the "physically disabled child" is a stock character from Victorian literature
Dickens uses Tim to provoke sympathy
Tim is an embodiment of the surplus population
In Victorian England, a person's value is directly linked to what they physically contribute to society
Ghost remains Scrooge that he can play a role in the Cratchit's poverty + Tim's health
Dickens puts forth a poignant criticism of the unfeeling members in the upper class - designed to undermine their prejudice + awaken readers to harsh realities of poverty