The structure of a system the set of relations among its components. The organization of a system is independent of the properties of its components. A machine can be realized by many sets of components and relations among them. Homeostatic systems are systems that keep the values of their variables within a small range of values, i.e. whose organization makes all feedback internal to them. Autopoietic systems turn out to be autonomous, have an identity, are unities, and they compensate external perturbations with internal structural changes.
Living systems are autopoietic systems in the physical space.
An autonomous system cannot be described without describing its observer. Mechanisms of informatin and mechanisms of identity are dual. The cognitive domain of an autonomous system is the domain of interaction that it can enter without loss of closure. General systems theory was born before cybernetics, and cybernetic systems are merely a special case of self-organizing systems. Systems theory studies principles which apply to all systems, properties that apply to any entity qua system.