There are (at least) four ways of modeling change.
One appeals to the invisible hand: A bunch of actors, each pursuing his own interest, interacts with one another to produce an outcome that none, individually, desires or anticipates. The task is to elaborate the invisible hand processes that generate this surprising outcome-and to assess the outcome's desirability.
Date of Authorship for this Version
Ackerman, Bruce, "Revolution on a Human Scale" (1999). Faculty Scholarship Series. 126.