Crucial to this story is the idea that individual actions can transform the future, for good or ill. Supernatural events—the multiple appearances of ghosts—break into Scrooge's life, causing him to change his behavior.
The ghosts can be seen as metaphors for memory, empathy and the imagination. As Scrooge remembers the better self of his past and the people who touched him emotionally through the ghost of Christmas Past, his heart softens, opening him to emotions he had shut down. As he regains the capacity to feel, he views the present through new, more compassionate eyes. With the help of the ghost of Christmas Future, he can imagine the bleak scenario of Tiny Tim's death. He can also imagine his own death being celebrated rather than mourned.
This new—or old—way of seeing leads Scrooge to take control of changing his destiny, as is illustrated at the end of the novel: Scrooge makes the conscious choice to act generously and benevolently, using his wealth to improve the general good, and more particularly, the circumstances of the Cratchit family. Scrooge's redemption leads to changed destinies: so can anybody's redemption change destinies. This hopeful message is a key to the book's popularity. It is also typical of Dickens' belief that touching individual hearts and motivating people to acts of kindness and compassion can transform society.