Autocatalytic

referring to something whose occurrence at one point increases the probability that it will occur again at another point. If a property of a system is autocatalytic, then such a system is, so far as that property is concerned, essentially unstable in its absence. (Ashby, 1956, p. 196) Examples: life on the planet Earth, guarantees of civil liberties in one nation among many, a product for which there is a demand. (umpleby )