The worst part of it is that my response to the film - a fantastically sentimental (and sentimentally fantastical) fable in which the real Father Christmas descends temporarily on New York to take a job as Santa Claus in Macy's department store - is so seemingly inexplicable. I don't even have the excuse that it is an unarguably great film (although it did win three Oscars). Made in 1947, directed by George Seaton and starring Gwenn, Maureen O'Hara and John Payne, also notable for the debut of Natalie Wood (playing the seven-year-old Susan Walker), it is described by Halliwell as a 'mainly charming comedy fantasy which . . . does suffer from a few dull romantic stretches'. I happen to think it is much better and more interesting than that, but why it makes me cry so much is still a bit of a mystery.
The film's malignant psychiatrist Mr Sawyer (who has Kris Kringle temporarily committed to the Belle Vue mental asylum) would doubtless have his own theories about that. Perhaps I have never appeased the disillusioned child in me, the child who kept himself awake one Christmas Eve in order to discover his father stealthily (but not stealthily enough) creeping up the stairs to his bedroom to fill his Christmas stocking - perhaps that's why I still feel this strange compulsion to view again and again a film whose resounding message is that, yes, Father Christmas does exist.
And perhaps (Mr Sawyer might further speculate) I watch the film not merely to recapture my childish faith in Father Christmas but, more importantly, my childish faith in my father - the man who lied to me, who deceived me, who tried to make me believe in a fiction whose hero I caught him impersonating. Perhaps (as Mr Sawyer tells Alfred, the endearingly naive, overweight 17-year-old cleaner who likes to dress up as Father Christmas because he enjoys giving children presents) I have a Santa Claus fixation which, in its turn, is the unconscious expression of a hatred of the father. And perhaps not. 'Gee,' as Alfred says damningly when he learns of Mr Sawyer's theories concerning him. 'I hate my father, and I didn't even know it.'
But if I cannot explain why I find it so compelling that may be appropriate, in its way, since Miracle on 34th Street is a film that brims over with distrust for theories, a film filled with a hatred of explanation. 'There's a lot of bad -isms in the world,' says Alfred, the idiot-savant who is also the movie's conscience, and Miracle on 34th Street attacks several: Freudianism, empiricism, rationalism, capitalism, to name some. These are the tools with which the worldly, the disillusioned and the degenerate try to expunge the miraculous from the world, or, in the film's terms, the tools which they use to try and disprove Kris Kringle's assertion that he really is Father Christmas. He is psychoanalysed, interrogated and eventually, in a wonderful twist to the genre of the courtroom drama, tried in a court of law. His triumph (which is, it is clear, a metaphorical as well as an actual triumph, a victory for the imagination over common sense) takes the form of a cunning reversal: the forces of rationality and the institutions of the rational, adult world are made to affirm the power of the irrational world of fantasy for which he stands. 'The state concedes the existence of Santa Claus,' the prosecutor says, and the clinching legal evidence that Kris Kringle is who he says he is is provided by the state postal service. By delivering 50,000 letters simply marked 'Father Christmas', no address supplied, to the courtroom, the US Mail confirms his claim to be the one and only Santa.
The mailmen who deliver this evidence are metamorphically transformed in the act of doing so: tramping into the courtroom with their bulging sacks, they have themselves been surrealistically altered into myriad Santa Clauses bearing bags full of gifts. Kris Kringle alters everything and everyone with whom he comes into contact, which is the key to the film's most vital meanings. He is a symbol of the artist, blessed with the powers of imaginative transformation, able to redeem the mundane world by dreaming it to be other and then realising those dreams. He is also the artist as impresario, one who enables others to be artists and to reinvent their lives through fantasy. Early in the film, Macy's sales manager ponders Kringle's apparent lunacy, wondering whether he is 'just crazy like composers, or artists'. That is, in fact, just the way in which he is crazy.
The film contains a particularly moving scene (well, moving to me, anyway) in which Kringle teaches the young Susie to untether her imagination. 'Do you know what imagination is?' he asks her, to which she replies with the commonsensical cynicism taught her by her mother: 'That's when you see things and they are not really there.' Well, Kringle replies, 'that can be caused by other things too'. (He means drunkenness, which is one of the movie's sub-themes, its emblem of irresponsible, bad-faith fantasy which is mere sad escapism: the Macy's Santa whom Kringle replaces is a pathetic sot who is incapacitated by Jack Daniel's on the day of the Christmas parade). Kringle goes on: 'Imagination is a place by itself, a separate country. You've heard of the French nation, the British nation, well, this is the imagination. It's a wonderful place. How would you like to be able make snowballs in summertime, or have a ship all to yourself that makes daily trips to China and Australia, or how would you like to be the Statue of Liberty in the morning and in the afternoon fly south with a flock of geese?' She is won over (who would not be?).
Miracle on 34th Street is a parable about the power of the imagination and at its heart lies a conversion experience: the apostasy of Doris Walker and her daughter, Susie, from their cynical, Doubting Thomas attitudes to fantasy, and their conversion to the true faith of Santa Claus. 'I think we should be realistic and completely truthful with children,' says Doris near the start of the film. 'We shouldn't have them grow up believing in a lot of legends and myths like Santa Claus.' When Susie meets Kris Kringle she pulls his beard and, convinced that it will turn out to be false, is surprised to find that it 'doesn't have one of those things that goes over your ears'.
Susie and her mother, Doris, begin the film believing they know the difference between art and life, between the imagined and the real worlds. Doris is, herself, an artist or an impresario of kinds, the organiser of the Macy's Christmas parade, but to her the pageant is, merely, artificial: she is the creator of a fantasy in which she doesn't believe (she goes home once the parade has begun, not bothering even to see it) and which she considers an imposture on the truth. Susie, watching the parade from Tom Gailey's apartment window, doesn't participate in it but criticises it: analysing the pageant, she keeps her distance from it, solemnly telling Tom that of course the hot-air balloon giants aren't real, just elements in a stage set. Mother and daughter's distrust of fantasy, we learn, is the product of an emotional wound: Susie never knew her father, who divorced Doris when Susie was a baby; Doris tells Tom that if you encourage children to believe in fairytales they will 'grow up considering life to be a fantasy, instead of a reality, they will keep waiting for Prince Charming to come along and when he does he turns out to be a . . .' She breaks off.
But Doris and Susie will learn that fantasy can become reality and that to dream of transfiguring your life may also be to change it. Susie's dream of a house (which is what she asks Kris Kringle to give her for Christmas) is really the dream of a mother and a father and a family life. She dares to dream it up and is rewarded by having the work of art forged by her imagination turned into a reality. Father Christmas does exist, after all.
And that is probably the real reason why the film - however sentimental - makes me cry. Because it proposes a world where Father Christmas is alive and well and living in Manhattan, where the gap between fantasy and reality, between our dreams of our lives and the reality of them, has been miraculously collapsed. Because it proposes a world where the bright imaginings of art seem as real, and as tangible, as reality itself. And because it proposes a world that most of us grown-ups, who know so well the difference between reality and the imagination, between truth and art, realise is lost to us.
'Miracle on 34th Street' will be shown on Channel 4 at 2.35pm on Christmas Eve