Tuesday, August 17, 2010

Myers: Kurzweil is a "pseudo-scientific dingbat" who "does not understand" the brain

Biologist and skeptic PZ Myers has ripped into Ray Kurzweil for his recent claim that the human brain will be completely modeled by 2020 (Note: Not that it's particularly important, but Kurzweil did say it'll take two decades at the recent Singularity Summit, not one). In a rather sweeping and insulting article titled, "Ray Kurzweil does not understand the brain," Myers takes the position that the genome cannot possibly serve as an effective blueprint in our efforts to reverse engineer the human brain.

In regards to he claim that the design of the brain is in the genome, he writes,
Kurzweil knows nothing about how the brain works. It's [sic] design is not encoded in the genome: what's in the genome is a collection of molecular tools wrapped up in bits of conditional logic, the regulatory part of the genome, that makes cells responsive to interactions with a complex environment. The brain unfolds during development, by means of essential cell:cell interactions, of which we understand only a tiny fraction. The end result is a brain that is much, much more than simply the sum of the nucleotides that encode a few thousand proteins. He has to simulate all of development from his codebase in order to generate a brain simulator, and he isn't even aware of the magnitude of that problem.

We cannot derive the brain from the protein sequences underlying it; the sequences are insufficient, as well, because the nature of their expression is dependent on the environment and the history of a few hundred billion cells, each plugging along interdependently. We haven't even solved the sequence-to-protein-folding problem, which is an essential first step to executing Kurzweil's clueless algorithm. And we have absolutely no way to calculate in principle all the possible interactions and functions of a single protein with the tens of thousands of other proteins in the cell!
Myers continues:
To simplify it so a computer science guy can get it, Kurzweil has everything completely wrong. The genome is not the program; it's the data. The program is the ontogeny of the organism, which is an emergent property of interactions between the regulatory components of the genome and the environment, which uses that data to build species-specific properties of the organism. He doesn't even comprehend the nature of the problem, and here he is pontificating on magic solutions completely free of facts and reason.
Okay, while I agree that Kurzweil's timeline is ridiculously optimistic (I'm thinking we'll achieve a modeled human brain sometime between 2075 and 2100), Myers's claim that Kurzweil "knows nothing" about the brain is as incorrect as it is disingenuous. Say what you will about Kurzweil, but the man does his homework. While I wouldn't make the claim that he does seminal work in the neurosciences, I will say that his efforts at describing the brain along computationally functionalist terms is important. The way he has described the brain's redundancy and massively repeating arrays is as fascinating as it is revealing.

Moreover, Myers's claim that the human genome cannot inform our efforts at reverse engineering the brain is equally unfair and ridiculous. While I agree that the genome is not the brain, it undeniably contains the information required to construct a brain from scratch. This is irrefutable and Myers can stamp his feet in protest all he wants. We may be unable to properly read this data as yet, or even execute the exact programming required to set the process in motion, but that doesn't mean the problem is intractable. It's still early days. In addition, we have an existing model, the brain, to constantly juxtapose against the data embedded in our DNA (e.g. cognitive mapping).

Again, it just seems excruciatingly intuitive and obvious to think that our best efforts at emulating an entire brain will be informed to a considerable extent by pre-existing data, namely our own DNA and its millions upon millions of years of evolutionary success.

Oh, and Myers: Let's lose the ad hominem.

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