Wer sich für die Systemtheorie und im Besonderen für ihre Geschichte interessiert, kommt an Ludwig von Bertalanffy nicht vorbei, auch wenn er heutzutage in systemischen (Lehr-)Büchern eher nur sehr kurz abgehandelt oder gleich in Fußnoten verbannt wird. Es empfiehlt sich daher, ihn im Original zu lesen, da er schon früh viele bedeutsame Aspekte für eine Theorie sozialer und psychischer Systeme geliefert hat (durchaus in kritischer Distanz zu den steuerungsoptimistischen kybernetischen Ansätzen der Gruppe um Norbert Wiener und John von Neumann). Unter diesem Link gibt es einen Zugang zu seiner 1950 verfassten„Outline of General System Theory“, die im„British Journal for the Philosophy of Science“ erschien und in der er den disziplinübergreifenden Anspruch der allgemeinen Systemtheorie begründet. Darin heißt es u.a.:„The central position of the concept of wholeness in biology, psychology, sociology and other sciences is generally acknowledged. What is meant by this concept is indicated by expressions such as ‘system,’ ‘gestalt,’ ‘organism,’ ‘interaction,’ ‘the whole is more than the sum of its parts’ and the like. However, these concepts have often been misused, and they are of a vague and somewhat mystical character. The exact scientist therefore is inclined to look at these conceptions with justified mistrust. Thus it seems necessary to formulate these conceptions in an exact language. General System Theory is a new scientific doctrine of ‘wholeness’—a notion which has been hitherto considered vague, muddled and metaphysical. Considered from the viewpoint of philosophy, General System Theory is to replace that field which is known as ‘theory of categories’ by an exact system of logico-mathematical laws. Those general notions, which as yet have been formulated only in common language, will acquire, by the General System Theory, that unambiguous and exact expression which is possible only in mathematical language“