Certainly, Al-Qaeda’s terrorist attacks, the rise of China and wars in Afghanistan and Iraq seem to confirm this notion. Yet, as Moises Naim, the former editor of Foreign Policy Magazine points out in a recent article , most conflicts have lately been within civilizations than between them. Islamic terrorists have killed more innocent Moslems than anybody else. Ditto the fight between Shiites and Sunnis. And the source of the “Arab Spring” is homegrown. Indeed, the main source of global conflict, Mr Naim suggests, stems not from a clash between civilisations but  rather the changing fortunes of the world’s middle classes inside them.
 
The observation rings with truth. In the developed world, the middle classes of Europe and the United States are getting poorer and feeling mad about it. Result? In the United States, the rise of the Tea Party – and the very real possibility of a sovereign default. In Europe, angry protests in Spain, Greece and France over austerity measures – and the quite possible collapse of the eurozone.

Meanwhile, in the developing world, a new middle class, while not enjoying the same standards of living as its rich world counterparts, is consuming food, clothes, medicines, electronic goods and new housing like never before. Yet that prosperity inevitably brings other aspirations, especially better political representation and all manner of better public services. The new middle classes of India, China and Brazil often feel frustrated not because they want more but because they want better.

Chile is a case in point. It is often held up as one of the most economically successful and politically stable countries in the world. It also has a middle class that has continued to grow. And yet huge middle class street protests have become a recurring problem for President Sebastian Piñera. In June, some 80,000 students took to the streets to demand changes to the education system – the largest protest since Chile’s transition to democracy in 1990. In response, Mr Pinera set aside $4bn to improve education. And on Monday, faced by increasing unpopularity, he reshuffled his cabinet. “We are being put to the test by a more powerful citizenry,” he said. “Our institutions, our leadership, are being tested by citizens who are more empowered, who are demanding greater participation, and, above all, greater equality.”

Mr Pinera usually has a tin ear when it comes to politics, but here he was quite right. And it is true elsewhere in the world too.