The week of the United States presidential inauguration happened to coincide with the atheists' advertising campaign, "There's probably no God." Looking at these stories together can provide some important insights.

Recurrent themes in President Barack Obama's speeches have been the need to give adequate weight to the "common good" — to find a new balance of the "me" and the "we"; to cross boundaries that divide us; to care for others; to be inclusive; to fulfill responsibilities, not just claim rights; and to hold the future on trust for those who follow us.

Rev. Carol Finlay, a Toronto Anglican priest, points out that these are some of the beliefs the monotheistic faiths share, and what they teach as a basis for our personal and social lives. She writes: "They all emphasize putting the other before oneself; love for a transcendent Being first, then love for neighbour; special care for the poor, marginalized, older people, parents; rules of behaviour (holiness) with accountability (yes, even liberal Christians); that a meaningful life comes from service; there is meaning in suffering; … and the unseen is the most powerful aspect of the universe and our lives."

She asks, "Without religion's role, where do we find these values in our society as firmly and clearly stated? What would we lose if religion was taken out of the mix in our society?"

The secularists' — atheists' and humanists' — response is, "nothing". Indeed, they go much further. Many of them believe religion is seriously harmful, even evil. All believe religion has no valid role in our shared values formation and no place in the public square of a secular society. They base their arguments on the doctrine of the separation of church and state.

They are correct that "we can be good without God". But can we get our shared values across so powerfully or well if we exclude religious voices? In particular, these voices may be needed to activate all our human ways of knowing, not just reason, which the secularists see as the only valid way. In short, we need a conjunctive, not disjunctive, approach — we need both religion and secularism, and must build bridges between them.

Let me be clear: We are secular, democratic societies and there is rightly a separation of church and state. But that separation does not mean religious voices have no place. Rather, it means the state, and its laws and public and social policy, are not based directly on religious beliefs and laws as they are in Islamic societies such as Iran.

Democracy is founded on principles of liberty and equality. Its genius is that, at its best, it allows us to live peacefully together despite our differences by finding where we can agree and holding in creative tension the issues we disagree about, rather than engaging in destructive conflict.

To privilege secularism, as some advocate, is to contravene liberty and equality and to prevent democracy functioning properly — in short, it's anti-democratic.

I have long pondered why fundamentalist neo-atheists, like the scientist Richard Dawkins, are so passionate about their disbelief. Just read his book, The God Delusion, to see this, or consider the large amount of funds given to the "no God" advertising/proselytizing campaign.

Such passion seems to show that we all have a need for some form of powerful belief (or disbelief) in order to find meaning in life. Our most human characteristic is that we are meaning-seeking beings.

The Latin root of the word religion is religare — to bind together — and we humans need to bind together, not only to find meaning, but to form a society. So if we abandon traditional religions, how can we do that? The emergence of "secular religions" could be one response.

Science, for example, can function as a secular religion and does so when it becomes scientism. The same is true of ethics when it becomes moralism. It's also true of sport, and the combination of sportism with another "ism," nationalism, is especially powerful. And environmentalism is at least a secondary religion for more and more people — but even that has its disbelievers and critics! In short, we are witnessing the emergence of a very large number and range of secular religions.

None of these "isms" is harmful in itself, but they are harmful to finding a "shared ethics," as I believe we need to do when they are promoted — as, for instance, Mr. Dawkins does with scientism — to deny any space for spirituality and traditional religion in the public square.

Secularism, the most encompassing "secular religion", functions as a basket holding all the others and we also need to understand that it is not neutral, as atheists and humanists claim. It too is a belief system used to bind people together. Consequently, it is inconsistent and unjust to exclude religious voices from the democratic public square on the basis that views based on belief systems have no place.

We urgently need to engage in an ongoing search for a "shared ethics" in our local, national and global societies. But we can't possibly hope to find that unless everyone, both people who are not religious and those who are religious — and, if so, no matter which religion — can participate in that search. That requires religious voices to be heard in the public square.

This search will help us to recognize that although we might disagree with “the other side” on some issues, we can agree with them on others, and that will allow us to experience ourselves as belonging to the same moral community.

There will be groups at either end of a broad spectrum of values who will never buy into a shared ethics, but the vast majority of people can cross the divides between them — including the secular/religious one — to find common ground.

We need a shared ethics to "hold on trust" for future generations, not just our physical world, but our metaphysical one – the values, principles, beliefs, stories and so on that create and represent the "human spirit". In other words, that which makes us human.

Margaret Somerville is founding director of the Centre for Medicine, Ethics and Law at McGill University.

Margaret Somerville is Professor of Bioethics at the University of Notre Dame Australia School of Medicine (Sydney campus). She is also Samuel Gale Professor of Law Emerita, Professor Emerita in the Faculty...