RK: Right now… our most complex machines are still on the order of a million times simpler than the human brain. Although we’re making very strong progress in reverse engineering of the human brain — in fact we’ve made some very strong progress even since my book came out two years ago–we still don’t have maps or reverse engineering of 99% of the human brain. We’ll get there because brain scanning, our ability to reverse engineer the human brain, as well as computation, communication and miniaturization are all growing exponentially.
Even if we suppose mind is reducible to brain, I don't think his analysis works. We can only map the brain at scales large enough to be detectable. But matter has an underlying subatomic structure. That pattern can't be mapped. We hit a wall in terms of our inability to detect physical entities below a certain scale.
The basic principle is that bigger things are composed of smaller things. The question is how far down that goes. Where does it bottom out? Does it bottom out? Is matter infinitely divisible? Is there a smallest physical unit?
We can only map what we can scan. To my knowledge, brain scans only map macro brain structures.
You can put slices of a brain under a microscope, but a dead brain doesn't give you all the information you need to map the brain.
High-energy physics would kill the brain. If you put a human inside a collider, what comes out won't be alive.
And even then, we still hit a limit. The part of the brain we perceive is the effect of elementary particles we can't perceive. It's a larger pattern, caused by smaller patterns–like nested Russian dolls. Dolls inside dolls inside dolls.
This is why we can't prove string theory. Even if strings were the ultimate physical constituents, they are too small to detect, because we must use something physical to detect something physical, and what we use is bigger than what we hope to detect.
The structure of the brain we can scan is generated by structures that elude detection. So the resultant map is a very coarse-grained map that misses all the finer details. Like low resolution photography.
That's not to knock brain scanning technology. It contributes to medical treatment. But we can only take it so far.