String theorist Edward Witten says consciousness “will remain a mystery” • Hacker News Board

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#71

Post by JulianMorrison » Mon, Aug 22, 2016, 12:26 PM UTC

collyw wrote: post #47

JulianMorrison wrote: post #32

Earlier quoted context omitted.

If I was to give my unqualified, layperson opinion, I'd say "horse feathers". Consciousness probably isn't "hard" at all. It's a massively parallel brain architecture (which by its widely-spread and slow nature can't accurately self monitor) using theory-of-mind circuitry (developed to handle interpersonal social relations) to model and monitor its own operation. But it feels more sparkly and special to treat it as a…

Do you have any evidence of this, or is it just your pet theory?

Various things read in the past, but nothing I can cite. Feel free to consider it a pet theory.

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#72

Post by JulianMorrison » Mon, Aug 22, 2016, 12:51 PM UTC

TheOtherHobbes wrote: post #68

JulianMorrison wrote: post #42

Earlier quoted context omitted.

You mostly don't self-experience. Mostly you experience what's going on around you, and what you're doing and physically feeling. Mostly, you don't act consciously. But when you direct attention at your own experiencing, or at your own actions in a deliberate way, a subsystem dedicated to that task wakes up and provides you with a homunculus self-model. That would be the 'I'.

And how do you get from a homunculus self-model to the subjective experience of the colour blue? (Or any other colour?) ...Which would be a subjective experience that seems to have curiously objective elements to it, because colours have been shown to correlate with specific sensations and associations across populations. And then there's the much deeper question of the extent to which quantum phenomena need an objec…

As for the quantum stuff, it doesn't need a conscious observer at all. This is why an experimental qbit can decohere in a sealed box no human could possibly peek into. What it needs is one interaction whose result is contingent on state - that's a "measurement" or in unintentionally confusing terminology, an "observation".

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#73

Post by fdej » Mon, Aug 22, 2016, 12:51 PM UTC

Angostura wrote: post #29

This reminds me rather of Roger Penrose's foray into consciousness in The Emperor's New Mind. If you wade your way through it, you'll find the tl;dr is 'consciousness must be a quantum thing because quantum things are mysterious and so is consciousness- oh and look at those microtubules in those neurons - you might get quantum effects in there.' Rather disappointing for such a brilliant man.

Yep. Penrose's argument goes something like this (oversimplified): 1) Turing machines can't solve the halting problem. 2) Humans can solve the halting problem. 3) Therefore, humans can't be Turing machines.

There are two problems with this line of reasoning. The first problem is that 2) is unsubstantiated. A human can see immediately that 15 = 3 x 5, but this doesn't mean that we have a magical ability to factor integers instantly. By the frivolous theorem of arithmetic, almost all natural numbers are very, very, very large. We have some ability to analyze formal systems, but the systems we have managed to understand are very simple in the grand scheme of things. Almost all formal systems are very, very, very complex, and there is no evidence that we can understand them all and/or that our understanding process actually is correct (consistent) when extended indefinitely. Penrose's actual argument is of course more technical, and others have made more precise rebuttals.

The second problem is that the argument does not solve the problem of consciousness. Scott Aaronson put it nicely: "Even if we supposed the brain was solving a hard computational problem, it's not clear why that would bring us any closer to understanding consciousness. If it doesn't feel like anything to be a Turing machine, then why does it feel like something to be a Turing machine with an oracle for the halting problem?"

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#74

Post by zamalek » Mon, Aug 22, 2016, 12:55 PM UTC

tremon wrote: post #58

zamalek wrote: post #19

Earlier quoted context omitted.

Consciousness must exploit growing entropy somehow - otherwise we'd be completely deterministic and consciousness (as an orthogonal consequence of free will) could not exist.

otherwise we'd be completely deterministic Why? The engineering definition of deterministic implies predictable outcomes given a known internal state. Are you suggesting that we're already at the level where we can accurately and fully measure a human brain's internal state?

This is a philosophical discussion because neither the deterministic mind nor the non-deterministic mind can be disproven for exactly the reason that you specify. Scientifically measuring consciousness could be a fool's errand: the very nature of it is subjective.

That does not mean that we cannot discuss the likelihood of each explanation, keeping in mind that both explanations could be incorrect. We have Drake's Equation even though, for all we know, nobody has ever seen an extraterrestrial life-form. We have flight because nature demonstrated flight to us: nature continuously demonstrates the capability to evolve quantum machines (e.g. the nose and various other organic processes[1]).

Finally, the engineering definition of determinism is not the only definition.[2]

[1]: http://www.bbc.com/earth/story/20160715-organisms-might-be-q... [2]: https://en.wikipedia.org/wiki/Deterministic_system_(philosop...

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#75

Post by acqq » Mon, Aug 22, 2016, 1:24 PM UTC

tpm wrote: post #40

A very good book about what we currently (minus 3 years, perhaps) know: https://www.amazon.com/Consciousness-Brain-Deciphering-Codes...

The approach I like is:

https://www.amazon.com/Consciousness-Social-Brain-Michael-Gr...

An article by the same author:

http://www.theatlantic.com/science/archive/2016/03/phlegm-th...

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#76

Post by kordless » Mon, Aug 22, 2016, 3:23 PM UTC

xg15 wrote: post #59

Personal opinion: I can imagine that the reason of how we experience consciousness might be unsolvable, much as the question how the color blue feels is hard to answer objectively. However, I think there are a lot less fuzzy questions that are strongly connected with consciousness that I'm hoping can be find answers for - and that could shed some more light on what consciousness is and what it isn't. Such as: - what…

I would point out some memories are image based and some are not, at least in those who visualize. "What are visualizations?" would be good to add to your list. Visualization appears to be a widely varied ability, yet we know very little about how the ability works, what function it provides to the visualizers and how it can be used to affect change in reality. Some of us have no visualization capabilities. Some have very advanced capabilities. Why?

> The end of science really is the end of the search for final causation.

Causation is everything. It governs from individual choice to the speed of light. Visualizations are internal perceptions that mimic the effect of light on our awareness. Where do those come from and is causality respected in them? Answer that, and you answer the consciousness question.

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#77

Post by MawNicker » Mon, Aug 22, 2016, 3:45 PM UTC

MawNicker wrote: post #56

mettamage wrote: post #26

Earlier quoted context omitted.

Nothing? How do you mean that? Sure, it's not in the vicinity, e.g. machine learning has more to do with statistics and AI but nothing? I'm surprised by that statement, maybe I'm taking it too literal perhaps. I mean, the way neural nets behave in computer vision implies some form of attention. On some benchmarks neurons and deep learning have almost the same biological output (poorly phrased, was from a talk that NG…

Subjective experiences are neurologically evolved and psychologically optimized representations of sensory input. Using only the objective world we ought to be able to infer something about them. Your thought process here is interesting. Color is the optimal subjective encoding of light's frequency and amplitude. We use it to infer material (color) and structure (shading) when we're recognizing objects. The models in…

I regret saying color was the optimal encoding. It's an optimal encoding. Also only for our visual instruments, required operations AND cognitive capacity. Different organisms likely have different sensations. I suspect consciousness is some form of self awareness. Our internal model of space is likely an aspect of this. Many/most organisms lack the neurology for this sort of modeling. They may still have consciousness in some form but I'm afraid to speculate about what it looks like. I'd want to see the Turing Test neural net compared to an ant neural net. That's the most apples to apples analysis I can think of. We can't cheat with awareness of our own subjectivity if we want to understand ourselves. We're never going to be ants. We will never know anything about color. Only how many frequencies and amplitudes of it different humans can detect.

Re: String theorist Edward Witten says consciousness “will remain a mystery”

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Post by agumonkey » Mon, Aug 22, 2016, 5:10 PM UTC

chopin wrote: post #24

agumonkey wrote: post #21

Earlier quoted context omitted.

I'm still stuck at why blue is blue.

And whether your blue is the same as mine...

Exactly. I tend to believe that we're taking "our" consciousness out of mutual observation of our interactions. Kinda like two machines with protocols. To themselves, the world exists because the other responds accordingly.

Re: String theorist Edward Witten says consciousness “will remain a mystery”

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Post by espadrine » Mon, Aug 22, 2016, 5:12 PM UTC

warrenpj wrote: post #61

espadrine wrote: post #35

Earlier quoted context omitted.

> Of course the real explanation of consciousness will be both profound and mundane The expectation of something does not guarantee its existence. Words are created to define the expectation of something unexplained, only to be discarded when the expectation is unmet. Take the word "miasma". At some point in history, a belief was born that all diseases came from gaseous poisons emitted by rot. Then the miasma theory…

> that there is no point of view, just local chemical storage of information. You have just restated the problem of consciousness, except as an assertion that it doesn't exist. The problem of reductionism is that it doesn't stop; just as there aren't really points of view, there aren't really any chemicals, and there isn't really such a thing as (classical, let's say) information. All of these things are "just" emerg…

> You have just restated the problem of consciousness, except as an assertion that it doesn't exist.

Things that don't exist are rarely problematic. But in fairness, I cannot guarantee that there is no consciousness, just as I cannot guarantee that gravity exists — it could be part of a simulation in which I was put since birth, and the real world could have very different laws of physics. Nothing new here, it is Occam's razor.

> it doesn't stop; just as there aren't really points of view, there aren't really any chemicals, and there isn't really such a thing as (classical, let's say) information.

There is such a thing as a point of view. I object to the notion of consciousness solely because of how it is used. Plants have points of view too; jellyfish do too, without the need for a brain. They react intelligently to their environment. Are those conscious? It is clearer to talk about "brains" and "points of view" than it is to talk about "consciousness".

> The explanations which made "aether" and "miasma" obsolete are beautiful, unexpected at the time (in a trivial sense), and of course, not supernatural.

I suppose that's up to each of us to judge. I don't find the idea that throughout my body, millions of tiny unicellular parasites are having a snack, particularly beautiful. Similarly, the idea that there is an invisible energy pulling everything apart always felt supernatural to me.

> if the universe is infinite, isn't it likely that there will be copies of you

The probability is above zero, but given that space is overwhelmingly empty, and given how much information defines my identity (including my average DNA, which is inherited from millions of years of evolution in extremely specific circumstances), it seems unlikely. If there is a copy of me in the universe, the most probable location would be on Earth, extremely close to where I sit.

Re: String theorist Edward Witten says consciousness “will remain a mystery”

#80

Post by visarga » Mon, Aug 22, 2016, 5:15 PM UTC

eutectic wrote: post #20

balazsdavid987 wrote: post #15

Earlier quoted context omitted.

I can't tell whether you are being sarcastic or not. Machine learning has absolutely nothing to do with consciousness. From where people get that connection?

Does human learning have anything to do with consciousness?

I don't think there is something magical in flesh. Consciousness is a process of constructing compact and effective representations of the external world which are necessary in order to learn behavior that maximizes rewards (survival). More sophisticated organisms also develop a model of the world and operate on it by imagination or memory recall, so there is also consciousness of internal mental processes. Such mental processes look like a neural turing machine (read from memory, write to memory, focus on specific parts of sensory field / attention). The mental programs to operate over memory and attention are learned by reinforcement learning. Physical control and operating in the external environment are learned by RL too. The notion of self and language emerge naturally from the need to cooperatively solve problems together with other agents. The teaching signal (reward) is based on the environment and inborn instincts (such as hunger, sleep, defense, sex, cooperation) which are evolutionarily evolved. Part of the perception process is based on unsupervised learning, where raw sense data is encoded in the latent semantic space and then, by a top-down process, is tested by regenerating the original input data. It learns by propagating the error (differences) from the data it generates compared to the original sense data. All these processes have been already implemented, albeit crudely, by machine learning.

Deep Mind has stated that their purpose this year is to build a rat level AI (https://www.youtube.com/watch?v=MAMuNUixKJ8). That would entail rat-level consciousness too.