Race and social recognition
Robert Henderson
The general reason why racial and ethnic differences result in hostility between different groups is simple: homo sapiens is a social animal.
Being a social animal requires members of the social group to use signals, both physical differences such as smell or physical differences and/or behavioural changes such as the use of calls to allow other members of the group to identify who is and who is not within the social group.
Human beings require such signals, and especially behavioural ones, to allow other humans to identify a group member. Of course humans are better at the recognition game than any other animal. David Hume put forward the idea that a human would identify with other humans up to a point. For example, an Englishman travelling in China would welcome the company of another Englishman first, then the company of a Frenchman, then the company of a or German more than he would a Chinaman .
Finally, however much liberals claim physical race is of no consequence humans give the lie to this in racially mixed societies by disproportionately take taking as sexual partners those of the same general racial types. This is unsurprising because there is such huge physical differences, for example, between the Nordic type and African pygmies.
Living In A Madhouse 