The story is full of mysteries. Who is Alberto Knox, the philosophy teacher? Why would a UN major send his daughter Hilde postcards by way of Sophie, who doesn't know either of them? How do Hilde's scarf and other objects find their way into Sophie's world?
Originally written in Norwegian, Sophie's World has been translated into 54 languages. There is a little known but surprisingly faithful and good movie adaptation made in the late 1990s. A computer game was also based on the novel.
The book is both a mystery novel and a fun philosophy course in itself, so it is heavily recommended as an introduction or refresher to philosophy, for both children (not too young, of course) and adults.
Spiritualized's Ladies and Gentlemen We Are Floating in Space is named after a line from it.
This novel contains the following tropes:
- Arc Words: "Happy birthday, Hilde!" At one point in the story these words become part of a Wham Line.
- Author Avatar: Alberto Knox, for Major Albert Knag.
- Conversational Troping: Sophie and Alberto talk about almost all the Philosophy Tropes on the list. They also talk about some Psychology Tropes.
- Disproportionate Retribution: From a certain point of view, Hilde's prank on her father can be considered this. All he did, when it comes down to it, was write a book for her in which the main characters discovered they were fictional and weren't happy about it. However, you have to admit he was sort of asking for it, by having Sophie and Alberto go on about how horrible it is to be helpless tools of their author and repeatedly asking Hilde for help in plotting against him.
- Fake Crossover: Late in the story, all kinds of famous fictional characters, including Alice Liddell and Winnie the Pooh, show up for brief cameos. This is, however, after Sophie has discovered that she herself is a fictional character, and now her author is just messing around and throwing all kinds of surreal stuff into the story, so it can hardly be said to be canon for any of the other characters.
- Still, the ending reveals that all fictional characters are, in a sense, real, and can and do meet each other outside their stories, so the "fake" part might get a little blurry there.
- Framing Device: All of Sophie's world is in fact imaginary and conjured up by the major to give to his daughter Hilde as a birthday present by way of a book.
- Gainax Ending: Your head will be spinning.
- Hand Wave: "A bagatelle, Sophie."
- Insignificant Little Blue Planet: Hilde and Albert's conversation at the end.
- Instructional Dialogue: Most of the novel is taken up by a dialogue that summarizes the entirety of Western philosophy from the Pre-Socratics to Sartre.
- Intergenerational Friendship: Sophie and Alberto, eventually.
- Little Miss Snarker: Sophie.
- Meaningful Name: Lampshaded with Sophie, Alberto, and Hilde.
- Medium Awareness: Alberto. He's aware that he and Sophie are characters in the major's book, at points even going as far as saying "Next chapter!" and telling Sophie not to talk to him so he can work on his plan while the book isn't focused on him.
- Meta Fiction: Once Sophie Notices The Fourth Wall, it completely breaks down and her world becomes no more rule bound than a dream.
- Mind Screw: The book can drift into this occasionally. Most often when the book is discussing philosophers who strongly question our assumptions about reality.
- Leaning on the Fourth Wall: Alberto frequently does this, such as describing Berkeley's view that "we exist only in the mind of God". This takes on a new meaning when it turns out Sophie's world is just a product of the imagination of Hilde's father.
- Nested Story Reveal: Sophie's world exists only as an elaborate literary ruse of a major to show his daughter the value of philosophy as the antidote to war and violence.
- Platonic Cave: Early into the course, Alberto touches upon the Platonic Cave, describing the world as a cave with shadows on the wall, philosophy the tool in which to free oneself from the cave with any attempt to encourage the same in others met with hostility. Alberto was able to deduce that his entire world was fictional and, when explaining this to the guests at Sophie's philosophy party, is met with threats of violence from the parents attending.
- Recursive Reality: The major's book, the content of which is actually identical to the actual book up until the point where Hilde comes in.
- Show Within a Show: But the reader is introduced to the inner show first.
- Significant Birth Date: June the fifteenth, which is both Sophie and Hilde's birthday.
- Trapped on the Astral Plane: A variation on this, in which all fictional characters, including Sophie herself exist in a world on top of the "real" one, able to observe real people, but generally not being able to interact with them.
- Trash the Set: A literalute example happens in the last chapter of Sophie's "world" (i.e., the one made up by the major).
- Walking the Earth and Walking Entire Eras of Human History To Observe Various Human Philosophies and Ideologies