I'm back from Europe. Though I'm still playing catch up, here are a couple of observations from my travels:
1. I've often heard people claim that "You can become American, but you can't become French." All my experience in France contradicted this - everywhere I looked I saw extremely assimilated Africans, Asians, and yes - Arabs.
2. Predictions that France is going to be taken over by Islam look largely fanciful. Admittedly, I didn't hang out in ethno-religious enclaves. But I haven't been to France in seven years, and it didn't seem any more Islamic than the last time I was there. Frankly, it's easier to notice the Islamization of Fairfax, Virginia than Paris, France.
3. Seeing a bunch of French cathedrals makes me even more skeptical of the claim (made by Larry Iannaccone and others) that people weren't more religious in earlier centuries. If people weren't far more religious in the Middle Ages, why did they pour such a high fraction of their surplus wealth into century-long religious architectural projects? You could say "It was primarily rulers, not donors, who allocated the funds," but that just pushes the question back a step. Were rulers vastly more religious than the masses? That's hard to believe. Were rulers trying to impress the masses by building churches? Well, why would churches impress the masses unless they were highly religious?
4. Religious architecture and art were to medieval feudalism what advertising and commercialism are to modern capitalism: A rather effective way to build support for the status quo using aesthetics instead of argument. My claim, in short, is that Notre Dame played the same role during the Middle Ages that fashion magazines play today. Notre Dame was not an argument for feudalism, and Elle is not an argument for capitalism. But both are powerful ways to make regular people buy into the system.