Ray Kurzweil does not understand the brain

Which would be true if the DNA specification for that particular part of the body was the only part of what specifies the brain. Myers is pointing out that assertion is patently false. The environment of developing creature and the interactions between cell types and their environment (and themselves) is a giant information content multiplier, and the DNA need not explicitly specify any of this information for it to exist and be relevant.

Bringing this to a familiar compsci example; imagine software for creating neural net recognizers. You can look at the source code for a net and say, "This will take N inputs and produce N outputs" You can look at a finished classifier and say, "Ah, I see what this does! It tells the airbags in this car when to deploy!" But that's as far as you can go without the training data that was used to train the classifier. This is a doubly good example because it's often very difficult to determine HOW a complex neural net is doing what it does, but it's fairly easy to explain how to train one to do that task.

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, software, machines, etc. are very loose analogies meant to illustrate a point. Never take these analogies too seriously.

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.

The brain is not a neural network. It is an interconnected colony of living cells of a variety of types, and it has been shown that all types of cells in the brain are involved in cognition.

We are nowhere near anything with the parallelism or information density of the brain. 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. Nature has had billions of years, and it is way ahead of us. There's a nascent field called quantum biology that suggests that the brain may very well be a quantum computer, so maybe quantum computers are the vacuum tubes->ICs scale transition I am speaking of.

I think it's now possible with a big rack of multi-core machines in an MPI cluster to approach the capabilities of a fruit fly's brain.

Cells are not machines. I don't think we have the language to really describe what they are perfectly, but the closest I can come is "stochastic quantum probability field device." A bacterial flagellum is not a "motor," it is a quantum-scale chemo-electro-motive... well... our language breaks down. Like Feynman said, don't tell stories. Just speak literally and then use math.

Actually, come to think of it, there's one engineering analogy that might work for biology. Biology is quantum-scale nanotechnology. Yeah, that's pretty close.

(On a related tangent, I've found that many engineers are sympathetic to intelligent design type arguments against evolution. This is because they try to think about biology like engineers and take these machine analogies literally. It just doesn't work like that.)

http://books.google.com/books?id=lZcSpRJz0dgC&lpg=PP1&#3...

You're conflating two very different concepts of complexity here.

One is the complexity of a static state of information, and the other is the complexity arising from dynamical systems.

As roadnottaken pointed out, fractals are perfect examples of systems that are described by very "simple" formulas, yet contain infinite complexity. It could therefore be said that the simple equation of the Mandelbrot set represents infinite complexity.

However, if you take a particular iteration of the formula, then you can get a finite concept of its complexity, i.e. how many bits it takes to represent the image you're seeing.

So, to say that the "the brain cannot be more complex than the data that specifies it" is true in one sense, but completely useless in another.

To put this into terms of the Mandelbrot, you can gather up all the bits that represents some particular iteration of the Mandelbrot, but that doesn't tell you anything about how it works, or even how to generate the next frame. You need the equation for that.

That's just one place where Ray fails. The second is the lingering question of whether computers in their current state are even capable of "simulating" a brain. It's still not an answered question of what the role of the non-determinism found in Quantum Mechanics plays in the brain and the interactions of various chemicals. It was recently shown that DNA relies on QM entanglement to "hold it together". If it turns out that non-determinism and QM effects play a crucial role in biology (which they almost certainly do), then the very rigid and deterministic system that is the CPU may simply be incapable of simulating a human brain.