Ignorance and Want are two street urchin spirits that show up in The Ghost of Christmas Present segment in A Christmas Carol. They initially look timid inside the robes, but then they start snarling at Ebenezer Scrooge, warning him that they are ruthless. The two are also descriptions on what happened to those that became evil and corrupted by the world: Ignorance is a boy who is shown to grow up to become a dangerous thug (similar to Bill Sikes) that ends up imprisoned. Want is a girl who is shown to grow up to become a cackling hag that is thrown into an insane asylum. This segment is a reference to Oliver Twist and Hard Times, two other Charles Dickens novels that were both about social injustice.
Role in the story
After showing Scrooge the joys of the Holiday Season and the living conditions of Bob Cratchit's impoverished family, the Ghost of Christmas Present finally tells Scrooge the peril that poor people will end up in, should Scrooge not change his miserly ways. The ghost shows Scrooge two seemingly timid street urchins who were using the ghost's robes as shelter, and refers to them as Ignorance and Want. It is implied that if people have been impoverished at childhood, they would either die at an early age (like Tiny Tim), or grow up and have a corrupt adulthood (like Ignorance and Want). In some cases (most famously the Artful Dodger and Fagin's gang) impoverished children become juvenile criminals. Only to get Ignorance imprisoned in a cage and get Want strapped into a straitjacket and taken away to the insane asylum.
Earlier in the story, Scrooge mentioned that he supports prisons and workhouses, believing that anyone badly off financially should go there. Should many of them rather die, Scrooge believed that "they had better do it and decrease the surplus population". It was only until Scrooge had feelings for Tiny Tim and the ghost used that very phrase against Scrooge that he had doubts about this belief.
Are there no prisons?
Ignorance behind bars in a cage
Are there no workhouses?
Want in a straitjacket, taken away to The Insane Asylum