I am perplexed by the Us versus Them phenomenon. Try as I might, I have not been able to explain why it has such a powerful hold on so many of us. Let me try and work through it once again using a thought experiment. I would like you to stay with me as I do and to give me your feedback at the end. I imagine that I am invited to speak to a class of high school students in a city that I have never visited before. I arrive at the school and walk through a corridor into the class. In front to me I find 60 students of both genders wearing the school uniform and no other marks of identification seated in random order.