International Encyclopedia of Systems and Cybernetics

According to R.L. ACKOFF, (as quoted by M.C. JACKSON, 1992, p.145): "About the time of World War II, the "machine age" – associated with the industrial revolution – began to give way to the "systems age". The systems age is characterized by increasingly rapid change, interdependence, and complex purposeful systems. It demands that much greater emphasis be put on learning and adaptation if any kind of stability is to be achieved. This, in turn, requires a radical reorientation of worldview. Machine-age thinking – based upon analysis, reductionism, a search for causeeffects relations and determinism – must be complemented by systems-age thinking, which proceeds by synthesis and expansionism, tries to grasp producer-product relations and admits the possibility of free will and choice".

Nowadays, many more characteristics of systems age are emerging as for example general and special networks development, a clearer view of time dimension in natural and human systems, the discovery of the critical relation of human systems with their specific environments, a better understanding at the same time of the constraints related to autopoiesis and of the concomitant acquisition of individual and group autonomy, etc…