But there is no reason it has to be that way. For most of human history we lived in small tribes of a hundred people or so, and everyone pretty much cared only for the people in their own tribe. But then we moved on to entire cities of thousands, where you likely didn't know everyone else, but it was still possible to care for strangers because they were still part of your "tribe". Then we moved on to nations with millions of people, and nationalism still proved to be effective.

So maybe we can someday go to globalism. Putting the whole of humanity inside your circle of concern, not just your friends and members of your tribe.

The reality is, your brain cannot process that many close connections so you are inevitably limited.

Well the same is true for countries, but nationalism seems to work.

Maybe. It would be nice.

That's how people with an inadequate exposure to multiple cultures during childhood work.... such as most Americans, sadly, who remain fantastically insular. As a British kid in US school for a year, I was astounded to find that of this group of "elite" children, only two (other than myself) had ventured beyond Illinois, and one abroad - to Canada.

Did you not also perceive that Illinois is in the middle of nowhere? If you're in England you might end up in Paris just on a bender (citation: http://www.dailymail.co.uk/news/article-2509837/Teenager-wen...).

Still, judging from the actions of the democratically elected UK government, you lot don't seem to do much better...

Oh, indeed. Geography is no small part of it. Folks from corners of the world in proximal contact with other cultures end up with far more cultural cross-talk and the ensuing ability to understand other cultures... or they have the inverse reaction, of outright xenophobia.

Our government isn't democratically elected - had they enacted the electoral reforms that they said they would, the next might have been - but they won't, and it won't be.