Solidarity is essential to democratic societies; otherwise, they fall apart. They cannot function beyond a certain level of mutual distrust or a sense on the part of some members that other members have abandoned them. Many view the development of an individualistic outlook as the greatest threat to solidarity. But this is closely linked to a diminishing sense of common identity.
It's no accident, for example, that Europe's most successful welfare states were created in ethnically homogeneous Scandinavia. People in those countries had the sense that they could understand their neighbours and fellow citizens, and that they shared a close link with them.
The challenge nowadays is to maintain that sense of intense solidarity amid diversifying populations. There are two ways to do this. One is to hark back to older modes of solidarity. French identity, for example, is based on the country's unique brand of republican secularism, known as laïcité. But France's efforts to shore up solidarity by insisting on laïcité and erecting a dam against Muslim immigrants are both ineffective and counterproductive, because they exclude from a sense of fully belonging to the nation many people who are already in France.
The other way to preserve solidarity is to redefine identity. All democratic societies are faced with the challenge of redefining their identity in dialogue with some elements that are external, and some that are internal. Consider the influence of feminist movements throughout the West. These are not people who came from outside their countries. They are people who, in some ways, lacked full citizenship, who demanded it, and who redefined the political order by obtaining it.
The great task is to calm the fears that our traditions are being undermined; to reach out to people who are coming to our lands from other countries; and to find a way of recreating our political ethic around the kernel of human rights, equality, non-discrimination and democracy. If we succeed, we can create a sense that we belong together, even though our reasons for believing so may be different.
But increasing individualism - a focus on one's own ambitions and economic prosperity - in many countries poses a stubborn obstacle to realizing this vision. Indeed, the utter lack of a sense of solidarity among so many people - horrifyingly evident in the U.S. health-care debate - is undermining the very basis of what a modern democratic society is.
A society's sense of solidarity can be sustained only if all of its different spiritual groups recreate their sense of dedication to it: if Christians see it as central to their Christianity, if Muslims see it as central to their Islam, and if the various kinds of lay philosophies see it as central to their philosophies.
Religion provides a profound and powerful base of solidarity, and to marginalize it would be a big mistake, just as marginalizing atheistic philosophies would be a mistake. Democratic societies, in their tremendous diversity, are powered by many different engines of commitment to a common ethic. They cannot afford to switch off any of these engines and hope to maintain a political community.
Historically, the political ethic of confessional societies has been grounded in a single, basic foundation. In Europe, various kinds of laïque societies have tried to invent themselves out of the ruins of the Christian foundation, but they have made the same mistake in another way, with a kind of Jacobin insistence on the civil religion of the Enlightenment.
Well, we can no longer have a civil religion - not one based on God, or on laïcité and the rights of man, or, indeed, on any particular view. We live in uncharted territory. We face a challenge that is unprecedented in human history: creation of a powerful political ethic of solidarity self-consciously grounded on the presence and acceptance of very different views.
This can succeed only if we engage in vigorous exchange with each other in order to create a kind of mutual respect for these different views. The advancing force of Islamophobia in Europe and the U.S., with its attempt to reduce Islam's complex and varied history to a few demagogic slogans, is the kind of utterly ignorant stupidity - there's no better description of it - on which democratic societies founder.
But that's true of any kind of dismissive view of the "other." Our societies will hold together only if we talk to each other with openness and frankness, and, in doing so, recreate a certain sense of solidarity from all our different roots.
Charles Taylor is professor emeritus at McGill University and permanent fellow at the Institute for Human Sciences in Vienna. His most recent book is A Secular Age.