Ray Kurzweil does not understand the brain • Hacker News Board

Re: Ray Kurzweil does not understand the brain

#141

Post by Confusion » Tue, Aug 17, 2010, 7:02 PM UTC

rsaarelm wrote: post #29

Myers is attacking Kurzweil on the assumption that Kurzweil is actually proposing that the brain's structure should be reverse-engineesed from DNA, which would be intractably hard. Only Kurzweil isn't saying this anywhere. Instead, he seems to be using DNA as a measure for the amount of irreducible complexity that needs to go into a system that will end up with the complexity of a human brain. Basically, we have no i…

  he seems to be using DNA as a measure for the amount of 
  irreducible complexity that needs to go into a system that
  will end up with the complexity of a human brain.

Before an Irreducible Complexity crackpot uses that argument: this complexity is of course not irreducible. It just takes millions of years and the reproduction of the exact mutations and variations in circumstances to reproduce it exactly. A shorter time period, different mutations and circumstances could lead to something akin to this amount of complexity.

Re: Ray Kurzweil does not understand the brain

#142

Post by api » Tue, Aug 17, 2010, 7:04 PM UTC

sliverstorm wrote: post #136

api wrote: post #88

Earlier quoted context omitted.

Not too bad, but sort of like trying to describe an elephant as a bunch of balloons and a water hose glued onto a bail of hay on a table. I also dislike those sorts of analogies because they are loaded with aesthetic value judgements that do not apply. Programming code that looked like that would be ugly. The genetic system is beautiful and elegant.

> The genetic system is beautiful and elegant. Only because you don't have to maintain it

That's what's so beautiful and elegant about it. When "executed" it evolves, so it maintains itself.

Re: Ray Kurzweil does not understand the brain

#143

Post by barmstrong » Tue, Aug 17, 2010, 7:05 PM UTC

jasongullickson wrote: post #74

api wrote: post #65

I'm a life-long programmer who presently works in software, but I studied biology in college... mostly because I wanted to learn about learning by studying how living systems do it. Biological systems are nothing like anything we would ever engineer, and to understand them we must remove our "anthropocentric engineer goggles" and look at them for what they are. Analogies between biological systems and computers, soft…

Getting close would take an advancement in computer technology of the magnitude of the transition from vacuum tubes in individual boxes to a 32nm Core i7. ...so about 35 years? ;)

This is exactly what I was thinking.

Actually, if that last shift took 35 years, the next one of that magnitude will be even faster.

This is Kurtzweil's fundamental insight: exponential growth is faster than people realize. We consistently underestimate it because our brains are pre-disposed to think linearly.

If it takes you 1 year to solve 1% of a problem, your brain feels like you're 99 years away. In reality, you're only 7 doublings from completion.

Re: Ray Kurzweil does not understand the brain

#144

Post by bsaunder » Tue, Aug 17, 2010, 7:06 PM UTC

api wrote: post #114

ewjordan wrote: post #112

Earlier quoted context omitted.

DNA is not a program-- it is a molecule, and one that may very well do things at the quantum level that are biologically important. Sure, but Kurzweil's claim is merely that if DNA can encode everything the brain does with N bits of information, then regardless of how the DNA behaves, we have at least a loose estimate of the level of complexity in the brain. I don't necessarily think that he's right that AI will firs…

"DNA can encode everything the brain does with N bits of information" It doesn't directly encode the structure of the brain. Development is required. "Involved" is a serious weasel word when it comes to the brain, especially when AI is under discussion; everything in your skull is "involved" in cognition, but that doesn't mean it's doing anything particularly important, and it definitely does not mean that every deta…

It doesn't directly encode the structure of the brain. Development is required.

Your Java program doesn't directly execute on the CPU, compilation and interpretation are required.

Re: Ray Kurzweil does not understand the brain

#145

Post by trominos » Tue, Aug 17, 2010, 7:08 PM UTC

This is like saying that the entire universe can be simulated by using a fundamental theory of physics as source code.

It's (to some extent) true, and potentially interesting philosophically -- but completely meaningless from an engineering perspective.

Re: Ray Kurzweil does not understand the brain

#146

Post by api » Tue, Aug 17, 2010, 7:10 PM UTC

bsaunder wrote: post #144

api wrote: post #114

Earlier quoted context omitted.

"DNA can encode everything the brain does with N bits of information" It doesn't directly encode the structure of the brain. Development is required. "Involved" is a serious weasel word when it comes to the brain, especially when AI is under discussion; everything in your skull is "involved" in cognition, but that doesn't mean it's doing anything particularly important, and it definitely does not mean that every deta…

It doesn't directly encode the structure of the brain. Development is required. Your Java program doesn't directly execute on the CPU, compilation and interpretation are required.

Totally different thing. The java program encodes each decision and computation that it performs directly.

Re: Ray Kurzweil does not understand the brain

#147

Post by orborde » Tue, Aug 17, 2010, 7:13 PM UTC

randallsquared wrote: post #130

jberryman wrote: post #113

Earlier quoted context omitted.

relevant to your comment is POSIWID!: the Purpose Of a System Is What It Does

That makes the term "purpose" rather useless, doesn't it?

If you think about it, that's evolutionary theory in a nutshell. Organisms don't evolve due to any desire or goal to change; rather, random processes cause mutations, and traits that happen to result in more copies of themselves being made tend to become more common, and that's it. There is no purpose to the changes; they just are, and "better" ones happen to become more common because they duplicate more.

Re: Ray Kurzweil does not understand the brain

#148

Post by api » Tue, Aug 17, 2010, 7:17 PM UTC

jongraehl wrote: post #133

api wrote: post #65

I'm a life-long programmer who presently works in software, but I studied biology in college... mostly because I wanted to learn about learning by studying how living systems do it. Biological systems are nothing like anything we would ever engineer, and to understand them we must remove our "anthropocentric engineer goggles" and look at them for what they are. Analogies between biological systems and computers, soft…

"the brain may very well be a quantum computer" This is the minority view in neuroscience. > In quantum terms each neuron is an essentially classical object. Consequently quantum noise in the brain is at such a low level that it probably doesn't often alter, except very rarely, the critical mechanistic behaviour of sufficient neurons to cause a decision to be different than we might otherwise expect... —Michael Clive…

You may be right about that, and I don't think the quantum point is essential to what I wrote above.

But... I do tend to sympathize with the minority view here. The problem is that I don't think the majority are looking at the complete system. Yes, the macroscopic activation and conduction behavior of neurons probably can be modeled classically. But that behavior, as well as things like where the axons and dendrites connect, is governed at the meta level by the genetic regulatory networks and metabolic machinery of neurons and their support cells. All that involves at least thousands of genes and a lot of interactions that may very well extend down to the quantum level.

It's a living cell that grows and changes over time, not a simple gate that can be modeled by an equation. Modeling a neuron like that is like modeling a star as a single point source of light because it looks like that from far away. You can model the way stars look through a telescope like that, but that does not accurately describe what a star is.

Re: Ray Kurzweil does not understand the brain

#149

Post by rayval » Tue, Aug 17, 2010, 7:17 PM UTC

akeefer wrote: post #134

ewjordan wrote: post #119

Earlier quoted context omitted.

1) An estimate of complexity is what it is - an estimate of complexity. It's not a claim that the way to achieve AI is to figure out the details of the particular encoding that nature ended up using, so the precise nature of those rules is not something we care about. 2) While it's true that those runtime rules (which we can kind of consider as the "interpreter" for our DNA) are extremely complex, this has almost zer…

I think the article's original point (and mine as well) was that considering the size of the code (i.e. the DNA) as a measure of the complexity of the task is totally disingenuous when you don't have (to use your analogy) the web server, the libraries you're calling, the parser/compiler/linker for the language, the operating system for the server along with its drivers/TCP stack/etc., the processor it runs on, the mo…

Good point. Not only that, but a case can be made that one cannot build such as system as an end stage.

Instead, it appears that ontogeny must recapitulate phylogeny. The system must develop over time as a result of inputs (and the remembered collection of past inputs encoded in the DNA). It would be as if in order to build Twitter with Ruby on Rails, you first had to program a tax calculation application in Cobol on a 1950s mainframe.

Re: Ray Kurzweil does not understand the brain

#150

Post by kragen » Tue, Aug 17, 2010, 7:17 PM UTC

heyadayo wrote: post #107

My programmer's understanding of the argument is this: Even if you could reduce the brain to some sort of bytecode, an interpreter is still necessary to run that bytecode. For instance, a python program might be a few bytes, but the interpreter is still a few megabytes. Yet both are necessary to run the program. Who knows how large a brain bytecode interpreter is going to be, but probably very large.

The interpreter for DNA is a living cell.

There are two problems with this argument:

1. For the interpreter to substantially reduce the size of the DNA needed to encode a program to build an intelligent system, that interpreter needs to be optimized to reduce the complexity of such programs. However, as far as we can tell, ribosomes and protein folding work exactly the same way in nearly all living cells, from snottites to kelp. It isn't plausible to suggest that each Salmonella cell contains hundreds of megabytes of information that's optimized for producing intelligent systems. Even if Salmonella contains hundreds of megabytes of information, it would amount to a proof of creationism if that information were optimized to simplify the expression of brain designs. So the size of the interpreter is irrelevant.

2. DNA is not just interpreted; it's compiled into cells. The DNA of a cell contains a complete program for making every peptide that is necessary to the cell from individual amino acids, and those peptides together construct all the other chemicals from a small number of simple molecules found in the environment. So the source code for the "interpreter", down to the hardware level, is actually already present in the DNA.