My best friend during my youth—now my husband—is himself from Northern Ireland, an area where people who look absolutely identical to each other, eat the same food, pray to the same God, read the same holy book, wear the same clothes, and celebrate the same holidays have yet spent four hundred years at war over a relatively minor doctrinal difference they later allowed to morph into an all-encompassing argument over land, government, and national identity. Racial homogeneity is no guarantor of peace, any more than racial heterogeneity is fated to fail.

Source: On Optimism and Despair | by Zadie Smith | The New York Review of Books