Men, it has been well said, think in herds; it will be seen that they go mad in herds, while they only recover their senses slowly, one by one. - Charles Mackay

"Toda era tem sua loucura peculiar; algum plano, projeto ou fantasia em que mergulha, estimulada pelo amor do ganho, pela necessidade de emoção ou pela simples força da imitação. Se tudo isso falhar, ela ainda assim possui uma loucura, a que é incitada por causas políticas ou religiosas, ou por ambas combinadas." (from "O mundo assombrado pelos demônios: A ciência vista como uma vela no escuro" by Carl Sagan, Charles Mackay)

We find that whole communities suddenly fix their minds upon one object, and go mad in its pursuit; that millions of people become simultaneously impressed with one delusion, and run after it, till their attention is caught by some new folly more captivating than the first.

Three causes especially have excited the discontent of mankind; and, by impelling us to seek remedies for the irremediable, have bewildered us in a maze of madness and error. These are death, toil, and the ignorance of the future..