Cybernetics may well be considered the first systemic discipline in Western science. It developed in the early Forties through the circulation of ideas between those studying machines and those studying organisms. Thus it was inherently inter-disciplinary. Both groups of researchers could see similarities in the functioning of the systems they were examining but, of course, each expressed that functioning in the terminology appropriate to their separate disciplines. There was no common language with which those similarities could be discussed. This is what cybernetics was to provide.
The term "cybernetics" was coined (or re-tuned from Plato's usage) by the mathematician Norbert Wiener. It was through his collaborations with the neurophysiologist Arturo Rosenblueth and the engineer Julian Bigelow that the basis of cybernetics was formed. During the Second World War, Wiener was working on guidance systems for anti-aircraft guns. He was working on automated systems that would predict the future trajectory of aircraft by their past trajectory. The servomechanisms involved appeared to exhibit "intelligent" behavior. They also exhibited problems. Recognizing that some of these problems were parallel to those in humans with brain damage, Wiener proposed that the circulation of information required to control an action must form "a closed loop allowing the evaluation of the effects of one's actions and the adaptation of future conduct based on past performances."
This was a statement of what came to be described within cybernetics as "negative feedback." Of course, this term now has a cultural currency that's a good deal skewed from the original. In the cybernetic version the result of an action is fed back into the system to inform its future actions. It doesn't always work that way when you give a person negative feedback, now does it? On the other hand, positive feedback in cybernetics was something to be avoided. This was where a system would respond to the feedback that something was working by increasing the same behavior. The result is that the behavior could escalate and lead to "runaway" which, in some cases, meant explosion. It's like what happens when someone takes a slug of booze, likes it, takes another, likes it, takes another, likes it, on and on until they fall down. Negative feedback would be more like when someone takes a few drinks, notices that their speech is getting a little slurred, and takes this as a signal to stop drinking.
Gregory Bateson was a great enthusiast for cybernetics, having been in on its development in the formative series of conferences sponsored by the Josiah Macy Foundation, together with people like (his ex-wife) Margaret Mead, Warren McCulloch, John von Neumann, and Heinz von Foerster.
Bateson's favorite illustration of a cybernetic system was the thermostat used in domestic heating. The heater is on until such time as the temperature in the room reaches the desired setting, at which point it clicks off, until the temperature drops sufficiently to trigger the heating on again. This is a negative feedback loop, one designed to maintain the temperature that has been set. To use a physiological parallel, the operation of such a heating system is analogous to the process of maintaining blood sugar levels in the human body.
Cybernetics can be considered an example of a pattern approach. It puts a similar emphasis on the relationships between things, rather than the things themselves. As is clear from the examples given, its concern is not with the materials in which the system is operating, but only with how the system operates. It matters not whether the system is wrought in metal and wire or in cells and dendrites. In that regard, cybernetics is a meta-discipline.
Today the term "cybernetics" no longer seems to be current, even while the ideas it was born of are increasingly seen as central to our future. Cybernetics has been subsumed by the ever-expanding monolith that is computer science. The name - or half of it - is likely to live on, though, having been borrowed by the science fiction writer, William Gibson, to create that neologism central to contemporary culture, "cyberspace" (in Gibson's, Neuromancer, a glitzy ride on the wafer thin surfaces of a grungy silicon world).