Man and the absolute power

In the Lucifer Effect- a book by Philip Zimbardo – tells of an experiment conducted in the sixties in Standford University. Students were chosen to carry out an experiment in the basement of the university. A prison was recreated and by the flip of a coin 7 students were held hostage while the other 7 students were the prison guards. The guards had absolute power over the victims (except for physical violence) and the experiment was meant to last 2 weeks. Yet, at the end of the 6th day the experiment had to be ceased – victims having nervous breakdowns. The guards, that unleashed their evil, had to go under therapy for years to come. My question then is: is Man, when given absolute power, evil?

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