One of the charms - and perversities - of the English language is that it can be ferociously precise in such matters as the difference between continuous and continual or the nuances of meaning among ease, leisure and idleness, yet basic concepts such as equity and religion remain undefined. Humanism is another such word.

As a young Catholic growing up in the west of Scotland, I first met the word in contexts inhabited by similar monsters such as communism and anarchy. Clearly humanism was a bad thing. Imagine my confusion then when I learned that the thinking which underpinned the Renaissance (a good thing) was also described as humanism. Were these two totally different uses of the same word, or had the context changed so fundamentally that what was good in 1560 was bad in 1960 - like burning heretics?

Sure enough, it is in the nature of abstract ideas that their meanings evolve. Democracy in the 18th century had connotations of mob rule and domination of the best by the many (perish the thought), while for Demosthenes it didn't involve very many people at all.

Music once had something to do with the Muses, while sophistication wasn't very different from casuistry. That is why humanism can mean such different things to different people. A value-system derived from the human perspective may be perceived as base compared with the transcendental perspective, or magnificent against the backdrop of a million years of human development. As the man said: "Things look different from different places."

To many readers that idea may seem trite, even self-evident, yet the implications for our cherished belief systems are enormous. If ideas such as humanism, democracy, equity, justice and truth have evolved over the past 2,000 years or more, might the same not be true of religion, divinity, the spiritual, morality - and humanism?

And, if so, how reliable are all the esoteric distinctions we have been busily creating and refining for the past 400 years or so, and for which so many people have died? I should like to propose that many of these dichotomies are in fact obsolete and unhelpful.

I arrived at this view by a lengthy and at times painful journey from Catholicism through secular humanism to where I am today. Humanism is in many ways a natural alternative for those disillusioned with Catholicism. Revelation is replaced by reason; absolute authority by pluralism and tolerance; superstitious tradition by progressive scepticism; and divine grace by human rights.

That is why humanist values and perspectives are now so prevalent in advanced societies, even within the traditional religions. Its one major shortcoming, I discovered through personal experience, is an under-estimation of the importance of the non-rational (as distinct from irrational), the affective, the spiritual in human experience.

No doubt because the origins of modern humanism lie in a rationalist revolt against the authoritarian anti-rationalism of mainstream Biblical Christianity, the emphasis in humanism remains on a responsible, rational (albeit humane) approach to the problems of human life.

THIS makes for good social policy, sane economics and an admirable approach to world development but is less immediately relevant to the private world of grief, loneliness, fear and doubt. It is no accident that the mainstream religions, with some 5,000 years of experience behind them, have developed elaborate and comprehensive approaches to these aspects of life: ritual, prayer, reflection, confession and so forth.

While my early personal experience was of mutual hostility and incomprehension between the forces of Faith and Reason, I was to discover 20 years later that this need not be the case. There are religions which feel no need for dogma and authority and can, thus, very successfully combine the strengths of rationalism with sensitivity to people's spiritual needs.

Probably the best known is Buddism, which insists on no unchanging doctrines but only that each individual must search within her/himself for truth, understanding and ethical direction.

A similarly non-dogmatic approach is to be found in branches of Hinduism and in the Chinese Taoist tradition. Closer to home, I was to discover that throughout the history of Christianity there has been a persistent anti-authoritarian tradition, represented today by the Society of Friends (Quakers) and the Unitarians (in the US Unitarian-Universalists), both of whom are content to accept their rich Christian (indeed, Judaeo-Christian) pedigree, building on it to seek the truth wherever reason and reflection lead.

There is even a strand of religious humanism, well developed in the US but more apparent on this side of the Atlantic as a variant of other traditions than as a distinct approach in its own right. And, of course, all of the major churches have a large, and growing, liberal wing which is more often than not recognisably humanist (or at least rationalist/ naturalistic) in character.

Could it be, I wonder, that there is no substantial theological, philosophical or ideological dichotomy between the rational and the scriptural; the naturalistic and the transcendental; the secular and the sacred; but rather a much simpler confrontation between the interests of the organised churches and the freethinking approaches of non-credal traditions, the humanists and the liberal wings of all the major denominations?

My personal experience, confirmed by extensive study, indicates that there is no necessary contradiction between a rational approach to human problems and an honest, humble approach to the spiritual side of life. Difficulties arise only when some authority claims a monopoly on eternal truth - eternal, that is, until the next Vatican Council.

This is well illustrated by the notion of God (the Divine, the Godhead, the Absolute). Many modern writers have demonstrated how our ideas about the divine have evolved over the span of recorded history (and, presumably before that, but it is difficult to prove) in just the same way as have our ideas about the natural world, government, economics, justice and social organisation.

From animism through polytheism and monotheism we have arrived at the point where modern theologians define God in terms like the ground of our being, ultimate reality, or as a conceptual construct. From such positions it is the shortest of steps to the non-credal view that if there is an order of existence beyond the natural, then we cannot, by definition, know and say anything about it.

That is not to say that there isn't an issue: people have been trying to get their brains around the notion of the ultimate nature of existence since we lived in caves, and they're not going to stop now. We have arrived at the point where God is not so much a definable entity as a convenient piece of shorthand to encompass that long-running debate.