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Ray Kurzweil does not understand the brain

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Re: Ray Kurzweil does not understand the brain

#41

Post by yungchin »

mechanical_fish wrote: post #37
yungchin wrote: post #33

Earlier quoted context omitted.

As for the first answer: we all have to learn to deal with roundoff error. That's not by principle an obstacle. The other answer contains an implicit assumption that's not obviously correct: you suggest that complexity only arises when you enumerate every possible dimension of phase space. But physical simulations have been very successful at reproducing complex behaviour from simple rules, without taking into accoun…

No, I'm poking fun at Kurzweil's 2020 deadline, not at you. You appear to have been wise enough not to specify a deadline... As for this statement: physical simulations have been very successful at reproducing complex behaviour from simple rules Absolutely, but it doesn't follow that every complex behavior can be reproduced from simple rules. To overgeneralize from success in one field is the occupational illness of…

Haha, well I guess the fact that for a moment I felt that was condescending mostly says a lot about me ;)

Re: Ray Kurzweil does not understand the brain

#42

Post by kreneskyp »

bh42 wrote: post #13
yungchin wrote: post #10

Earlier quoted context omitted.

Yes, I think that's his point too. But if you believe that the little details of biology emerge from the underlying physics, then maybe you only need to code the fundamental rules and can have all the rest automatically.

I think his point was that we can't code the fundamentals because those require linear time protein folding. And protein folding is one of those hard CS problems.

At this point we don't even have accurate models for most proteins, let alone knowing how to predict what they do.

My current project is a search engine for protein chain geometry. We only have ~20% of the known proteins in our database because the data on the other 80% isn't accurate enough to be useful.

Re: Ray Kurzweil does not understand the brain

#43

Post by TheEzEzz »

cageface wrote: post #32
rsheridan6 wrote: post #16

I don't find these criticisms convincing. We haven't solved the protein folding problem? So solve it. Is there some reason to believe it won't ever be solved? If you had a sufficiently accurate simulation of a cell or organism (which we don't, but we might someday), you could do experiments on it much cheaper and faster than in a lab. I do agree that there's no freakin' way this will be done in ten years, or in the 6…

There is Nobel-prize winning theory that shows that you won't ever truly solve this problem by studying the underlying atomic physics: http://en.wikipedia.org/wiki/Ilya_Prigogine#Dissipative_stru...

I fail to see the connection.

No, a computer simulation can never predict exactly what a physical system will do, even in the case of a single particle, due to quantum uncertainty. But so what? If I took out one of your neurons and replaced it with an identical neuron, that new neuron wouldn't do exactly the same thing, again due to quantum uncertainty; nonetheless, its long term behavior would be essentially identical and you, as a person, would be no different.

That is, neurons and brains are classical objects, essentially immune to the underlying uncertainty they're built on.

Re: Ray Kurzweil does not understand the brain

#44

Post by bld »

mechanical_fish wrote: post #17
arethuza wrote: post #14

Earlier quoted context omitted.

Wow - that "What the Bleep..." does look remarkably bad. The trailer is Poe's Law in action: http://www.youtube.com/watch?v=m7dhztBnpxg I guess you don't want to watch that again? ;-)

It is deadly dangerous for me to watch a clip from that film. It could inspire dozens of hours of rage-filled but closely-argued physics lectures. Given the slightest provocation, I will go all xkcd.com/386 on its ass and my actual career will die of neglect. Now, I need to go calm myself by fixing some bugs before I start to throw things. ;)

Turn that rage into a popular webcomic, then you could start a new career!

Re: Ray Kurzweil does not understand the brain

#46

Post by cageface »

rsheridan6 wrote: post #35
cageface wrote: post #32

Earlier quoted context omitted.

There is Nobel-prize winning theory that shows that you won't ever truly solve this problem by studying the underlying atomic physics: http://en.wikipedia.org/wiki/Ilya_Prigogine#Dissipative_stru...

I'm ignorant of this theory, but reading the link I don't see that it shows that protein folding can't be modeled.

You'd have to read the papers cited below to get the meat of the theory but the gist of it is that you can't model proteins by looking one level down, i.e. by studying only the properties of the atoms that make them up. Proteins have emergent behaviors not entirely predictable from the behaviors of their constituent atoms.

Many still believe in the reductionist idea that a perfect understanding of physics would lead to a perfect understanding of chemistry and then biology. This is not the case.

Re: Ray Kurzweil does not understand the brain

#47

Post by edtechdev »

Hard to take this criticism seriously when it starts off with so many ad hominems.

I haven't read Kurzweil's specific claims, but I'd guess he's claiming we can simulate brain function by 2020. We can already simulate simple organisms and neural networks. You can already accomplish quite a bit of complex emergent behavior with those.

Simulating the entire brain would require an enormous amount of processing (though surely feasible some day, if not 10 years, how about 20), but most likely we'd make some trade-offs and sacrifices and still get a close approximation (like we do with virtually every simulation).

Of course simulating a brain and simulating a human are not the same thing. You can't really avoid having to simulate the entire body and its interactions with the environment.

And of course we wouldn't suddenly "understand" the brain just by simulating it. It would still be the same complex system, it's just we'd be able to inspect it more closely. Such a simulation would at least help us understand a good bit more about the brain's role in our cognition and actions.

And yeah, who knows, maybe in 20 years we could have some kick-ass AI in counterstrike.

Re: Ray Kurzweil does not understand the brain

#48

Post by cageface »

TheEzEzz wrote: post #43
cageface wrote: post #32

Earlier quoted context omitted.

There is Nobel-prize winning theory that shows that you won't ever truly solve this problem by studying the underlying atomic physics: http://en.wikipedia.org/wiki/Ilya_Prigogine#Dissipative_stru...

I fail to see the connection. No, a computer simulation can never predict exactly what a physical system will do, even in the case of a single particle, due to quantum uncertainty. But so what? If I took out one of your neurons and replaced it with an identical neuron, that new neuron wouldn't do exactly the same thing, again due to quantum uncertainty; nonetheless, its long term behavior would be essentially identic…

That is, neurons and brains are classical objects, essentially immune to the underlying uncertainty they're built on.

Absolutely not. Prigogine's work demonstrates that systems far from thermodynamic equilibrium (of which all living systems are an example) are intractably non-deterministic. The issue isn't the underlying quantum uncertainties, it's the macro-uncertainties of the higher-level system.

In other words, you won't predict the behavior a neuron by modeling the underlying physics. You have to learn to model the macro behavior in a statistical way.

Re: Ray Kurzweil does not understand the brain

#49

Post by itg »

rsheridan6 wrote: post #16

I don't find these criticisms convincing. We haven't solved the protein folding problem? So solve it. Is there some reason to believe it won't ever be solved? If you had a sufficiently accurate simulation of a cell or organism (which we don't, but we might someday), you could do experiments on it much cheaper and faster than in a lab. I do agree that there's no freakin' way this will be done in ten years, or in the 6…

>We haven't solved the protein folding problem? So solve it.

It's not a trivial problem. There are lots of bright minds working on this problem. If you understand the difficulty behind it, you wouldn't make such ignorant statements.

Re: Ray Kurzweil does not understand the brain

#50

Post by 10ren »

I'm not so sure about the simulation, but Ray's right that the brain cannot be more complex than the data that specifies it, speaking information-theoretically. A biologist probably wouldn't get this, because he has too much knowledge of how difficult and complex the actual translation is. It's a mathematical idea, like non-constructive proofs, which freak out sensible folk - and rightfully so. (EDIT no offence intended, they freak me out too)

The only other source of information is the non-genomic environment - extra-nucleur DNA like mitochondria, and the womb (which is arguably already specified in the genome, unless mother nature has done a Ken Thompson http://cm.bell-labs.com/who/ken/trust.html at some point.)

But it's weird to claim that 50% of our genome encodes the brain. Really? Perhaps it's just that 50% is required by the brain, much of it being foundational to the whole organism (like standard libraries.)

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