things down and share information with other humans and build computers to store information, our information processing capacity is not limited to the set of states we can hold inside the atoms inside our head.

But also, the claim lacks evidence: We’ve never seen a human being yet whose program didn’t eventually halt.

That doesn’t mean the hardware isn’t capable of running a program that never halts, just that we haven’t found such a program yet.

Indeed if you consider human mindware as a whole, given that when humans reproduce they create new copies of the mind running in new bits of hardware... maybe Human minds are infinitely recursive after all?

Re: Why Is the Human Brain So Efficient? (2018)

#65

Post by criddell » Fri, Jun 05, 2020, 1:57 PM UTC

sooheon wrote: post #43

criddell wrote: post #41

Earlier quoted context omitted.

Is there anything analogous to software in biology?

Biology is the ultimate legacy software running on one of the oldest platforms ever developed, the organic compounds. It is literally a giant genetic algorithm to write instructions (DNA) for manufacturing molecular machines (proteins) that interact with each other in an extremely complex graph of relations (protein pathways, i.e. control flow).

That feels more to me like hardware and software in the sense of a Jacquard loom. I suppose it fits though.

I was thinking more about what's going on in the brain. We have all the regions mapped to specific functions with higher and lower level parts. The low level parts seem to be like hard-wired stimulus-response mechanisms. Are the higher level systems the same at a meta level or is there a type of program running on the hardware of the brain?

Re: Why Is the Human Brain So Efficient? (2018)

#66

Post by cmehdy » Fri, Jun 05, 2020, 2:04 PM UTC

The_rationalist wrote: post #23

tegeek wrote: post #15

Earlier quoted context omitted.

Comparing Human Brain with a CPU is misconception. In the past when we didn't have digital computers we used to compare Brain with other machines. And now with a CPU. A Brain from a primitive neuron to higher level is not comparable to any machine at all including the CPU.

Comparing Human Brain with a CPU is misconception. no it is not. Yeah architecturally they are very different and CPU are arguably more programmable / general and less efficient. What does matter is whether CPUs are theoretically able to achieve all the things that a brain can do (and even more) And indeed CPUs as turing complete, programmable machine are a strict superset of what brains can do. The gap between what…

> CPUs as turing complete, programmable machine are a strict superset of what brains can do

In what way can this be proven?

It's very tempting in an era of tech-centered growth to think of computers as the solution to everything, but we are barely even beginning to understand the brain. We know computers fairly well and can talk about them, but how can we make such a claim when we don't know the other thing we're talking about?

In fact, the brain created the computer, didn't it? Therefore, from that standpoint it is arguable that the brain is a superset of the computer. It's not something I really believe in (because my opinion is that you can't really equate things that are of entirely different units, one of which being unknown), but just a "devil's advocate".

Re: Why Is the Human Brain So Efficient? (2018)

#67

Post by supergarfield » Fri, Jun 05, 2020, 2:04 PM UTC

coreyp_1 wrote: post #63

shawnz wrote: post #54

Earlier quoted context omitted.

> The brain cannot simulate a turing machine. It does not have infinite memory, which is a requirement for a turing machine. In practice we call modern computers turing-complete even though they don't have infinite memory. The brain can simulate such a machine. > The brain has no such constraint. It is analog, and therefore infinite in State representation. If this mattered, then it would mean analog computers are mo…

Regarding the Church-Turing thesis, it is exactly that, just a thesis. Again, akin to P vs NP. It seems to hold for most cases, but is not proven. The reason that it's difficult to apply in regards to the brain is that we don't exactly know how the brain is computing... or if it "computes" at all! To my knowledge, we don't have a model of computation for consciousness, emotion, free will, Etc. Perhaps these are bette…

As far as I understand, the prevailing opinion is that the brain is a physical object and that its operation does not involve currently-unknown laws of physics (because we have a good understanding of what happens at the scale of an entire atom or above).

A Turing machine can run a simulation based on such physical laws to any desired level of precision (which is enough, because as mentioned in TFA, processes in the brain aren't individually very precise). This is true because of the nature of these laws, which are mostly just asking you to integrate differential equations. If you accept this, then it should follow that a Turing machine can in fact simulate a brain: just run a physics sim on a brain's initial state.

(I do realize that this is far outside the realm of what's doable today, but it seems to provide a solid justification for why it's conceptually possible).

Re: Why Is the Human Brain So Efficient? (2018)

#68

Post by Someone » Fri, Jun 05, 2020, 2:06 PM UTC

The_rationalist wrote: post #23

tegeek wrote: post #15

Earlier quoted context omitted.

Comparing Human Brain with a CPU is misconception. In the past when we didn't have digital computers we used to compare Brain with other machines. And now with a CPU. A Brain from a primitive neuron to higher level is not comparable to any machine at all including the CPU.

Comparing Human Brain with a CPU is misconception. no it is not. Yeah architecturally they are very different and CPU are arguably more programmable / general and less efficient. What does matter is whether CPUs are theoretically able to achieve all the things that a brain can do (and even more) And indeed CPUs as turing complete, programmable machine are a strict superset of what brains can do. The gap between what…

“programmable machine are a strict superset of what brains can do”

As others already replied, that’s a statement that isn’t universally accepted to be true.

As an example, there’s consciousness. People disagree about whether it exists, whether it’s (fully) ‘in’ the brain, and on whether computers could in theory be conscious.

There are people who answer those questions with yes, yes, and no, and, since we don’t even have a good idea about what consciousness is, one cannot reliably argue that they are wrong (also not that they are right, of course)

Re: Why Is the Human Brain So Efficient? (2018)

#69

Post by kristopolous » Fri, Jun 05, 2020, 2:13 PM UTC

They aren't the same thing. They are different classes of objects, different tasks. This comparison is kind of silly.

I'd hate my computer to have the memory accuracy or the computational accuracy of my brain. I'd hate to have the creativity and inspiration of a computer.

Delete being such a nontrivial operation is probably a good thing for humans. Copy being imperfect probably has something to do with the phenomenon we call imagination. We use computers because they are complementary, not substitutive.

They're just so fundamentally different.

Re: Why Is the Human Brain So Efficient? (2018)

#70

Post by SomeoneFromCA » Fri, Jun 05, 2020, 2:22 PM UTC

sooheon wrote: post #55

SomeoneFromCA wrote: post #51

Earlier quoted context omitted.

This a very simplistic view, based on assumption that the world is discrete. The whole idea of software relies on the concept of digital computer, a discrete machine. The world might indeed be analogous and real numbers might actually exist.

I think the assumption that software may only be digital is the limited one.

Otherwise it becomes a meaningless, all-encompassing term.