States and Events

Abstract

Whereas the concepts of state, event, and process belong to ordinary knowledge, those of state variable and state space seem to have sprung up in thermodynamics and statistical mechanics. From these fields they spilled over into others, such as electrical engineering, psychology, biology, automata theory, and systems theory. Systems theorists have of course paid close attention to the technical concepts of state variable and state space, endeavouring to elucidate them in the most general and accurate way possible. However, there is room to doubt whether the usual accounts of these concepts, given in the systems theory literature, are indeed as general as claimed — e.g., whether they make room for continuous systems such as fields, or for quantum-mechanical systems.