We love Cinderella because she's adored for who she is, even when in rags
Why does the Disney corporation imagine that there is an audience for yet another version of Cinderella, now appearing on screens everywhere (directed by Belfast man Kenneth Branagh and featuring Lily James with an 18-inch waist)? Possibly because Cinderella is the most popular child's fairytale in the world.
The folklorist Bruno Bettelheim counted 345 versions of the Cinderella story, including an exceptionally cruel Scottish version, Rashin Coatie, and the Chinese version - probably the original - written around 850 AD, in which Cinders is called Yeh-hsien.
Sam Goldwyn, the movie mogul, always said people love story repeats: "If they liked it once, they'll love it twice." If they liked Cinderella once, they'll love it 345 times.
I have a feeling that feminists may disapprove of the Cinderella story; so a little abandoned girl gets to marry a prince? Shouldn't a modern woman aspire to become an international human rights lawyer (and then marry a prince - ie George Clooney)?
I am sure I thought Cinderella was shallow pap when I was younger, but as the movie critic of the New Yorker said about the new Disney production: "Some myths just will not go away." It's bigger than you are.
And, Bettelheim, in his famous study The Uses of Enchantment, claims that the Cinderella story is far from being shallow pap: as a psycho-analyst treating disturbed children he affirmed that fairytales "help a child find meaning in life".
The child can perceive good and evil through such stories - and can see, by the way, that evil also has its attractions. Many "evil" characters in fairytales - often women - are powerful. Understanding this is a moral lesson in itself.
The Freudians see Cinderella as a fable about sibling rivalry: Cinders's life is made miserable by her mean and jealous step-sisters.
Step-sisters often substitute for actual siblings in fairytales because the child does not want to acknowledge that their real siblings would be so nasty, so they are reinvented as usurpers, or step-siblings.
Yet the step-family, in reality, existed. Marina Warner, in From the Beast to the Blonde, looks at the statistics, in times gone by, of widowers remarrying, and they were exceptionally high: in France, 80% of widowers remarried within a year of losing a first wife, and the statistics were probably similar elsewhere. (Then, as now, women as widows - or divorcees - remarried less frequently than men.) So many a child would have experienced a stepmother, who might often have brought her own children into the family home.
The stepmother might often favour her own daughters over the daughter from her husband's previous marriage. The neo-Darwinists even argue that it is "natural" to favour your own genes over those of a stranger.
At a storytelling level, Cinderella always works, because we love the idea of a person who has been ignored and humiliated overcoming adversity and winning her rightful place in the world - and in love. Writers have plundered the Cinderella theme from Jane Eyre to Pretty Woman.
Bettelheim claims that this is an important journey for children to understand: that life will bring adversity, and there will be struggles. He even maintains that it is cruel to teach children the genuinely mendacious fairytale which consumerism tends to impart: that life is just about pleasure, reward and comfort.
The story is open to any amount of interpretations, to be sure. Men, for example, are strangely passive in the Cinderella story: it's the women who have the power - the evil stepmother on the one hand, the good fairy godmother on the other.
The German Grimm brothers presented a darker portrait of Cinderella - but also made her more active about her own choices - while the French Charles Perrault rendered the fable courtly and prettier. He introduced the glass slipper, which it has been claimed is a mistranslated "verre" - glass - for "vair" - calf fur. But the folklorists say that Perrault deliberately introduced the glass slipper.
Warner writes that the glass slipper symbolises Cinderella's journey from hairy animal to the social arena of sparkle, light and crystal.
Maybe so: but Lily James found it impossible to walk, let alone flee, in the glass slippers that were especially constructed for her - four pairs, each pair costing £40,000 to make - so in the end director Branagh did the slipper sequence with computer-generated images.
We all like the idea, I think, that Cinderella is loved for who she is, even when in rags, and the step-sisters rebuffed for their false ideas that pretensions can substitute for character and virtue.
The world's most popular fairytale is also one of the most uplifting.