Again, in a ship, if a man were at liberty to do what he chose, but were devoid of mind and excellence in navigation (αρετης κυβερνητικης), do you perceive what must happen to him and his fellow sailors? (Plato, Alcibiades, 135A).

Cybernetics is the study of communication and control, typically involving regulatory feedback, in living organisms, in machines and organisations and their combinations, for example, in sociotechnical systems, computer controlled machines such as automata and robots. The term cybernetics stems from the Greek Κυβερνήτης (kybernetes, steersman, governor, pilot, or rudder — the same root as government). It is an earlier but still-used generic term for many of the subject matters that are increasingly subject to specialization under the headings of adaptive systems, artificial intelligence, complex systems, complexity theory, control systems, decision support systems, dynamical systems, information theory, learning organizations, mathematical systems theory, operations research, simulation, and systems engineering.

A more philosophical definition, suggested in 1956 by Louis Couffignal, one of the pioneers of cybernetics, characterizes cybernetics as "the art of ensuring the efficiency of action".