When we survey the whole cultural history of humankind we find we have to define religion in much broader terms to do justice to the great variety of forms it has taken.

My preferred definition of religion is that of Italian scholar, Carlo Della Casa: "Religion is a total mode of the interpreting and living of life."

In this new secular age, religion is manifesting itself in a much more humanistic and naturalistic way than in the past.

We are coming to value what it is that all humans have in common, irrespective of class, race, religion, gender, or age. We are developing a growing concern for human rights. We have come to see that what used to be regarded as the divine attributes are actually human value judgments, expressing what our forbears found to be of ultimate concern to them.

It is these values which came to the fore when the modern secular world began to emerge from the 18th century onwards, and they gave rise to a whole series of emancipations - the democratic emancipation from absolute monarchy, the emancipation of slaves, the emancipation of women from male domination, the emancipation of the humankind from racist prejudice and the emancipation of homosexuals from homophobia.

Sadly, the churches have often been initially opposed to these emancipations. This showed they were no longer on the side of freedom and human justice, as they should have been, because they had become committed to outworn dogmas of the past.

This is why the churches have become increasingly marginalised from society. The new forms of religion, appropriate to the secular age, are more often to be found outside the churches than within them.

It is also the reason why para-religious movements are springing up outside the churches, such as the Ephesus groups in New Zealand and the Sea of Faith Network in several countries.

The erosion of church institutions does not mean the end of Christianity, for the latter needs to be seen not as something eternally fixed but as an ever-changing and developing process. The modern secular world is all part of that evolving process.

When Christianity emerged out of Judaism, Christians claimed it to be the legitimate continuation and fulfilment of the Jewish path of faith. Similarly, the modern, secular and humanistic world may be regarded as the legitimate continuation of the Judeo-Christian path of faith.

The churches must stop treating the secular world as an enemy to be fought and conquered and welcome it as the new form of the Christian tradition out of which it has come.

One of the first theologians to recognise this was the Anglican J. R. Illingworth, a man being read and valued when I was a student. As long ago as 1891 he warned Christians not to regard secular thought as the enemy of Christianity.

In an essay on the incarnation he said: "Secular civilisation has co-operated with Christianity to produce the modern world. It is nothing less than the providential correlative and counterpart of the incarnation."

Ludwig Feuerbach had implied the same back in the 1840s but it was to be more than a century before he began to be valued. The failure of the churches to recognise that the secular world has evolved out of their own central doctrine - the incarnation of the divine within the human world - and their claim that they alone are the true interpreters of Christianity, have meant that those outside the churches (now more than three-quarters of New Zealanders) are often failing to realise how much they owe to the Christian past.

The churches must now bear some of the blame that such people are cutting themselves off from their cultural and spiritual roots. As plants without roots wither and die, so cultures which forget their past do the same.

The most important task of the churches on entering the 21st century is to help the secular world to understand its Christian origin. The study of the past illuminates the present, but it does not dictate the future.

That is why the Bible remains an invaluable set of documents. We learn much from it but we are not bound by it.

During the course of the 20th century the idea of God as a supernatural, controlling, personal being was fading from general human consciousness. Oxford Professor of Theology John Macquarrie said: "There was a time in Western society when 'God' was an essential part of the everyday vocabulary ... but in the West and among educated people throughout the world, this kind of God-talk has virtually ceased ... People once knew, or thought they knew, what they meant when they spoke of God, and they spoke of him often. Now in the course of the day's business we may not mention him at all. The name of God seems to have been retired from everyday discourse."

We may illustrate this by noting how our common everyday speech has been changing. Once, on parting from others, we always said, "Goodbye," which is derived from "God be with you." Now we say, "Have a good day."

In the very last year of the 20th century, the radical theologian Don Cupitt made a study of the way our everyday language is reflecting the religious change that has taken place. He found, for example, that where once we would have spoken of God, we now refer to "life". We have created a whole new set of phrases including it, such as"Get a life."

Within the space of 100 years New Zealand has changed from being a predominantly churchgoing God-believing society to a predominantly non-churchgoing secular society. In 2000, the main-line churches showed little of the triumphant confidence they manifested in 1900 and they have now entered survival mode. Religion has become privatised and God has lost his public face. That much is plain for all to see.

But how are we to interpret all this? If we define religion in the supernatural terms encoded in Christian dogma, then New Zealand is fast becoming non-religious. But if we define religion in much broader terms (as I do), and if we acknowledge the secular world view to be the product and legitimate continuation of the ever-developing path of faith we call Judeo-Christian, we may come to an entirely different judgment.

New Zealanders generally, by their passion to combat apartheid and racism, to condemn war and violence, to promote tolerance of diversity ... manifest in these and other ways a genuine religious zeal. Insofar as New Zealand has been called the most secular country in the world, then we may well be in the vanguard of the new secular phase of religion, just as we were in the forefront in giving the franchise to women.

The most widespread religion in New Zealand today is what I have called elsewhere "religion without God", and which our leading citizens often refer to as "Christian values".* This is an edited versions of Lloyd Geering's Hocken lecture given in Dunedin this month.

* Lloyd Geering is a former principal of the theological hall at Knox College, Dunedin, and was the first professor of religious studies at Victoria University, Wellington.