I feel that the writers of these posts cannot have read all of the books. It is made very clear, in The Last Battle, the final book in the series, that it was not adulthood or femininity that barred Susan from Narnia. Adult Susan was not allowed back into Narnia because she stopped believing that Narnia existed. She chose to believe that all her and her siblings' adventures in Narnia were imaginary games.
"Sir," said Tirian, when he had greeted all these. "If I have read the chronicle aright, there should be another. Has not your Majesty two sisters? Where is Queen Susan?"
"My sister Susan," answered Peter shortly and gravely, "is no longer a friend of Narnia." "Yes," said Eustace, "and whenever you've tried to get her to come and talk about Narnia or do anything about Narnia, she says, 'What wonderful memories you have! Fancy your still thinking about all those funny games we used to play when we were children.'"
"Oh Susan!" said Jill. "She's interested in nothing nowadays except nylons and lipstick and invitations. She always was a jolly sight too keen on being grown-up."
"Grown-up, indeed," said the Lady Polly. "I wish she would grow up. She wasted all her school time wanting to be the age she is now, and she'll waste all the rest of her life trying to stay that age. Her whole idea is to race on to the silliest time of one's life as quick as she can and then stop there as long as she can."
(From The Last Battle, by C.S. Lewis, 1956, pp. 127–128.)
Narnia did not wrong Susan. Susan wronged Narnia. She helped to save Narnia, became a hero there, grew up there, made friends there, became "Queen Susan the Fair" — and then, when she became an adult in our world, she chose to forget that Narnia had ever been real.
Reading the above-quoted passage in The Last Battle is shocking and horrifying. How could Susan forget something so important — something from her own past?! She was a good, kind, compassionate person — when did she become so awful?! How could she do this to herself, to her siblings, and to Narnia itself?
It is meant to be shocking. It is meant to sting. The author, C.S. Lewis, did not turn on Susan and decide to punish her for growing up, for becoming feminine, for a lack of faith or loyalty, for anything; rather, Susan's devastating betrayal is meant to make a point about how the people we love and trust in childhood can change beyond recognition, and forsake their bonds with us; — bonds that we thought would last forever.
I think that many readers do not understand how Susan could change so suddenly, nor why she would, and thus assume that the author is at fault: that he decided to defame her character — as though the reader understands the character better than her creator does. Their reasoning seems to be, "Susan would never do that: it must be C.S. Lewis's fault. He has told his story incorrectly. He has wronged a character that he created."
But we are not meant to understand why Susan left. That is the entire point. Susan's betrayal is supposed to be incomprehensible.
Why?
Because that's how it feels when someone betrays you like that.
I have had a "Susan" in my life.
I was shocked and hurt when I read The Last Battle for the first time and found that Susan had betrayed her siblings, her past, her queendom, her friends. Every time I have re-read The Chronicles Of Narnia, that passage has made my soul writhe at the wrongness of Susan's behaviour. And now, having had my own "Susan" behave almost identically to Susan Pevensie, I understand why Lewis did what he did.
He knew exactly what he was doing.
(My story 'The Leaving Of Princess Laellinon' (published in Three Short Fairytales) was inspired by the behaviour of my "Susan", and the grief and confusion of those left behind.)
Susan Pevensie is not a victim of C.S. Lewis's writing, nor of Narnia's "unfair" rules, or anything like that. If Susan is a victim, it could be argued that she is a victim of our society, not Narnia's: our society that condemns childlike belief in goodness and wonder, nobility and honour, faith and the greater good; our society that encourages superficiality, conformity, materialism, gender stereotypes, and a shallow sense of what it means to be a grown-up. Our society, which tells young people that they must outgrow fairytales and "face facts", resigning themselves to a cynical existence in which doing good and striving for a noble, joyful, virtuous life are considered, at best, childish and immature or self-righteous and moralising.
But primarily Susan is a victim of her own lack of inner strength and faith. She could have chosen to keep believing: all of her siblings did, despite being under the same societal pressures as Susan was. She did not have to turn her back on Narnia. She chose to do so.
Just as my "Susan" did.
If you find that Susan's betrayal shatters your understanding of her character, then congratulations: you understand the pain of the remaining Pevensie siblings.
May you never have a "Susan" in your life. May you never be betrayed thus. But don't blame C.S. Lewis for defaming Susan's character: Susan did that by herself. All Lewis did was use Susan to make a point about something that real people do — just as he did with every other character in The Chronicles Of Narnia.
