Systems theory

Systems theory is a transdisciplinary/multiperspectual theory that studies structure and properties of systems in terms of relationships from which new properties of wholes emerge.

File:SystemGestalt.jpg

This gestalt graphic, illustrating a central aspect of systems theory, may be alternatively perceived as a whole or as a group of parts. The "systemness" becomes evident when the gestalt is seen as a singular whole.

It was established as a science by Ludwig von Bertalanffy, Anatol Rapoport, Kenneth E. Boulding, William Ross Ashby, Margaret Mead, Gregory Bateson and others in the 1950s, particularly during discussions at the Macy conferences. Systems theory, in its transdisciplinary role, brings together theoretical principles and concepts from ontology, philosophy of science, physics, biology and engineering. Applications are found in numerous fields including geography, sociology, political science, organizational theory, management, psychotherapy (within family systems therapy) and economics among others.

The terms 'systems theory' and 'cybernetics' have been widely used as synonyms, although some authors use the term cybernetic systems to denote a proper subset of the class of general systems, namely those systems that include feedback loops (See also Cybernetics and Systems Theory).

Overview

TIMELINE

1945-55 General Systems Theory (proposed by Ludwig von Bertalanffy and others)
1948–55 cybernetics (W. Ross Ashby, Norbert Wiener) Mathematical theory of the communication and control of systems through regulatory feedback. Closely related: "control theory"
1956 Ludwig von Bertalanffy, Anatol Rapoport, Ralph Garard, Kenneth Boulding establish Society for the Advancement of General Systems Theory.
1970 catastrophe theory (René Thom, E.C. Zeeman) Branch of mathematics that deals with bifurcations in dynamical systems, classifies phenomena characterized by sudden shifts in behavior arising from small changes in circumstances.
1980 chaos theory (David Ruelle, Edward Lorenz, Mitchell Feigenbaum, Steve Smale, James A. Yorke) Mathematical theory of nonlinear dynamical systems that describes bifurcations, strange attractors, and chaotic motions.
1990 complex adaptive systems (CAS) (John H. Holland, Murray Gell-Mann, Harold Morowitz, W. Brian Arthur, ...) The "new" science of complexity which describes emergence, adaptation and self-organization, all of which are basic system principles, was established mainly by researchers of the Santa Fe Institute (SFI) and is based on agents and computer simulations and includes multi-agent systems (MAS) which have become an important tool to study social and complex systems. The study of complex systems today is often subsumed under the term 'complexity theory'. (see for example Edgar Morin, Stuart Kauffman and Steve Wolfram, passim).

Systems theory was the nomenclature early investigators used to describe organization and interdependence of relationships. The system concept contrasts with the Classical perspective of reductionism which has as its subject a single part in that the emphasis shifts from parts to organization of parts. ^[1] A system is composed of regularly interacting or interrelating groups of activities/parts which, when taken together, form a new whole. In most cases this whole has properties which cannot be found in the constituent elements.

In an online article compiled by the Primer Group at ISSS ^[2], Bela H. Banathy writes in the article titled "Systems Inquiry",

"The systems view is a world-view that is based on the discipline of SYSTEM INQUIRY, Central to systems inquiry is the concept of SYSTEM. In the most general sense, system means a configuration of parts connected and joined together by a web of relationships. The Primer group defines system as a family of relationships among the members acting as a whole. Bertalanffy defined system as "elements in standing relationship."

"The joining and integrating of the web of relationships creates EMERGENT PROPERTIES of the whole. These properties of the whole may not be found in any analysis of the parts. This is the VALUE of systems theory. the WHOLENESS that can't be seen in the parts."

"SYSTEMS INQUIRY is a system itself. As a conceptual system, it has four interrelated and internally consistent aspects acting as a whole: systems PHILOSOPHY, systems THEORY, systems METHODOLOGY and systems APPLICATION. Furthermore, systems inquiry embraces two kinds of disciplined inquiry; its conclusion-orientated inquiry mode PRODUCES systems knowledge, its decision orientated inquiry mode APPLIES systems knowledge to the formulation and selection of systems methods that address real-world situations." [^[3]]

An aspect of systems theory, system dynamics, is a method for understanding the dynamic behavior of complex systems. The basis of the method is the recognition that the structure of any system — the many circular, interlocking, sometimes time-delayed relationships among its components — is often just as important in determining its behavior as the individual components themselves. Examples are chaos theory and social dynamics. It is also claimed that, because there are often properties-of-the-whole which cannot be found among the properties-of-the-elements, in some cases the behavior of the whole cannot be explained in terms of the behavior of the parts. An example is the properties of these letters which when considered together can give rise to meaning which does not exist in the letters by themselves. This further explains the integration of tools, like language, as a more parsimonious process in the human application of easiest path adaptability through interconnected systems.

Systems theory has also been developed within sociology. The most widely cited scholar in this area is Niklas Luhmann (see Luhmann 1994). However, some others, such as the members of Research Committee 51 of the International Sociological Association (which focuses on sociocybernetics), have sought to identify the sociocybernetic feedback loops which, it is argued, primarily control the operation of society. On the basis of research largely conducted in the area of education, Raven (1995) has, for example, argued that it is these sociocybernetic processes which consistently undermine well intentioned public action and are currently heading our species, at an exponentailly increasing rate, toward extinction. See sustainability. He suggests that an understanding of these systems processes will allow us to generate the kind of (non "common-sense") targeted interventions that are required for things to be otherwise - ie to halt the destruction of the planet.

The systems framework is also fundamental to organizational theory as organizations are complex dynamic goal-oriented processes. The systems approach to organizations relies heavily upon achieving negative entropy through openness and feedback.

A systemic view on organizations is transdisciplinary and integrative. In other words, it transcends the perspectives of individual disciplines, integrating them on the basis of a common "code", or more exactly, on the basis of the formal apparatus provided by systems theory. The systems approach gives primacy to the interrelationships, not to the elements of the system. It is from these dynamic interrelationships that new properties of the system emerge.

In recent years, the field of systems thinking has been developed to provide techniques for studying systems in holistic ways to supplement more traditional reductionistic methods. In this more recent tradition, systems theory is considered by some as a humanistic extension of the natural sciences.

Significant and far-reaching contributions have been made by Bela H. Banathy who argued, along with the founders of the systems society, that "the benefit of humankind" is the purpose of science. Banathy reports:

"Kenneth Boulding told this story at the occasion when I was privileged to present to him the distinguished scholarship award of the Society of General Systems Research at our 1983 Annual Meeting. The year was 1954. At the Center for Behavioral Sciences at Stanford University, four Center fellows - Bertalanffy (biology), Boulding (economics), Gerard (psychology), and Rapaport (mathematics) -- had a discussion in a meeting room. Another Center fellow walked in and asked: "What is going on here?" Ken answered, "We are angered about the state of the human condition and ask: What can we do -- what can science do -- about improving the human condition?" "Oh!" their visitor said, "That is not my field." "At that meeting the four scientists felt that in the statement of their visitor they heard the statement of the fragmented disciplines that have little concern for doing anything practical about the fate of humanity. So, they asked themselves, "What would happen if science would be redefined by crossing disciplinary boundaries and forged a general theory that would bring us together in the service of humanity?"...Later they went to Berkeley, to the annual meeting of the American Association for the Advancement of Science and established the society for the Advancement of General Systems Theory, (presently known as the International Society for System Sciences (ISSS) [1]). Throughout the years, many of us in the systems movement have continued to ask the question: "How can systems science serve humanity?"

Bela Banathy's last book, Guided Evolution of Society: A System View presented a cultural evolution of concepts and ideas which explores "The Journey from Evolutionary Consciousness to Conscious Evolution." He talks about how biological evolution evolved into a cultural evolution, giving examples of how, when prehistoric man developed a language, his tool making evolved as well. ^[4]

History

In Ludwig von Bertalanffy's foundational text, General System Theory the history of the systems concept is traced back to the 1600s philosophy of G.W. von Leibniz and even Nicholas of Cusa and his Coincidentia Oppositorum. Subjects like complexity, self-organization, connectionism and adaptive systems had already been studied in the 1940s and 1950s, in fields like cybernetics through researchers like Norbert Wiener, William Ross Ashby, John von Neumann and Heinz Von Foerster. Lacking modern tools, they examined complex systems using mathematics, pencil, and paper.

Margaret Mead and Gregory Bateson also had extensive dialogue to bring interdisciplinary principles of systems theory, such as positive and negative feedback, into the social sciences. John von Neumann discovered cellular automata and self-reproducing systems without computers, with only pencil and paper. Aleksandr Lyapunov and Jules Henri Poincaré worked on the foundations of chaos theory without any computer at all.

At the same time Howard T. Odum, the radiation ecologist, recognised that the study of general systems required a language that could depict the energetics and kinetics at any system scale. He developed a general systems, or Universal language, based on the circuit language of electronics to fulfill this role. This language has become known as the Energy Systems Language.

Ilya Prigogine, Prigogine Center for Studies in Statistical Mechanics and Complex Systems, University of Texas at Austin, has studied "far from equilbrium systems" for emergent properties, suggesting that they offer analogues for living systems. The theories of Autopoiesis of Francisco Varela and Humberto Maturana are a further development in this field.

Cybernetics, catastrophe theory, chaos theory and complexity theory have the common goal to explain complex systems that consist of a large number of mutually interacting and interrelated parts in terms of those interactions. Cellular automata (CA), neural networks (NN), artificial intelligence (AI), and artificial life (ALife) are related fields, but they do not try to describe general(universal) complex (singular) systems. The best context to compare the different "C"-Theories about complex systems is historical, which emphasizes different tools and methodologies, from pure mathematics in the beginning to pure computer science now. Since the beginning of chaos theory when Edward Lorenz accidentally discovered a strange attractor with his computer, computers have become an indispensable source of information. One could not imagine the study of complex systems without computers today.

General systems theory as an objective of systemics

Many early systems theorists aimed at finding a general systems theory that could explain all systems in all fields of science. The term goes back to Bertalanffy's book titled General System Theory. von Bertalanffy's objective was to bring together under one heading the organismic science that he had observed in his work as a biologist. His desire was to use the word "system" to describe those principles which are common to systems in general. In GST, he writes: "...there exist models, principles, and laws that apply to generalized systems or their subclasses, irrespective of their particular kind, the nature of their component elements, and the relationships or "forces" between them. It seems legitimate to ask for a theory, not of systems of a more or less special kind, but of universal principles applying to systems in general." (GST p.32)

However, the translation of the German into the English general system theory has "wroth a certain amount of Havoc" writes Ervin Laszlo^[5] in the preface of von Bertalanffy's book Perspectives on General System Theory.. ^[6]

"The original concept of general system theory was Allgemeine Systemtheorie (or Lehre). Now "Theorie" (or Lehre) just as Wissenschaft (translated Scholarship), has a much broader meaning in German than the closest English words "theory" and "science." A Wissenschaft is any organized body of knowledge, including the Geisteswissenschaften (Scholarship of Arts), which would not be considered true sciences in English usage. And Theorie applies to any systematically presented set of concepts, whether they are empirical, axiomatic, or philosophical. (Lehre comes into the same category, but cannot be properly translated. "Teaching," the closest equivalent, sounds dogmatic and off the mark. However, doctrine can be a translation for it as well.)

"Thus when von Bertalanffy spoke of Allgemeine Systemtheorie it was consistent with his view that he was proposing a new perspective, a new way of doing science. It was not directly consistent with an interpretation often put on "general system theory," to wit, that it is a (scientific) "theory of general systems." To criticize it as such is to shoot at straw men. Von Bertalanffy opened up something much broader and of much greater significance than a single theory (which, as we now know, can always be falsified and has usually an ephemeral existence): he created a new paradigm for the development of theories."

Living Systems Theory

The Living Systems Theory of James Grier Miller described by Elaine Parent:

"Living Systems Theory is a general theory about how all living systems "work," about how they maintain themselves and how they develop and change."

"By definition, living systems are open, self-organizing systems that have the special characteristics of life and interact with their environment. This takes place by means of information and material-energy exchanges."

"Living systems can be as simple as a single cell or as complex as a supranational organization (such as the European Economic Community). Regardless of their complexity, they each depend upon the same essential twenty subsystems (or processes) in order to survive and to continue the propagation of their species or types beyond a single generation." [2]

Glossary of Key Terms used by systemists

Because systems language introduces many new terms essential to understanding how a system works, a glossary of many of the significant terms follows:

Adaptive capacity

Adaptive capacity is an important part of the resilience of systems in the face of a perturbation, helping to minimise loss of function in individual human, and collective social and biological systems.

Autopoiesis

The process by which a system regenerates itself through the self-reproduction of its own elements and of the network of interactions that characterize them. An autopoietic system renews, repairs, and replicates or reproduces itself in a flow of matter and energy. Note: from a strictly Maturanian point of view, autopoiesis is an essential property of biological/living systems.

Boundaries

The parametric conditions, often vague, always subjectively stipulated, that delimit and define a system and set it apart from its environment.

Catastrophe

Catastrophe is a mathematical description of a sudden and/or radical change in form, or a similar qualitative change in condition; relates to the theories of Réne Thom.

Closed

A closed system is a state of being isolated from the environment. No system can be completely closed; there are only varying degrees of closure.

Complexity

Complexity is a systemic characteristic that stands for a large number of densely connected parts and multiple levels of embeddedness and entanglement. Not to be confused with complicatedness, which denotes a situation or event that is not easy to understand, regardless of its degree of complexity.

Culture

Culture is the result of individual learning processes that distinguishe one social group of higher animals from another. In humans culture is the set of products and activities through which humans express themselves and become aware of themselves and the world around them. [See cognitive map.]

Development

Development is the process of liberating a system from its previous set of limiting conditions. It is an amelioration of conditions or quality. [See growth and evolution.]

Dissipative structures

Dissipative structure is a term invented by Ilya Prigogine to describe complex chemical structures undergoing the process of chemical change through the dissipation of entropy into their environment, and the corresponding importation of “negentropy” from their environment. Also known as syntropic systems.

Embeddedness

A state in which one system is nested in another system.

Emergence

Emergence is the appearance of novel characteristics exhibited on the level of the whole ensemble, but not by the components in isolation.

Entanglement

Entanglement is a state in which the manner of being, or form of existence, of one system is inextricably tied to that of another system or set of systems.

Entropy

In thermodynamics, entropy is a measure of energy that is expended in a physical system but does no useful work, and tends to decrease the organizational order of the system.

Environment

Environment is the context within which a system exists. It is composed of all things that are external to the system, and it includes everything that may affect the system, and may be affected by it at any given time.

Evolution

Evolution is a tendency toward greater structural complexity, ecological and/or organizational simplicity, more efficient modes of operation, and greater dynamic harmony. A cosmic process specified by a fundamental universal flow toward ever increasing complexity that manifests itself through particular events and sequences of events that are not limited to the domain of biological phenomenon, but extend to include all aspects of change in open dynamic systems with a throughput of information and energy. In other words, evolution relates to the formation of stars from atoms, of Homo sapiens from the anthropoid apes, and the formation of complex societies from rudimentary social systems.

Evolutionary Development

A form of sustainable development concerned with the study of human change in an evolutionary context.

Evolutionary Leadership

The form of leadership required for successful sustainability management in an evolutionary context.

Evolutionary Learning

A community that strives toward sustainable pathways for Community (ELC) evolutionary development, in synergistic interaction with its milieu, through individual and collective processes of empowerment, and evolutionary learning. ELC's do not adapt their environment to their needs, nor do they simply adapt to their environment. Rather, they adapt with their environment in a dynamic of mutually sustaining evolutionary co-creation.

Evolutionary Systems

A form of systems design that responds to the need for a future-Design (ESD) creating design praxis, that embraces not only human interests and life-spans, but those on planetary and evolutionary planes as well. The primary vehicle for the implementation of ESD is the Evolutionary Learning Community (ELC).

Feedback

Feedback is a process by which information concerning the adequacy of the system, its operation, and its outputs are introduced into the system. Negative feedback tells us that there is a discrepancy between what the system produces and what it should produce. It tells us that we should change something in the system so that we can reduce the deviation from the norms stated in the output model of the system. Positive feedback, on the other hand, tells us that the whole system should change, that we should increase the deviation from the present state, and change the output model.

Feedforward

Feedforward is a process, akin to feedback, that informs current operations with future ideals, and adjusts the output model accordingly.

Function

Denotes actions that are required to be carried out in order to meet systems requirements and attain the purpose(s) of the system.

Functions/structure

Structural functionalism is a systems model that organizes in relational arrangements model systems concepts and principles that present an image of a system in a given moment of time. A metaphor for this is a “still-picture” or “snapshot” of the system.

General System Theory

General Systems Theory is the concepts, principles, and models that are common to all kinds of systems and the isomorphisms between and among various types of systems.

Heterarchy

Heterarchy is an ordering of things in which there is no single peak or leading element, and which element is dominant at a given time depends on the total situation, often used in contrast to hierarchy.

Hierarchy

Hierarchy is a vertical arrangement of entities (systems and their subsystems), usually ordered from the top downwards rather than from the bottom upwards.

Holarchy

Holarchy is a concept invented by Arthur Köestler to describe behavior that is partly a function of individual nature and partly a function of the nature of the embedding system, generally operating in a bottom upwards fashion.

Holism

A non-reductionist descriptive and investigative strategy for generating explanatory principles of whole systems. Attention is focused on the emergent properties of the whole rather than on the reductionist behavior of the isolated parts. The approach typically involves and generates empathetic, experiential, and intuitive understanding, not merely analytic understanding, since by the definition of the approach, these forms are not truly separable (as nothing is).

Hologram

A hologram is a three-dimensional photograph created by the interference pattern of two laser beams with the result that each discrete aspect of the image contains all the information necessary to reconstruct the entire image so that, in effect, the whole is contained in all the parts.

Holon

A Holon is a whole in itself as well as a part of a larger system.

Human Activity Systems

Designed social systems organized for a purpose, which they attain by carrying out specific functions.

Learning

Learning is a lifelong process that at the core of adaptive capacity. In human terms it involves a) challenges the learner’s perspective and facilitates the expansion of his/her worldview; b) promotes human fulfillment; c) enables the learner to cope with uncertainty and complexity; and d) empowers the learner to creatively shape change and design the future.

Lowerarchy

A specific type of hierarchy involving a ‘bottom up’ arrangement of entities such that the few are influenced by the many.

Model building

A disciplined inquiry by which a conceptual (abstract) representation of a system is constructed or a representation of expected outcomes/output is portrayed.

Open

An open system is a state and characteristics of that state in which a system continuously interacts with its environment. Open systems are those that maintain their state and exhibit the characteristics of openness previously mentioned.

Organizational learning

A process of developing organizational capacity and human capability to articulate and continuously examine the purposes, underlying perspectives and assumptions, and individual and organizational values in view of the (a) performance of the organization, and (b) the changing characteristics and expectations of the environment(s) in which the organization is embedded.

Paradigm

Paradigms are the set of fundamental beliefs, axioms, and assumptions that order and provide coherence to our perception of what is and how it works; a basic world view; also, example cases and metaphors. [See cognitive map.]

Process model

An organized arrangement of systems concepts and principles that portray the behavior of a system through time. Its metaphor is the “motion-picture” of “movie” of the system.

Reductionism

Reductionism is one kind of scientific orientation that seeks to understand phenomena by a) breaking them down into their smallest possible parts: a process known as analytic reductionism, or conversely b) conflating them to a one-dimensional totality: a process known as holistic reductionism.

Relationship

In the most general sense, a relationship is an interaction between the elements of a system. If the elements of the system are things, then the relationship is what those things are doing to each other. This interaction results in emergent properties which are perceived as the whole such as the wetness of the two gases of water.

Subsystem

A major component of a system. It is made up of two or more interacting and interdependent components. Subsystems of a system interact in order to attain their own purpose(s) and the purpose(s) of the system in which they are embedded.

Suprasystem

The entity that is composed of a number of component systems organized in interacting relationships in order to serve their embedding suprasystem.

Sustainable Development

Sustainable development is a process of human development (individual, societal, or global) that can be said to be socially and ecologically sustainable if it involves an adaptive strategy that ensures the evolutionary maintenance of an increasingly robust and supportive environment. Such a process enhances the possibility that human and other life will flourish in this planet indefinitely.

Sustainability

Sustainability is the ability of a system to maintain itself with no loss of function for extended periods of time. In human terms it is the creative and responsible stewardship of resources — human, Management natural, and financial — to generate stakeholder value while contributing to the well-being of current and future generations of all beings.

Synchrony

Also synchronicity. In engineering; concurrence of periods and/or phases; simultaneity of events or motions: contemporaneous occurrences. In evolutionary systems thinking; a fortunate coincidence of phenomenon and/or of events.

Synergy

Also system. Synergy is the process by which a system generates emergent properties resulting in the condition in which a system may be considered more than the sum of its parts, and equal to the sum of its parts plus their relationships. This resulting condition can be said to be one of synergy.

Syntony

In evolutionary systems thinking; evolutionary consonance; the occurrence and persistence of an evolutionarily tuned dynamic regime. Conscious intention aligned with evolutionary purpose; more loosely, the embodiment and manifestation of conscious evolution; a purposeful creative aligning and tuning with the evolutionary flows of one’s milieu. In traditional radio engineering; resonance.

Syntropy

The process of negentropy-importation. A syntropic system is a dissipative structure.

System

A system is a group of interacting components that conserves some identifiable set of relations with the sum of their components plus their relationships (i.e., the system itself) conserving some identifiable set of relationships to other entities (including other systems).

System Domains

Philosophy; Theory; Methodology; Application.

System types

The members of a set of classifications that arrange human activity systems according to how open-closed, mechanistic-systemic, unitary-pluralistic, or restricted-complex they are. Differentiated on the four-fold continua, system types include those that are rigidly controlled, deterministic, purposive, heuristic, and purpose-seeking.

System-environment

A model to examine and define a system in its model context and to organize systems concepts and principles that are relevant to system-environment interactions.

Systematic thinking

Any methodical step-by-step approach that is carried out according to a pre-determined algorithm or a fixed plan.

Systemic thinking

A tendency or natural predisposition to think in terms of systemic relationships without necessarily drawing upon systems concepts, systems principles, or systems models. Some examples of areas that incorporate and foster such thinking include permaculture, feminist studies, ecology, and the I Ching.

Systems approach

A view that perceives phenomena as a system and deals with problem situations and opportunities that emerge by the application of systems thinking.

Systems design

A decision-oriented disciplined inquiry that aims at the construction of a model that is an abstract representation of a future system.

Systems thinking

An internalized manifestation (in the thinking of individuals or social systems) of systems concepts, systems principles, and systems models.

Wholeness

In reference to systems, the condition in which systems are seen to be structurally divisible, but functionally indivisible wholes with emergent properties.

References

2006, John N. Warfield, AN INTRODUCTION TO SYSTEMS SCIENCE, World Scientific [3]
2006, Korotayev A., Malkov A., Khaltourina D. Introduction to Social Macrodynamics: Compact Macromodels of the World System Growth. Moscow: URSS. ISBN 5-484-00414-4 [4].
2004, Charles François, Encyclopedia of Systems and Cybernetics, Introducing the 2nd Volume [5] and further links to the ENCYCLOPEDIA, K G Saur, Munich [6] see also [7]
1999, Charles François, Systemics and Cybernetics in a Historical Perspective
1984, Niklas Luhmann Soziale Systeme. Grundriss einer allgemeinen Theorie, Frankfurt, Suhrkamp.
1979, Daniel Durand La systémique, Presses Universitaires de France
1975, Gerald M. Weinberg An Introduction to General Systems Thinking (1975 ed., Wiley-Interscience) (2001 ed. Dorset House).
1968, Ludwig von Bertalanffy General System Theory: Foundations, Development, Applications New York: George Braziller
1956, Herman Kahn, Techniques of System Analysis, Rand Corporation

External links

Un-annotated external links

^ Laszlo, Ervin.(1996)The Systems View of the World. Hampton Press, NJ. ( ISBN 1-57273-053-6.
^ http://ISSS.org
^ http://projects.isss.org/Main/SystemsInquiry
^ Banathy, Bela H. Guided Evolution of Society; A Systems View. (2000) Kluwer Academic, New York. ISBN 0-306-46382-2
^ http://projects.isss.org/Main/PerspectivesOnGeneralSystemTheory
^ von Bertalanffy, Ludwig, (1974) Perspectives on General System Thoery Edited by Edgar Taschdjian. George Braziller, New York

[1] Laszlo, Ervin.(1996)The Systems View of the World. Hampton Press, NJ. ( ISBN 1-57273-053-6.

[2] ttp://ISSS.org

[3] ttp://projects.isss.org/Main/SystemsInquiry

[4] Banathy, Bela H. Guided Evolution of Society; A Systems View. (2000) Kluwer Academic, New York. ISBN 0-306-46382-2

[5] ttp://projects.isss.org/Main/PerspectivesOnGeneralSystemTheory

[6] von Bertalanffy, Ludwig, (1974) Perspectives on General System Thoery Edited by Edgar Taschdjian. George Braziller, New York

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