Man in the mass sinks unconsciously to an inferior moral and intellectual level, to that level which is always there, below the threshold of consciousness, ready to break forth as soon as it is activated by the formation of a mass…The change of character brought about by the uprush of collective forces is amazing. A gentle and reasonable being can be transformed into a maniac or a savage beast. One is always inclined to lay the blame on external circumstances, but nothing could explode in us if it had not been already there. As a matter of fact, we are constantly living on the edge of a volcano, and there is, so far as we know, no way of protecting ourselves from a possible outburst that will destroy everybody within reach. It is certainly a good thing to preach reason and common sense, but what if you have a lunatic asylum for an audience or a crowd in a collective frenzy? There is not much difference between them because the madman and the mob are both moved by impersonal, overwhelming forces.
Civilization in Transition
C. G. Jung