Another change revolves around the Internet. In this view, the Pegida people are just the usual frustrated lot looming at the edges of society. Now, emboldened by the reinforcement they find in like-minded communities online, they’re taking to the streets.

And a third is the persistence of regional differences. Though Pegida has drawn support in western Germany, it is strongest in the former East Germany. In the East, xenophobic attitudes are still more common than in the West, for a complex mix of reasons, including higher unemployment rates, but also because of feelings of inferiority.

We also have to ask what Pegida says about Germany, whatever its causes. It certainly indicates that the relative social peace we are experiencing right now is fragile. But it also shows how the country, still new to the multiethnic game, is struggling with its identity. It wasn’t until the 1950s that the first waves of immigrants arrived, the “Gastarbeiter” (guest workers) from Turkey and Italy who came to fill the labor gap in the country’s prospering postwar economy.

For decades, Germany was able to pretend that the guest workers were just that, guests. But the third generation of Turkish immigrants is now reaching adulthood. At the same time, immigration numbers are rising: Germany’s immigrant population grew by about 430,000 last year. Many came from the Southern European countries that still suffer from the euro crisis, but last year Germany also welcomed some 220,000 refugees, mostly from Syria, Eritrea, Serbia and Afghanistan.

The white face of German society is changing at a rapid pace. In this context, the Pegida protests are getting such attention because they act as a weekly checkup of German society. It’s as if every Monday, the news media are putting a trembling hand to the country’s forehead, checking its temperature, wondering whether our ugly, xenophobic past is taking over again. And we don’t have to look back to the 1930s to find that past; in the early 1990s, when the country last saw similar numbers of refugees, an irrational fear of foreigners taking the jobs of “real Germans” gripped the country, culminating in anti-immigrant riots in several cities, with several deaths, many wounded and thousands scared.

Last week, a 20-year-old refugee from Eritrea was found stabbed to death near his apartment in Dresden. Neighbors reported that swastikas had been painted onto the door of his apartment. Germans held their breath. Was this a neo-Nazi murder? Was there a connection to the Pegida rallies? Then, on Thursday, authorities arrested one of the victim’s roommates, another asylum seeker, who they say has admitted to the attack. Still, we don’t trust ourselves. Why should our neighbors? Why should you?

However the investigation turns out, I am an optimist, believing that we will not see history repeated. Germany has come a long way since even the early ’90s. And rather than causing violence, Pegida has set off a public debate on Germany’s national identity. This is long overdue. Prominent conservative politicians like Peter Tauber, the secretary general of the Christian Democratic Party, have demanded a new, clearer framework for immigration. Last week, Chancellor Angela Merkel declared that “Islam is part of Germany.” It was an assessment, rather than an ideological statement. It was the simple acknowledgment of a simple reality.