August 27, 2012
How to life forever
Indefinite Survival through Backup Copies by Anders Sandberg and Stuart Armstrong.
A little technical report for a cute little result: it is possible to have a finite chance to survive an infinite time even if there is a finite chance of getting destroyed per unit of time, if you make backup copies (that are also destroyable) at a high enough rate. The number of backup copies needed only grows logarithmically with time, a surprisingly slow growth.
There are of course complications in adapting this to the real world. Our model can handle time-varying risk, and even some forms of correlated risks. Unfortunately there are risk patterns that are not survivable at all, and the real issue will be common mode risks against the whole backup system.
It is also not a new idea by any means. Mike Perry wrote a paper about it in the 80s: R. Michael Perry, A Mathematical Model of Infinite Survival, Abiolysist Macroscope 3 6-9 and 4 4-9 (1986), and presented it in 1994 at the first Extropy Institute conference. He focuses on the hierarchies of records
David A. Eubanks also had an earlier paper arXiv:0812.0644v1 [q-bio.PE], although his focus seems to be more about looking at the complexity of survival: how does an agent that wants to survive have to think in an unknown universe? (Some blog posts on this)
I think our paper is the first that proves the logarithmic bound, but it is a fairly simple result.