Concerning the practical issue of repeatability, that's why most fields require a new fact to be independently repeated by several people. At last year Scientif

Concerning the practical issue of repeatability, that's why most fields require a new fact to be independently repeated by several people. At last year Scientific Python Conference, A. Martelli made an interesting point about verifiable software: the best way to know for sure if your software gives the right answer is to have several, different implementation done by different people. He gave the example of the space shuttle, which has several independent systems with a vote in case they don't agree (wikipedia has some information on it:http://en.wikipedia.org/wiki/Space_Shuttle#Flight_systems http://en.wikipedia.org/wiki/Space_Shuttle#Flight_systems).