An eye for an eye?

“I and the public know

What all schoolchildren learn,

Those to whom evil is done

Do evil in return.”

– W. H. Auden

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“An eye for an eye, and soon the whole world is blind.” – Mahatma Gandhi.

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I, for one, am quite confused!  Maybe the linguists have ground breaking interpretation for this. But then whats’ with, “do evil in return?”. That’d lead to the whole world going blind … choice is mine … or your’s.