The story goes that some Japanese businessmen wanted to decorate their shopping centre for the Christmas season, so they sent researchers to the UK to get some ideas. Some time later the shopping centre opened with great razzmatazz, and the assembled crowds were greeted with the sight, on the outer wall of the complex, of a giant Father Christmas nailed to a cross. People don’t usually confuse the two Christmas figures of Jesus and Santa, but I’m going to.
There’s more that links them. Santa is used as a stick and (literally, alongside a glass of brandy) as a carrot to improve behaviour in the young (‘he’s gonna find out who’s naughty or nice’), as is God for older people. Santa’s rewards are deferred within the few months of a child’s horizon; God’s to the horizon of death.
Although belief in Father Christmas is used as a standard example of a childish belief easily shed as we get older, belief in him is just as childish, and just as rational, as belief in God. And also, conversely, belief in God is just as childish, and just as rational, as belief in Father Christmas.
Greg Lake’s song I Believe in Father Christmas uses loss of faith in Father Christmas as a symbol of loss of faith in Christianity, made explicit in ”till I believed in the Israelite’. (In that way it shares with Blake’s Jerusalem the honour of being a song happily sung to celebrate the very thing it seeks to undermine.) Here’s the whole song:

They said there’ll be snow at Christmas
They said there’ll be peace on earth
But instead it just kept on raining
A veil of tears for the virgin’s birth
I remember one Christmas morning
A winters light and a distant choir
And the peal of a bell and that Christmas tree smell
And their eyes full of tinsel and fire

They sold me a dream of Christmas
They sold me a silent night
And they told me a fairy story
’till I believed in the Israelite
And I believed in Father Christmas
And I looked at the sky with excited eyes
’till I woke with a yawn in the first light of dawn
And I saw him and through his disguise

I wish you a hopeful Christmas
I wish you a brave new year
All anguish pain and sadness
Leave your heart and let your road be clear
They said there’ll be snow at Christmas
They said there’ll be peace on earth
Hallelujah noel be it heaven or hell
The Christmas you get you deserve

So how can I believe in Father Christmas? It’s hard not to, if I believe in Jesus. Both stories convey human truth. Belief in Santa accords perfectly with the worldview of a small child: most of what happens in their world operates outside the natural laws of grown-ups, so there’s nothing difficult or bizarre about the nice old chap in Coca-Cola red who delivers presents across the world. And the story of Jesus, a defenceless underclass baby containing the potential of the cosmos, is a perfect one for giving grown-ups hope.
Aidan Andrew Dun said that the world is not made of atoms, but of stories. He is making the same point as Sherlock Holmes, when he angrily scolds Watson for telling him that the earth revolves around the sun. Geocentricity and atoms may be true and real, but they are of no importance to our daily lives; stories on the other hand directly inform our minute-by-minute existence of trafficking power, love and ideas with our fellows. And, in another sense, even geocentricity and atoms are only comprehensible to us as stories. Don Cupitt rightly argues that any philosophy worth anything has to start from, and be based in, our ordinary lives.

The Christmas we get we deserve.

I wish you a hopeful Christmas.

God comes to grown-ups in the form of a story about a Christmas baby; and to infants as a story about a jolly chap with a sack. Both are true.