Great article, thanks.

Another place where Carl was wrong, and many others, has been the estimate of the number of 'computers' in your brain (actually nervous system).

Generally speaking the number comes out like 200 billion. People don't realize how small neurons are and how hard it is to study them. I call the computation units "Psi" functions (essentially signal detection function) and there are many different types. We know that. Some estimates come in the hundreds of types, but I think there are thousands. We only have a good idea about how a handful of the types compute their signal detection function.

As one example where we understand the signal detection function and the number: Rods in the human eyeball. There are about 91Million in each eye, or 160Million in both eyes. And they all work more or less the same way (again, I suspect there is more than one type of rod, but that is for another day).

Here is how the brain computes. It take a very large number of these compute engines at work every waking second in the neorcortex. We get estimates of on the order of 90million neocortical neurons with perhaps 3000 such functions associated with each, on a sentence as simple as "I have a dog."

This ain't your dad's computer.

And all you physicists out there, remember. The reality you know is only the reality the thing between your ears can know. We are getting better at understanding what that is too.

Carnegie Mellon University since 1979 — Cognitive Science, AI, Machine Learning, one of the founding Directors of the Robotics Institute.

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