The sad truth of the matter is that most evil is done by people who never made up their minds to be or do either evil or good.

arendt - the sad truth of the matter is that most evil is done by people who never made up their minds to be or do either evil or good - wist.info quote

Hannah Arendt (1906-1975) German-American philosopher, political theorist
Life of the Mind, Vol. 1 “Thinking,” Part 3, ch. 18 “The two-in-one” (1977)
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Sometimes shortened as: "The sad truth is that most evil is done by people who never make up their minds to be good or evil."

Originally printed as an essay (1977-11-28), "Thinking -- III," The New Yorker (1977-12-05). That version is slightly longer:

The sad truth of the matter is that most evil is done by people who never made up their minds to be either good or bad or to do either good or evil.