Wednesday, January 2, 2013

On Kurzweil's estimates of computer power required for mind uploading

Common transhumanist estimates of computing power necessary for mind uploading strike me as extreme low-ball figures.

To simulate brain correctly would take a lot more computing power than the brain actually can do. Brain is a very complex and messy electronic system, not designed in top down fashion (at least, I am not aware of any transhumanist creationists). The simulation of brain would be more similar to simulation of a weather system than to emulation of a different instruction set. Besides the regular chemical synapses, neurons are coupled: capacitively (electric field), through high speed electrical synapses, through astrocytes, there are voltage-gated ion channels, and a lot, lot more. The neurons have to be simulated compartment by compartment, at small time increments. It may well be that brain has to be simulated as if it was on average 50nm grid, at 10khz time resolution, with about 100 operations per cell step. This would put it at about 1025 FLOPS to simulate human brain. 1025 is nothing to sneer at. This is about a billion times the current best supercomputer (which is at around 1016). And it can still be a low ball estimate. A billion via Moore's law would require shrinkage of current semiconductor process by a factor of 31 thousands. Our current feature size is 22 nanometres, and the silicon lattice spacing is about 0.5 nanometres , so we won't get there by improving current process. The new processes are highly speculative and may not take off for a very, very long time as the current process is also comparatively very cheap in bulk. All the previous computing improvements simultaneously improved performance and decreased the cost; to improve by the factor of a billion, we would need multiple conceptual breakthroughs that would have to compete with existing cheaper alternative right off - and we do not have anything workable in sight. In light of this, I do not expect that Moore's law will continue until mind uploading.


  1. you cant upload a mind, because computers do not have a soul.

    this is why you can throw all the compute power you want at ai and it doesn't really get any better. 1's and 0's dont have a soul, and cannot recreate it.

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  3. random 123, your comment has no soul