Perhaps Europe’s leaders should have been more alarmed when enthusiasm for unity began fraying even before the crisis. In 2005, French and Dutch voters blocked progress toward a European constitution. Meanwhile, the newly free countries of Central and Eastern Europe — Milan Kundera’s “kidnapped West,” disfigured by 45 years of Soviet occupation — hadn’t so much re-Europanized their economies as globalized them. The same is true of Europe’s rising generation; it knows the pleasures of a modern economy. But those are available globally to anyone with their level of wealth and privilege. Apart from that euro in their pockets, Europe’s young people do not feel Europe’s presence on a daily basis.

Leaders of opinion, commerce and government generally agree that the Continent could benefit from greater political unity, since globalization favors continental blocs. But the nations and peoples of Europe would have to give up great areas of sovereignty, and nothing has prepared them for this. At the rate things are going, if Europeans are asked to push for unity, they will refuse.

For that reason, Europe must find a new idea, a new vision, a mortar for the future. Familiar lofty principles will not be enough. The rights of man, pluralism, freedom of thought, free-market social democracy — all are in the nations’ constitutions; citizens don’t need the European Union to supply them.

How, then, to establish emotional ties to Europe?

Perhaps the answer is to conceive of a Europe in the flesh, with colors, smells, folklore, poetic force. And variety. The goal is not one formed on familiar principles — common language or history or bloodlines — but the very opposite: a supranational, fundamentally Continental cultural understanding and reference point. Mr. Kundera talks of Europe’s “maximum diversity in minimum space” — a notion perhaps as powerful as “liberté, egalité, fraternité,” or “all men are created equal.”