Insularity is the foundation of ethnocentrism and intolerance; when you only know of those like yourself, it is easy to imagine that you are alone in the world or alone in being good and right in the world. Exposure to diversity, on the contrary, is the basis for relativism and tolerance; when you are forced to face and accept the Other as real, unavoidable, and ultimately valuable, you cannot help but see yourself and your 'truths' in a new - and trouble - way.