The emergence of the Progressive Christianity movement gives hope for a "rethinking" of churches' attitudes in the 21st century, writes Ian Harris.
Just over 100 years ago, the Protestant churches of Europe and North America convinced themselves that, with one more mighty missionary push, the whole world could be converted to Christianity. "The evangelisation of the world in this generation" was the catchcry of the World Missionary Conference, held in Edinburgh in 1910.
It was a confidence born of zeal, wealth and imperialism. European nations were dominant on every continent, and the churches believed they had the resources, personnel and opportunity to seize the moment for the Christian gospel. Now they had the will.
The basic impulse of the missionary enterprise has always been to "save souls". Traditional theology taught that only the church could guarantee everlasting life and everyone should be offered it, so Christians were obliged to spread the good news everywhere.
A century on, how things have changed! Though there are still missionaries active in the old pattern, for many churches in the West, the big question today is how to survive where they are, not how to project themselves abroad.
Little is heard now about saving souls - many doubt whether there is such a thing - and the proffered alternatives of an after-life in heavenly bliss or torment in hell have lost their persuasive power.
As a result, churches in most Western countries are shedding numbers and influence. That trend will continue, unless they set about seriously rethinking their heritage for the 21st-century world.
Which is why I see hope in the emergence of the Progressive Christianity movement in the United States, Britain, New Zealand and elsewhere. It is showing a willingness not only to do that rethinking, but also to express it openly within and beyond church life.
Constructive rethinking begins with asking the right questions. The Progressive Christianity Network in Britain poses them as: Can Christianity reflect modern society? Can Christianity be rational? Can the Church be inclusive?
Drawing members from all major denominations, the network says contemporary thought and understanding matter as much as scripture and tradition, and encourages debate over conformity. Its American counterpart sets the goal of building a new model of Christianity that is compatible with "deep spirituality, sound science, compassion for the needs of humanity, and respect for the environment".
Their starting point is not signing up to creedal statements, but simply: "We are Christians who have found an approach to God through the life and teachings of Jesus."
They welcome all comers "without insisting that they become like us to be acceptable" - believers, agnostics, conventional Christians, questioning sceptics, women and men, people of all sexual orientations, races and cultures, classes and abilities.
"We find more grace in the search for understanding than we do in dogmatic certainty," the British movement says, "more value in questioning than in absolutes.
"We know that the way we behave toward one another and toward other people is the fullest expression of what we believe."
In its own way, Progressive Christianity is missionary in its invitation to live according to the way of Jesus. But a new humility has replaced the triumphalism of 100 years ago.
The British network recognises the faithfulness of people of other faiths, while the American equivalent affirms that Jesus' teachings "provide but one of many ways to experience the sacredness and oneness of life".
So far, so good.
Something, though, seems lacking. Christianity is more than a set of values, a way to live, a path to wholeness and meaning, a vision of community. At its core lie profound insights into human nature (including powerful impulses to love and to hate, to create and to destroy), along with a dynamic that can transform individuals and communities; something traditional Christians rightly keep to the fore.
In the old paradigm, that transformation centred on Christ as the divine rescuer from sin and its consequences. Progressive thinking moves firmly away from that supernatural understanding - but in doing so, it seems to have jettisoned any concept of Christ at all. Part of its rethinking must be to rethink that, too.
For it is the Christ figure, much more than Jesus the man, that makes Christianity distinctive.
Physically and spiritually, Jesus belonged within the Jewish faith.
Islam reveres him as a prophet.
Only Christianity affirms him as the Christ, the one who breaks through the roadblocks to a new way of being and a new order of humanity.
One day, hopefully, Progressive Christians will find a way to affirm the Christ also - not in any supernatural sense, but as Christianity's unique and enduring symbol of love, grace and transformation.
- Ian Harris is a journalist and commentator.
