International Encyclopedia of Systems and Cybernetics

D. KATZ and R.L. KAHN state that: "The problem of structure, or the relatedness of parts, can be observed directly in some physical arrangement of things where the larger unit is physically bounded and its subparts are also bounded within the larger structure. But how do we deal with social structures, where physical boundaries in this sense do not exist? It was the genius of F.H. ALLPORT (1962) which contributed the answer, namely that the structure is to be found in an interrelated set of events which return upon themselves to complete and renew a cycle of activities. It is events rather than things which are structured, so that social structure is a dynamic rather than a static concept" (1969, p. 93-4).

The same authors added: "A single cycle of events of a self closing character gives us a simple form of structure. But such single cycles can also combine to give a larger structure of events or an event system. An event system may consist of a circle of smaller cycles or hoops, each one of which makes contact with several others" (Ibid).

In fact, any more or less integrated system is "social". And all structures disclose recurrent functions. They have thus a synchronic and a diachronic aspect.

These already older ideas heralded altogether the organizational closure, autopoiesis and hypercycle concepts.