Already during his Viennese student days Ludwig von Bertalanffy met the recently graduated Paul A. Weiss in 1924, and they discussed system issues in biology, Weiss, employed at the so called Prater Vivarium,  with an experimental and Bertalanffy with a philosophical background. Five years after Ludwig Bertalanffy's death, the 79-year old Paul Weiss remembered these times: "It was in those days that a sparkling Viennese student, a little more than three years my junior, approached me for a meeting -- Ludwig von Bertalanffy. We met in coffeehouses and 'milked' each other. I soon found that his thinking and mine moved on the same wavelength -- his coming from philosophical speculation, mine from logical evaluation of practical experience. And so it remained for half a century, each of us hewing his separate path according to his predilection. That is, I kept on as the empirical experimental explorer, interpreter, and integrator, for whom the 'system' concept remained simply a silent intellectual guide and helper in the conceptual ordering of experience, while he, more given to extrapolations and broad generalizations, and bent on encompassing the cosmos of human knowledge, made the theory [General System Theory] itself and the applicability of it to many areas of human affairs his prime concern. Does not this confluence here, once again, prove the 'hybrid vigor' of the merger of ideas that, coming from a common source, have converged upon common ground, albeit by separate routes---the one offering a distillate of a life of study of living systems, the other the extensive elaboration of an intuitive philosophical ideology, tested in its pertinence to human evolution?" (Weiss 1977, pp.18-19)

Bertalanffy soon started thinking: if law of gravity applies equally to apples and planets, and if the law of probability applies equally to genetics and life insurance, then laws of biological systems -- such as those governing growth and adaptation of living beings -- might well be applicable to the human psyche, to social institutions, and to the whole global ecosphere. When he was 36 years old, he had formulated the hypothesis that there are natural laws of organization governing systems on all levels of existence, and advocated an interdisciplinary search for such a kind of laws in the domains of the human psyche, social organizations and the global ecosphere.

Bertalanffy also developed his general systems ideas supported by Goethe's view that nature's archetypes are not static ideals but are "never-ending streams of becoming" in accordance with the arguments of the Greek philosopher Heraclitus of Efesus (circa 540-480) "all is flux" because "everything is in flux ... You cannot step into the same river twice, for fresh water is forever flowing towards you". According to Bertalanffy: "Living forms are not in being, they are happening, They are the expression of a perpetual stream of matter and energy which passes through the organism and at the same time constitutes it".

Then, he conceived originally as a related hypothesis his "Allgemeine Systemlehre" while grasping essential aspects of the synergetic character of ecological macro-systems and micro synergetical phenomena in biochemistry and bio-physics. The analogy of growing processes taking place in other human domains led him to seek out the parameters of what could be considered hypothetically wholes or systems, a knowledge that altogether he didn't translated in English as General Systems Teaching, assuming, it is not known precisely why, that "General Systems Theory" was an appropriate term.

Anyhow, GST arose from several evidences: the universe, as it is perceived by humans, is a cosmos because it is not a chaos, it is a symphony because it is not a cacophony; all matter is composed of atoms; all objects are subject to gravity; all life is composed of cells, all species are subject to the same genetic code; humans have been organizing their survival learning to comprehend the order in nature. It has even been commented that GST was the outcome of the drama of a single human mind trying to comprehend the all. It was conceived as a holistic way of thinking and also as an approach to the full spectrum of human problems for making possible "to integrate all aspect of experience".

Bertalanffy in 1937, when he was awarded a Rockefeller Foundation fellowship, lectured at a philosophy seminar (University of Chicago) where he made a first public advocacy of a science to seek and apply laws of systems in general, but it was an unsuccessful presentation. However, a few years later in the 1950s he expressed: "So the idea of general systems theory, after all, was not a personal idiosyncrasy or fancy as I had believed, but rather was one within a group of parallel developments ... Whatever I may have been able to contribute, (there is) plenty for others to do better. And I feel happy that a number of excellent men appear to be willing to do so."

The first publication on system theory appeared in 1949 under the German Title "Zu einer allgemeinen Systemlehre". In 1950 Bertalanffy sent for publication "An Outline of General Systems Theory" after noticing that in physics, biology, psychology and social sciences no longer was acceptable "to explain phenomena by reducing them to an interplay of elementary units which could be investigated independently"

He had certainly recognized that many questions in these domains could no longer be tackled through the traditional reductionism. Instead he realized that it had become evidently necessary to recognize that the basic problems in each scientific domains, were problems about the "relations of organization resulting from a dynamic interaction ... manifesting themselves ... in the whole organism ... governed by dynamic laws".

Even in philosophy he could identify the manifestation of the same general trends towards the explicit recognition of the principles of dynamic wholeness in many systems (theory of categories, doctrine of emergent evolution, organic mechanism and dialectic materialism), which were "diametrically opposed in their scientific, metaphysical and social backgrounds." "This correspondence is the more striking because these development are mutually independent, largely unaware of each other, and based upon totally different facts and contradicting philosophies."

Therefore Bertalanffy thought that General Systems Theory would "be methodologically an important means of controlling and investigating the transfer of principles from one field to another"; that it (GST) would "guard against superficial analogies, which are useless in science and harmful in their practical consequences."

The concept of open system, as it was developed and employed by LvB, in the domain of GST means to think about interaction in every aspect of life and also in every aspect of humankind, which when they are related to the purpose of boundary definition makes necessary to achieve a focus that should be wide enough till including all factors that are relevant. When some essential factors are disregarded or are not recognized the operation of the system risks to be wrongly optimized or suboptimised.

"We believe that the future elaboration of General Systems Theory will prove to be a major step towards the unification of science. It may be destined, in the science of the future, to play a role similar to that of Aristotelian logic in the science of Antiquity ..."