[T]he twenty-first century truly began on September 11, 2001, ten years later, when planes slammed into the World Trade Center and the Pentagon.

The twenty-first century will be the American century.

Du Bois, in The Souls of Black Folk, argued that the theme of the twentieth century was the color line. In my view, the theme of the twenty-first century is immigration. Everything rotates around it: climate change, Covid-19, populism from Trump to other “aspirational” dictators, global finance, etc.

Histories of 20th century art will be portraits of the time and place in which they were written.

U.S. hegemony in the post–Cold War era was like nothing the world had seen since the Roman Empire. Writers are fond of dating the dawn of “the American century” to 1945, not long after the publisher Henry Luce coined the term. But the post–World War II era was quite different from the post-1989 one. Even after 1945, in large stretches of the globe, France and the United Kingdom still had formal empires and thus deep influence. Soon, the Soviet Union presented itself as a superpower rival, contesting Washington’s influence in every corner of the planet.

There are two ways to tell the story of the twentieth century. You can describe a series of wars, revolutions, crises, epidemics, financial calamities. Or you can point to the gentle but inexorable rise in the quality of life of almost everybody on the planet: the swelling of income, the conquest of disease, the disappearance of parasites, the retreat of want, the increasing persistence of peace, the lengthening of life, the advances in technology.

The twenty-first century has begun with an American success that on the surface looks like not only a defeat but a deep political and moral embarrassment.

"The people who invented the twenty-first century were pot-smoking, sandal-wearing hippies from the West Coast like Steve, because they saw differently,” he said. "The hierarchical systems of the East Coast, England, Germany, and Japan do not encourage this different thinking. The sixties produced an anarchic mind-set that is great for imagining a world not yet in existence.

Old institutions have shattered, but new ones have not yet emerged. The twenty-first century will be a period in which a range of new institutions, moral systems, and practices will begin their first tentative emergence. The first half of the twenty-first century will be marked by intense social conflict globally. All of this frames the international struggles of the twenty-first century.

When I was growing up in the 1950s, the twenty-first century was an idea associated with science fiction, not a reality in which I would live. Practical people focus on the next moment and leave the centuries to dreamers. But the truth is that the twenty-first century has turned out to be a very practical concern to me. I will spent a good deal of my life in it.

New York is such an instrumental city for art, and it’s extraordinary the impact that America’s had in art history, especially in the 20th century.

[<nowiki/>20th Century has been called] the century of extremes, [...] in which human vices reached unfathomable depths. [She notes that it has been] a century of great progress [and in some places of] unprecedented economic growth. [At the same time, however, poor urban areas face a bleak future of] overcrowding and a disease pattern linked to poverty and an unhealthy environment.

The birth of the 20th century was like a flaming sunrise. More was expected of the century than any other. So much had been achieved in the previous one that it seemed sensible to expect that henceforth the world's triumphs would far outweigh the disasters.

The twentieth century was like twenty years' worth of change at today's rate of change.