a process where some form of overall order arises from local interactions between parts of an initially disordered System. The process can be spontaneous when sufficient energy is available, not needing control by any external agent. It is often triggered by seemingly random fluctuations, amplified by positive feedback. The resulting organization is wholly decentralized, distributed over all the components of the system. As such, the organization is typically robust and able to survive or self-repair substantial perturbation.Wikipedia
The emergent organisation of the system enables it to keep up its System Boundary, i.e. survive.
This is equivalent to saying that the system stays in its Attractor states – these are stable configurations of self-organisation. Disruptive changes of system behaviour can be seen as attractor switches.
For a system, so self-organisation can also be understood as Bayesian optimisation of its Implicit Model, i.e. a search algorithm over system states, “looking for” attractors. This can be reframed as “Selection is Bayesian Search of systems components”.