In his discussion of the general psychological causes of revolution, LeBon draws detailed illustrations of fundamental points from the French Revolution, especially the period from 1789 to 1800. LeBon's treatment of psychological causes is not confined to crowd actions or to the immediate descriptions of violent episodes in revolutions. He draws upon contemporary French clinical psychology to describe the pathological characteristics of the revolutionary leadership in France and explains many of the events of the period as a consequence of their influence.
Although the origin of a revolution may be perfectly rational, we must not forget that the reasons invoked in preparing for it do not influence the crowd until they have been transformed into sentiments
Although in its beginnings a religious or political revolution may very well be supported by rational elements, it is developed only by the aid of mystic and affective elements which are absolutely foreign to reason.