Atheists tend to think that religion is about God. Of course it is. But if that is all it is, it would hardly explain religion’s tenacity and power, its hold on the human imagination, and its strange capacity both to unite and divide.

Religion is also about identity. It is an answer to a set of questions that science cannot answer, perhaps cannot even understand. Who am I? Why am I here? Where do I belong? Of what story am I a part? How am I connected to those who came before me? How then shall I live?

The great religions answer these questions against the broadest possible background and in the richest possible way. They celebrate identity in stories, rituals, celebrations, prayers and holy days. They speak of the universe, creation, revelation and redemption. They show us role models of sages and saints, heroes and heroines, exemplary lives. They tell us who we are and what we are called on to be.

Religions are not the only source of identity. Some find theirs in nationhood, others in their work, especially if they see it as a calling. Some find it in a cause. Yet others find it in ethnicity. Some even find it in the football team they support (remember Bill Shankly’s “Some people believe football is a matter of life and death, but I can assure you it’s much, much more important than that”?).

Should we even have identities? There have been people who said No. There were universalists such as Socrates, who said: “I am not an Athenian or a Greek, but a citizen of the world.” There are cosmopolitans whose identity, like my grandmother’s recipe for chicken soup, is “a little bit of this, a little bit of that”. There are people who change lifestyles the way that other people change their clothes. There are even postmodernists who deny identity altogether. Life for them, as with advertising on television, is simply a series of episodes with no connecting thread.

One thing is clear: identity has become problematic in the modern world. The sociologist Peter Berger defined modernity as a state of permanent identity crisis. Many of the secular alternatives to religious identity proved terrifying in their consequences. National identity led to nationalism and two world wars. Ethnicity led to racism and the Holocaust. The “cause” led, among other things, to communism and Stalinist Russia. Even football, more harmless than most, can lead to violence. As for those who deny identity, it’s quite hard to be everyone in general without being anyone in particular. Even cosmopolitans tend to be comfortable in the company of other cosmopolitans, and feel threatened in the presence of other, stronger identities.

This is one reason why religion has returned, centre stage, in the 21st century, because of the waning of secular alternatives. Most of us need identity as our way of being at home in the world. It helps to be able to say: this is my story, this is who I am. It’s within our particular identities that we learn to live, love, create communities and cultivate responsibilities. The best identities speak to the better angels of our nature, especially when they include saintly role models, high ideals, and the imperative to love the stranger.

But there is a great danger, and those of us who are religious must be honest about it. Far too often in the past religious identities have been a source of strife. Identity can lead us to divide the world into two, Us and Them, the children of light against the children of darkness. The history of the great monotheisms has been written in the tears caused by clashing identities. The great unsolved problem facing these religions is: can we make space for one another?

I think we can. The paradox of identity is that it is precisely when we speak from within our particularity that we strike a chord with others of different particularity. You don’t have to be French to love Flaubert, Russian to admire Tolstoy, or Japanese to enjoy a haiku. Affirming our identity need not involve negating anyone else’s. I can say this is who I am, without saying or implying that this is the only way to be. If Jews, Christians and Muslims can rise to this generosity of spirit, then we can celebrate the fact that we each have our particular way of being at home within the glorious diversity of humankind.

Lord Sacks is Chief Rabbi of the United Hebrew Congregations of the Commonwealth