James C. Davies proposed a “rise and drop” hypothesis to explain the origin of revolutions. The present paper attempts to place this in the more general context of analyzing conditions which produce both social movements and revolutions. Three additional temporal hypotheses (“rising expectations,” “relative deprivation,” and “downward mobility”) and one nontemporal hypothesis (“status inconsistency”) are suggested. These five hypotheses are subsumed under the Theory of Cognitive Dissonance. This provides a general social psychological theory of motivation which could account for individual predispositions toward participation in social movements and revolutions. Predictions are made regarding the direction and intensity of such movements.