A good cause can become bad if we fight for it with means that are indiscriminately murderous. A bad cause can become good if enough people fight for it in a spirit of comradeship and self-sacrifice. In the end it is how you fight, as much as why you fight, that makes your cause good or bad. —Freeman Dyson; Wikiquote

I agree with the first part of this statement, but the second part makes my hair stand up: By that token, any and every evil that we have come to know throughout history, including notably Nazism, Communism and religious extremism, is turned into a good cause. A rather uncanny way to turn the underlying humanism of this statement and its owner upside down.

Dyson is a very respectable man, particularly adept at skillfully concise statements about mathematical or physical truth. Unfortunately, this quote is not one of them.