Sophie's World presents the history of philosophy in the form of a novel. A young girl learns about life and philosophy. One day a few weeks before her fifteenth birthday Norwegian schoolgirl Sophie Amundsen looks inside her mailbox and finds a mysterious letter addressed to her. Opening it, she discovers a single piece of paper with two questions written on it: Who are you? And where does the world come from? Sophie is surprised and intrigued and begins to ponder these questions, first with frustration at their apparent childishness and then with a growing interest. Soon the first letter is followed by more communication from this mysterious correspondent, this time in the form of a whole chapter from a book on introductory philosophy. Strangest of all, the book seems to be written specifically to her. .
Soon Sophie finds herself taking a complete course in philosophy from an anonymous philosopher. Then, Sophie and the philosopher finally meet and he reveals his Secret Purpose to her. Suddenly, Sophie's whole world is turned upside-down and the fun really begins. .
The teenage girl, Sophie leans so much from the philosophy that is given about each philosopher from long ago with each of the lessons that she is given from her teacher/philosopher, Alberto. Sophie learns about medieval philosophy while being lectured by a monk in an ancient church, and she learns about Jean-Paul Sartre and Simone de Beauvoir in a French cafe. It all begins with a quotation from Goethe: "He who cannot draw on three thousand years is living from hand to mouth." Could the world have come from nothing? It all seemed so illogical until Democritus invented the most ingenious toy in the world. Next we see Socrates standing in front of a market stall packed with various goods. "What a wonderful number of things I have no use for." We learn about Plato and his theories about the existence of an ideal world of which we see only the dim reflection.