But today's middle-class boom is unlike the Industrial Revolution, in which rising prosperity became a catalyst for increased individual and political freedom. Those in the emerging global middle classes – from an Indian acquiring a flush toilet at home to a Brazilian who can now afford private school to a Chinese lawyer with a new car in the driveway – are likely to redefine their traditional roles, and in doing so, redefine the world itself.
"I would expect that as the global middle class gets transformed by the entrance of hundreds of millions of Indian, Brazilian, and Chinese families, the concept of what we see as the middle-class values may change," says Sonalde Desai, a sociologist with the National Council of Applied Economic Research in Delhi (NCAER). "Historically, sociologists have defined 'middle class' as those with salaries…. I think 'middle class' is very much a state of mind."
From Aristotle to Alexis de Tocqueville, Western thinkers have championed the middle class as essential for prosperous, enlightened societies. They held it up as the engine for economic growth, the guardian of social values, and an impelling and protecting force for democracy.
The new members of the middle class have been praised for their work ethic, like the shopkeepers, tradesmen, and professionals who spurred the Industrial Revolution.
But they also differ in fundamental ways. They come from communal societies that rein in the individualism prized in 1800s America. Their exposure to the pitfalls of the West's extravagant consumerism often makes them more frugal and environmentally conscious. And they are hesitant – for now, at least – to risk prosperity for political freedom.