Another issue which being in the Czech Republic has given me some ideas about is about race/ethnicity, and what's going on historically right now in terms of race.
Firstly, I suppose, it's interesting to note the incredibly intolerant history of race and ethnicity in Europe. It is probably equally prevalent in every other continent, but previously I had sort of been of the notion that Europe was, at the least, given more to ideological/religious feuds, and due to the ethnically homogenous nature of Europe hadn't really distinguished racially between Europeans.
Well, it seems that the question of the "ethnically homogenous nature of Europe" is what I had missed. In the era passing forward from the Middle Ages, people lived in small villages, tribes, small city states and Duchys. Many spoke their own regional dialects and languages. But all had "Christianity," as it was united by the Church under the Roman Empire. The exception was the tribes of Jews that were throughout the land.
During this period, it seems to me (from an admittedly not very highly studied vantage point--my knowledge of history crystalizes much more clearly after 1900) that there weren't very many huge ethnic feuds. Now, partly this has to do with the fact that it is impossible at that point in history to actually destroy an entire ethnicity. The tools of mass murder were yet to come. But overall, people mostly kept to their small, local communities. The "other" was out of sight, and out of mind.
This changed after the Schism. Although this didn't create "ethnic" divisions, it did create another major identity division: Catholic or Protestant. And what, I suppose, is key is that the people who were divided were previously people who were in close proximity. And this is during the period where Europe is getting slowly smaller: the Kingdoms have mostly gotten large and intertwined through trade (during the trade revival of the 1600s), so suddenly these people were in close divisions. If you want to imagine what such a world looked like, imagine if all of Europe was Northern Ireland in the 1950s - 1980s.
I'm ignoring, of course, examples of "top down" persecution. It's one thing when King Ferdinand signs the order to persecute Jews, I'm focusing on mass movements of intolerance.
So at the end of the Schism, a peace is signed, which tells each King/Prince that where they rule, they decide the religion. And what that does is enforce homogeny in each community. There is a brief and catastrophic period of exoduses as Catholics flee to Catholic countries and Protestants flee to Protestant countries.
Nationalism, during this, has been on the rise. During the 1800s, it really peaks. The 1800s is the peak of nationalism. And this nationalism is not based on kings or kingdoms; the intellectuals of the time are trying to base it on something "historical" or "scientific." Hence you have the great frauds (neanderthals spoke German! ancient texts referring to the Czechs!), attempting to define the countries as more than just a temporary boundary created by history: countries are collections of a certain kind of people.
And they decide to use language as the identifier, and that identifier becomes race. Now, at the time of the 1800s, there were many Germans outside of Germany; some in Czechoslovakian regions, or in Austrio-Hungary, or in Prussia; and all of those people were mixed as well. As well as the French, or the Italians. Switzerland still represents that sort of mixture: after all, thanks to its long reign of peace, its ethnic makeup hasn't changed much since the 1400s, when the peace was first crystalized.
Eugenics enters the scene, and tells people that race is absolute. Meanwhile, there is a great rush of people to the big cities: cities which are much more ethnically complex than their home villages. They see The Other every day. And when they hear about Germany's actions, for good or for worse, they're constantly seeing Germans. Nationalist propaganda at the time (until pretty much World War II, sometimes even later) was based on vilifying the people who lived in those countries. It's not just that Kaiser Wilhelm is evil: the Krauts are evil. So how do you treat those nasty krauts who are in your workplace? What if one of those Krauts is your boss in the factory?
These people are, for many other reasons (see previous post) very unsatisfied. And a racial politics suits the up-and-coming Hitler. And during World War II, Germany, and various lands Germany held, became very very ethnically homogenous. Jews, gypsies, and other misplaced minorities were liquidated. Then, at the end of World War II, the counter swing: Germans were evicted from all the lands outside of Germany. Germany responded by evicting whatever non-Germans existed. Jews were still persecuted in areas of Poland. Poles were resettled thanks to the moving of the borders of Poland; Hungarians and Romanians settled within their own borders too.
The result of World War II is that all of the nationalist boundaries of the 1800s became ethnic boundaries. And since at the point of World War II, your community is your nation, that was enough to bring a sort of ethnic peace in Europe.
The exception is Yugoslavia, under Josef Tito, which did not go into that repopulating mode. But as soon as Tito's rule fell, Yugoslavia quickly tried to match the rest of Europe (not deliberately, I don't think) in creating nations based on language-ethnic homogeny. And of course, because of the very interspersed nature of these communities, it meant a lot of repopulation and depopulation.
None of this, to be clear is a good thing. All of the events which lead to the ethnic homogeny of Europe today (even the former Yugoslavia is homogenous to a degree which it never was to the past) were catastrophic, traumatic events for Europe.
But something reverse is happening now. But before I get into that, a word about colonies.
The biggest exceptions (there are a few) to the homogenization of the 20th Century is a side-effect of the collapse of the British and French Empires, where many of the peoples of the colonies came to their mother country to settle permanently. This is seen in "Londonstan," the part of England which is more culturally diverse than all the rest of the island combined. The suburbs of France have the same effect with many of its African colonials. And the racial tensions these have created are huge. The only ethnic hot-spots in Europe today are precisely those places that have races in contact.
Going back to the process of reversal that is going on now:
Previously, these conflicts have occurred every time the "horizon" of what your community was expands. The reason that World War II set off Europe's repopulation is that Germany, not content to sit in its own borders, intersected with all of the other nations. And where it went, it tried to ethnically homogenize. This created a lot of ethnic tension in Europe. Which, by the way, led to people distrusting Germany for half a century, not based on any one leadership, but based on the concept of Germany as a whole. "Germany" is dangerous if united.
Globalization is expanding the horizon of one's community again. The Schengen Free-Movement Zone makes it as easy for a Bulgarian to live in London as it is to live in Bulgaria. There is a huge movements of people to wherever it is that they can make the best living. This has, of course, created a lot of anxieties in areas where, previously, "the other" was elsewhere rather than here. Europeans have come to live with the idea of "the other, elsewhere" but as yet has not learned to deal with "the other, here." This is like the aftermath of the Schism's peace: other religions will be tolerated in other countries, but not in our own. Out of sight, out of mind.
This is a very complicated question, one which nobody has really solved anywhere. But it is the problem of Europe in the 21st Century. You'll notice that this question sort of bubbles near to the surface whenever the entrance of Turkey into the E.U. is discussed. After all, Bulgarians and Poles may be ethnically "other" from Brits and the French, but they're not considered religiously other; and especially today, there is a much more sour history between the West and Islam. This is an "other" which Europe is clearly not prepared to engage with ("here", at least: they're good friends with Turkey when Turkey is "there"). They will stall Turkey's membership into the E.U. until they're ready to have "the other, here."
And we need to figure out "the other, here" very soon.