Slashdot Mirror
Ray Kurzweil Does Not Understand the Brain
jamie writes "There he goes again, making up nonsense and making ridiculous claims that have no relationship to reality. Ray Kurzweil must be able to spin out a good line of bafflegab, because he seems to have the tech media convinced..."
Would be nice if the summary even hinted at what the ridiculous claim actually WAS...
Namely, that we'll be able to reverse engineer the human brain in the next 10 years.
I haven't read the article yet, but Ray Kurtzweil is a technology speculator - like a sci-fi writer except that he doesn't make up a story to go with his ideas and tries harder to convince people they're actually going to happen. He wrote "The age of intelligent machines" and "The age of spiritual machines" where he takes a hard AI stance that computer thought can become indistinguishable from human thought. He is also a proponent of technological singularity.
Generally his ideas aren't taken very seriously by academia in Computer Science, or at least that has been my experience. The philosophy department at my university sometimes enjoyed going over his ideas; but the philosophy department at my university was very fond of pseudoscience.
He actually has one.. And he's a dick, too.
why does the platypus always need explaining?
it is the sole remaining species in the Genus Ornithorhynchus and the Family Ornithorhynchidae. along with the echidnas (do they need explaining, too?) they make up the Order Monotremata, the egg-laying, web-footed, electrolocating mammals. they evolved, just like the rest of us.
if there had only been one remaining species of marsupial, would they need explaining?
The "3 million base pairs are 6 million bits" isn't because each pair has two parts, it's becuase each pair has four possibilities. 3 million digits in base 4 is equivalent to 6 million digits in base 2.
For instance, decimal 15 is "33" in base 4 and is "1111" in base 2. You could think of it as one bit for which basepair is at this point in the chain, and one bit for which orientation it's in.
PZ Myers threw a red herring there. What Kurzweil says is pretty reasonable, he used the total amount of information in the genome to get an upper limit estimate of the amount of library code needed to simulate a brain. I say "library" to differentiate from data, since a lot of our brain information comes from our experiences, i.e. library == instincts.
Actually he's right. The statement is pure bullshit.
Or maybe that's too much. Kurzweil just doesn't understand how Kolmorogrov complexity works.
Let's say the brain as a machine is the output of a process. How complicated is that process? The Kolmorogrov complexity of a string (or whatever) is the minimum size of the data that you have to give to a machine in order to produce the string. E.g. a string of 100 0s is simpler than a string of alternating 0s and 1s and simpler than encoding the first 100 digits of pi. Write code for each of those and you'll see the measure works (and it's actually a lower limit, but it's the closest concept...)
But the crucial point is that the size of this string depends on the kind of machine. The size of the input (program) for a Turing machine is very different than that for an actual computer.
So, yes. 800MB of code. But that's not the library code. The library that interprets that program is the egg that grows those 800MB of data into a human, together with all the laws of physics and chemistry involved in the process.
Take all the chromosomes encoding a whole human genome and drop it into a test tube of distilled water. Does it grow a brain? What if you put it into a chicken egg. What grows out? Putting those 800 MB into a computer doesn't do anything if you don't provide the equivalent of the egg. The bootstrap structure and the underlying architecture are as important as the code in understanding the whole system.
Myers is right. In order to understand the human brain directly from the genes you have to understand all chemistry that interacts with it, all the self replicating machinery provided by the mother and simulate that at a molecular level.
So the upper bound is NOT 800 MB. It's 800 MB plus the size of a codebase good enough to simulate every interaction at an atomic level plus a full 3D scan at an atomic level of the egg provided by the mother. Or simplified models of all those things, provided by the chemists and biologists out there, as Myers points out. (Plus data equivalent to a few years of training like we do with children)
Not saying that simulating the brain is necessarilly that hard, it's just that Kurzweil's pseudo-scientific measurement is just bullshit.
Moore's law, the base of his argument that technology is evolving exponentially is pretty much on schedule. We are now on the Petaflop (10^15) range, with the transistor count following the predicted exponential.
Cost of DNA sequencing, another of his examples, is today at 0.000008(USD) per base pair. Fits the curve.
RAM cost is now at 28000kB/USD, also fitting the curve
GDP per capita also is within schedule (note that the scale is logarithmic), even with the wealth transfer east (which is bound to be limited in time to ten more years give or take)
And, lastly, the core of all atacks on Kurzweil, so is life expectancy on track.
You may still believe these exponentials will hit some kind of ceiling somehow. That might be true. The numbers, however, support Kurzweil's theory. And predicting from the number of times Moore's law depletion was announced in the last twenty years, I'd wager my bets on Kurzweil.
If at first you don't succeed, skydiving is not for you
Test your theory against US data. Infant mortality rate in '80 was 13 per thousand births. In '06 was 6 per thousand births. In a thousand people set, you had seven datapoints that lived zero years (worst scenario case) and now show up as living 80 years (again, worst case scenario). The effect of better infant mortality rates comes down to 80*7/1000 years=7 months (average scenarios produce 5 months). Meanwhile, in the same period, life expectancy went from 74 to 78 years.
Better infant mortality rates explain 14% of the increase in life expectancy. Where does the rest come from? Better car safety? Perhaps, but certainly with lower effect than infant mortality. The rest? Medical technology.
If at first you don't succeed, skydiving is not for you