The Better Best System Account, short BBSA is a variation on Lewis’s theory of laws. The difference to the latter is that the BBSA suggests that best system analyses can be executed for any fixed set of properties (instead of perfectly natural properties only). This affords the possibility to launch system analyses separately for the set of biological properties yielding the set of biological laws, chemical properties yielding chemical laws, and so on for the other special sciences.

As such, the BBSA remains silent about possible interrelations between these freestanding sets of laws. In this talk, I explicate an emergence relation between them which preserves the autonomy or novelty of each special science’s laws but also shows their dependence: the autonomy of each level’s generalisations is given because nomicity is conferred to them system intrinsic, their dependence is established via their supervenience on lower level laws.