There are many definitions of cybernetics and many individuals who have influenced the direction of cybernetics. Cybernetics takes as its domain the design or discovery and application of principles of regulation and communication. Cybernetics treats not things but ways of behaving. It does not ask "what is this thing?" but "what does it do?" and "what can it do?" Because numerous systems in the living, social and technological world may be understood in this way, cybernetics cuts across many traditional disciplinary boundaries. The concepts which cyberneticians develop thus form a metadisciplinary language through which we may better understand and modify our world.

Several traditions in cybernetics have existed side by side since its beginning. One is concerned with circular causality, manifest in technological developments--notably in the design of computers and automata--and finds its intellectual expression in theories of computation, regulation and control. Another tradition, which emerged from human and social concerns, emphasizes epistemology--how we come to know-- and explores theories of self-reference to understand such phenomena as autonomy, identity, and purpose. Some cyberneticians seek to create a more humane world, while others seek merely to understand how people and their environment have co-evolved. Some are interested in systems as we observe them, others in systems that do the observing. Some seek to develop methods for modeling the relationships among measurable variables. Others aim to understand the dialogue that occurs between models or theories and social systems. Early work sought to define and apply principles by which systems may be controlled. More recent work has attempted to understand how systems describe themselves, control themselves, and organize themselves. Despite its short history, cybernetics has developed a concern with a wide range of processes involving people as active organizers, as sharing communicators, and as autonomous, responsible individuals.

My intent in preparing this list was twofold:

1. to demonstrate that one of the distinguishing features of cybernetics might be that it could legitimately have multiple definitions without contradicting itself, and

2. to stimulate dialogue on what the motivations (intentions, desires, etc.) of those who have proposed different definitions might be.

I continue to want cybernetics to be talked about as a dynamic set of ideas, a dynamics that is realized in dialogue among humans. That is, I want the label "cybernetics" to attract people who have an interest in both the subject and practice of conversation, and of creating the "new" out of this form of dynamic interaction, irrespective of whether their interests are in electronics, life, society, or mind, and whether they come from science, art, or politics.

"The study of systems that are open to energy but closed to information and  control-systems that are information tight"

"Cybernetics treats, not things, but ways of behaving. It does not ask, "What is this thing?" but "what does it do?"...It is thus essentially functional and behavioristic... The materiality is irrelevant, and so is the holding or not of the ordinary law of physics"

"deals with all forms of behavior in so far as they are regular, or determinate, or reproducible"

"stands to the real machine-electronic, mechanical, neural, or economic-much as geometry stands to a real object in our terrestrial space"

"offers a method for the scientific treatment of the system in which complexity is outstanding and too important to be ignored"

"the study of form and pattern"

"the biggest bite out of the fruit of the Tree of Knowledge that mankind has taken in the last 2000 years."

"... cybernetics studies the flow of information round a system, and the way in which this information is used by the system as a means of controlling itself: it does this for animate and inanimate systems indifferently. For cybernetics is an interdisciplinary science, owing as much to biology as to physics, as much to the study of the brain as to the study of computers, and owing also a great deal to the formal languages of science for providing tools with which the behaviour of all these systems can be objectively described."

"Probably the first clear insight into the deep nature of control ... was that it is not about pulling levers to produce intended and inexorable results. This notion of control applies only to trivial machines. It never applies to a total system that includes any kind of probabilistic element -- from the weather, to people; from markets, to the political economy. No: the characteristic of a non-trivial system that is under control, is that despite dealing with variables too many to count, too uncertain to express, and too difficult even to understand, something can be done to generate a predictable goal. Wiener found just the word he wanted in the operation of the long ships of ancient Greece. At sea, the long ships battled with rain, wind and tides -- matters in no way predictable. However, if the man operating the rudder kept his eye on a distant lighthouse, he could manipulate the tiller, adjusting continuously in real-time towards the light. This is the function of steersmanship. As far back as Homer, the Greek word for steersman was kubernetes, which transliterates into English as cybernetes."

"The subject to which I have devoted my professional life is cybernetics. I am all too well aware that most people have no more than a hazy idea of what it is all about. I have often been assured that it is about freezing people -- but they were thinking of cryogenics. The more informed realize that it is concerned with systems and their regulation. But even then, there are so many ways in which that notion can be approached."

"The science of cybernetics is not about thermostats or machines; that characterization is a caricature. Cybernetics is about purposiveness, goals, information flows, decision-making control processes and feedback (properly defined) at all levels of living systems."

"At the very least (there is certainly more), cybernetics implies a new philosophy about (1) what we can know, (2) about what it means for something to exist, and (3) about how to get things done. Cybernetics implies that knowledge is to be built up through effective goal-seeking processes, and perhaps not necessarily in uncovering timless, absolute, attributes of things, irrespective of our purposes and needs."

"...[I]t has been variously defined. At one extreme, there is the original definition, 'the science of control and communication in the animal and the machine,' advanced by Norbert Wiener when he adopted the word in 1948 in the book Cybernetics which is the first complete statement of the discipline ... At the other extreme is Louis Couffignal's proposal, put forward as an expansion in 1956, 'La Cybernetique est l'art d'assurer l'efficacite de l'action.' The gap between science and art is filled by a continuum of interpretations. Thus Stafford Beer looks upon cybernetics as the science of proper control within any assembly that is treated as an organic whole. ... Ross Ashby, on the other hand, gives emphasis to abstracting a controllable system from the flux of a real world ..., and he is concerned with the entirely general synthetic operations which can be performed upon the abstract image. He points out that cybernetics is no more restricted to the control of observable assemblies and the abstract systems that correspond to them, than geometry is restricted to describing figures in the Euclidean space which models our environment. ... For my own part, I subscribe to both Ashby's and Beer's view, finding them compatible. Their definitions are both included with Wiener's global dictum."

In broad terms, cybernetics incorporates the following three key ideas: systemic dynamicity; homeostasis around a value; and recursive feedback."