Sissy Jupe from the start lights up the cold, fact-based world of the Grandgrinds, Mr. M'Choakumchild, and Coketown. The child of a circus clown, Sissy is the only person in the Gradgrind world, once her father abandons her, who fully embodies imagination, empathy, and common sense. All of this adds up to goodness: she is a central figure of importance because she represents a humane outlook in a world that has gone mad in its reliance on facts and figures and has lost sight of people.
When we first meet Sissy in the utilitarian schoolroom, she is described as being bathed in light, symbolizing that she is lit up by her imaginative center. This foreshadows that she will be a figure of light in the novel:
Sissy, being at the corner of a row on the sunny side, came in for the beginning of a sunbeam . . . the girl was so dark-eyed and dark-haired, that she seemed to receive a deeper and more lustrous colour from the sun, when it shone upon her.
Sissy counters and punctures the utilitarian philosophy of the "greatest good for the greatest number" when she shows empathy for those who are ground up by the system. She stands up for the idea that every life has value. In the classroom, Mr. M'Choakumchild means for his students to think highly of the fact that, out of a million, "only five- and-twenty are starved to death in the streets, in the course of a year," and asks, "What is your remark on that proportion?" Sissy gets in trouble for saying:
And my remark was—for I couldn't think of a better one—that I thought it must be just as hard upon those who were starved, whether the others were a million, or a million million.
She also gets in trouble for saying she reads fairy stories to her father:
"About the Fairies, sir, and the Dwarf, and the Hunchback, and the Genies," she sobbed out; "and about—"
"Hush!" said Mr. Gradgrind, "that is enough. Never breathe a word of such destructive nonsense any more."
Because of her caring nature, Sissy befriends and helps a large number of characters in the novel, showing the positive side of having an imaginative nature. She helps her father before he leaves her and then helps Mrs. Gradgrind. She sides with and supports Louisa against Mr. Gradgrind, and she befriends Rachel. Because Sissy takes a walk with Rachel, they are able to find Stephen.
Sissy illustrates Dickens's idea that imagination and compassion are good character traits, not traits that need to be eradicated.