What with all the crowds and the shopping and the formulation of complex family Christmas treaties, you may have missed the enchanting news about Richard Dawkins, author of The God Delusion. In a good mood Professor Dawkins dismisses all faith as “harmless nonsense... the great cop-out”. In a bad mood he tends to call it a wicked, “infectious virus”. He is not shy to air his views on the subject.

At which point I should say that — though not wholly of his mind — I actually have a lot of time for the Dawk. Organised religions do often abuse their position and their followers, and need to be told so; and his thesis is far more intelligently based than the infantile vitriol of Christopher Hitchens or the sneering cool of most media atheism. Moreover, Professor Dawkins' recent programmes on New Age superstition were more than welcome: the best TV moment of the year was the sight of a dishevelled woman earnestly explaining what DNA was — to the great biologist! — and then offering to “replace” the missing DNA from Atlantis, putting it into his cells by wiggling her fingers and blowing at him. I could watch that clip all day, just for his face.

But the really fabulous news I mentioned is that Richard Dawkins, Prophet of Atheism, has said in a BBC interview that he is not against “cultural” Christianity and “Yes, I like singing carols along with everyone else”. Which raises enough tantalising philosophical and ethical questions to keep us going till Christmas Eve. Dawkins sings carols? Does he sing all the words? Does he boom out lines about herald angels, holy nights, the tender Lamb promised from eternal years? Does he croon: “What can I give Him, poor as I am?” Does the polemicist who gave three eloquent pages to deconstructing the story of St Luke's Gospel happily warble O Little Town of Bethlehem and Once in Royal David's City? Does the man who says that religious education is tantamount to “child abuse” feel wholly comfortable crooning Away in a Manger?

Or does he censor the words? Do neighbours at Oxford carol concerts suddenly become aware that one pleasing baritone has abruptly dropped out before the first “O come let us adore him” and failed to return for the final fortissimo? How can his famous, well-modulated voice choke out the word “adore”, apropos a God he calls a “misogynistic, homophobic, racist, infanticidal, sadomasochistic, capriciously malevolent bully”?

Well, you see the pleasure. Rewriting the Dawkins carol sheet could keep us all busy. “God rest ye merry Gentlemen, pass on your DNA/ For genes are strong and se-el-fish and will find out a way”... “Silent night, Science is right”... “Away in a helix, no crib for a bed/ The little Lord Genome laid down its sweet head...” It gets tricky; I am having some trouble with the scansion of “While Schrödinger watched his cat by night”, but I'll get there.

But leave the poor man alone. The point is that he obligingly raises the more general question of how the unbeliever, the half-believer and the ex-believer should treat the cultural heritage of Christianity, especially at Christmas. As Aled Jones and Katie Melua averred on the Today programme yesterday, the carols are good tunes and fun to sing, and you needn't be immensely religious to enjoy them. I am certainly not naive enough to believe that everyone who sings them is burning with faith. Some are, and thus have no problem with the adoring, but I suspect that many approach carols in a spirit of cautious unexpressed hope — willing to leave the door just a crack open to the possibility that there might be something or Someone out there, beyond it all, incapable of being pinned down by science or reason but nonetheless wonderful and benign. That, combined with a certain respect for the generations who went before and a wistful longing for the “hopes and fears of all the years” to be resolved one day, whether before death or after, is a reasonable spirit in which to have a good old sing at Christmas.

But if you loudly and repeatedly make a career of denying any possibility at all of the reality of God, how honest is it to sing? How easy to reconcile? How insulting to those who mean every word of it? One can obviously do a bit of sectarian tourism: once at supper with the Chief Rabbi I did sing along with the Yiddish grace-after-meals. But then I am broadly a deist, and if Jonathan Sacks was prepared to tolerate our inaccurate pronunciation and weak grip of the tune, it seemed fair enough for dinner guests to give it a spin. Likewise I admit that the two million of us who sang “Wider still and wider shall thy bounds be set!” on The Mall in Jubilee year didn't honestly want to reconquer India.

But there are limits. If I found myself at a Nazi rally I would not sing the Horst-Wessel-Lied; if I were with the Druids at Stonehenge I doubt that I would don a sheet and join in hymns to the rising sun or whatever, because I think it is all fabricated modern nonsense. And if suddenly transported to that American church where they sing “God hates fags” (it's on Faith Central blog, click and see) and someone passed me a hymn sheet, I wouldn't join in. Not even hum along, however catchy the tune.

Well, it's something to think about in the pre-Christmas queues. Can you sing something while meaning the opposite? Can Professor Dawkins be truly merry at a carol concert while publicly excoriating the “time-consuming, wealth-consuming, hostility-provoking rituals and anti-factual counter-productive fantasies of religion...”?

Or should he stay true to himself, and stick to a verse or two of Frosty the Snowman?

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