Any difference which makes a difference

"The technical term “information” may be succinctly defined as any difference which makes a difference in some later event. This definition is fundamental for all analysis of cybernetic systems and organization. The definition links such analysis to the rest of science, where the causes of events are commonly not differences but forces, impacts, and the like. The link is classically exemplified by the heat engine, where available energy (i.e., negative entropy) is a function of a difference between two temperatures. In this classical instance, “information” and “negative entropy” overlap." (Bateson, Steps to an Ecology of Mind, p. 386)