The Singularity Is Nearer: When We Merge with AI

by Ray Kurzweil

The most commonly discussed worst-case scenario is the potential creation of “gray goo”—self-replicating machines that consume carbon-based matter and turn it into more self-replicating machines.[44] Such a process could lead to a runaway chain reaction, potentially converting the entire biomass of the earth to such machines. Let’s consider how long it might take for the earth’s entire biomass to be destroyed. The available biomass has on the order of 1040 carbon atoms.[45] The carbon atoms within a single replicating nanobot might be on the order of 107.[46] The nanobot therefore would need to create 1033 copies of itself—not all directly, I should stress, but via iterated replication. The nanobots in each “generation” might just create two copies of themselves, or another small number. The astoundingly large numbers come from this process being repeated again and again with the copies and the copies of the copies. So that’s about 110 generations of the nanobots (since 2110 = 1033), or 109 if the nanobots in previous generations stay active.[47] Nanotechnology expert Robert Freitas estimates a replication time of about one hundred seconds, so under ideal conditions the gray goo wipeout time for that much carbon would be around three hours.[48] However, the actual rate of destruction would be much slower, because the world’s biomass is not laid out in a continuous block. The limiting factor would be the actual movement of the front of destruction. Nanobots cannot travel ve...