Doomsday, nanotechnology, grey goo and the ice-nine scenario

Ice-nine is a fictional substance, invented by Kurt Vonnegut in his novel Cat’s Cradle. In the novel, a fictional Nobel laureate physicist, Felix Hoenikker, creates ice-nine as a secret weapon. Ice-nine takes the form of an alternative structure of water, one solid at normal room temperature. When a single crystal of ice-nine is brought into contact with regular liquid water, a phase transition ensues that causes the molecules of liquid water to arrange themselves into a solid, ice-nine, that is similar to regular ice, but will only melt at temperatures above 114.4 degrees Fahrenheit (45.8 degrees Celsius). The result, of course, is that all the water in the world will freeze and life as we know it would cease to exist.

Vonnegut was using ice-nine as a metaphor for the potential doomsday effect of nuclear weapons; when scientists in the Manhattan Project were first developing the atomic bomb, they first had to do calculations to make sure that the first atomic explosion would not burn so hot as to ignite all the oxygen in the atmosphere (and hence kill us all). Their calculations soon showed, as we all now know, that nuclear weapons have no such ability to cause a runaway effect. But nanobots that feed on carbon and self-replicate will.

The key is the self-replication – like cells in a human body, their internal instructions will include a program for taking materials from the environment (‘food’) and making copies of themselves. Except, well, nanobots will be made of carbon, and have no natural enemies. Hence, if they begin making copies of themselves, they will do so in an exponentially explosive manner, and will presumably take carbon from wherever in the environment they can get it. And guess what – our bodies are made of a great deal of carbon! Hence, the ‘grey goo’ scenario – not long after the first self-replicating carbon-based nanobot is created, we (and everything else made of carbon) will become nothing but a ‘grey goo’.

Hence, in a field called the ethics of ‘existential risk’, a key point of my practical research is to encourage laws that prohibit the development of self-replicating nanotechnology, and closely regulate nanotech in general. Otherwise, self-replicating nanotechnology will be the last invention we humans ever make.