I believe in evil. It is the property of all those who are certain of truth. Despair and fanaticism are only differing manifestations of evil.

Edward Teller (1908-2003) Hungarian-American theoretical physicist

(Attributed)
    (Source)

Attributed in a personal communication from Judith Shoolery, in Istvan Hargittai, The Martians of Science: Five Physicists Who Changed the Twentieth Century (2006).