Theories about origins aren't much help either. Apart from the flaws in the Saturnalia theory noted by Jonathan Godfrey, while various ancient winter solstice festivals may have been antecedents to Christmas, the fact that they were usurped by the Christian festival centuries ago speaks for itself.
Christmas - like Easter - displaced the pagan festivals, rather than evolving out of them. Even where imagery coincided, as with the coming of light into the world, Christmas drew its meaning solely from the well of scripture.
That Christians took over symbols from pagan festivals underscores how complete the Christianisation of pagan cultures was. Christians had the confidence to appropriate such symbols for their own ends, imbuing them with new (Christian) meaning.
What we have seen over the past 50 years, however, is significant movement in the opposite direction. Christian Christmas traditions and rituals have been consciously marginalised or secularised, as attested by the demise of the primary school nativity play and the rise of the non-religious carol.
For Christians, the 1984 Band Aid hit Do They Know It's Christmas? was not only a question about starving children in Africa. It applied equally, albeit very differently, to the materially indulged but spiritually bankrupt children of the West.
In many ways what we now do at Christmas is an uneasy amalgam of the Christian and the secular.
We eat and drink, Santa bears gifts, a kaumatua may say a karakia, we sing carols - including O Come All Ye Faithful - but a reading or enactment of the nativity story is off limits.
Theologically this is a muddle. The Christ child needs to be in or out, faithfully celebrated or excised altogether.
If it is excision, some other meaningful and commonly agreed upon name and reason for the season need to be found.
Neither Saturnalia nor Santamas are likely to cut it. Nor is simply being together as family and enjoying a spirit of goodwill likely to provide sufficient reason.
Sadly, for too many, family and goodwill seldom overlap. Those who do enjoy family time need no additional stress-filled festival to do so, especially with New Year and summer holidays pending.
While non-Christians work all this out, Christians - who still make up 43 per cent of the population - might return to the biblical narratives and ponder more deeply the significance of what they celebrate at Christmas.
It would be naive to think that the secularisation of Christmas has not taken any toll.
At the heart of the biblical narratives are two truths.
The first is that in Jesus, God took on human form. Jesus was not merely a prophet or holy man but God's only Son - Immanuel (God-with-us). His birth was miraculous. His mother Mary conceived without sexual intercourse, under the power of the Holy Spirit.
This was no easier to believe then than now, as Mary's reaction to its announcement attests. But faith avers that nothing is impossible with God.
Secondly, Jesus came into the world to save people from their sin.
Yes, sin is still the underlying problem with the world. It alienates us first from God, then from one another, culminating in death. Only God can resolve this problem, and he has done so in his Son Jesus Christ.
Believing this doesn't come naturally, either. It requires both faith and humility, the acceptance that God has done what we cannot do for ourselves.
We are a society of mixed beliefs, and everyone has the right to celebrate in a way consistent with their beliefs.
Nevertheless, as long as Christmas bears Christ's name, and coincides with the church's celebration of his birth, it is unreasonable to ask Christians to surrender their longstanding proprietary rights to this festival.
Rather, a secular alternative should be instituted. It already has its own stamps.
• Michael Hewat is vicar of West Hamilton Anglican parish.
