It is normal to hate what we fear, and it happens frequently, though not always, that we fear what we hate. I think it may be taken as the rule among primitive men, that they both fear and hate whatever is unfamiliar. They have their own herd, originally a very small one. And within one herd, all are friends, unless there is some special ground of enmity. Other herds are potential or actual enemies; a single member of one of them who strays by accident will be killed. An alien herd as a whole will be avoided or fought according to circumstances. It is this primitive mechanism which still controls our instinctive reaction to foreign nations. The completely untravelled person will view all foreigners as the savage regards a member of another herd. But the man who has travelled, or who has studied international politics, will have discovered that, if his herd is to prosper, it must, to some degree, become amalgamated with other herds.
Bertrand Russell