New Delhi, June 1 -- There is a fascinating, unwritten law that governs the animal kingdom: even predators generally avoid destroying their own kind. Humans have long observed this boundary and applied it to our own social structures.

Today's proverb is a gritty, ancient Greek maxim: "Κόρακος κοράκου μάτι δεν βγάζει"-or, "The crow does not take the eye out of another crow."

It is a blunt, realistic commentary on professional solidarity, tribal loyalty, and the fierce codes of honour that bind certain groups together.

At its surface, the proverb draws on the practice of wildlife observation. Crows are hi...