The story begins with the main character, Sophia, returning home from school. In front of her house, she discovers a letter with a message inside it asking Sophie ‘’Who are you?’’ Sophie then gets inside her house and thinks that she doesn’t know who she really is and that she has a limited amount of time to find out who she wants to be.
Inside the house, Sophie finds another letter asking her about the origin of everything and Sophie notes that she can’t answer that question either. Sophie goes to her safe space and then goes to the mailbox where she finds a postcard from her father who claims that he has something for her that will help her grow. The postcard however is not sent to her but to someone else, a girl named Hilde. She then decides that she must solve the three mysteries she is presented with and find the answer to the two questions and find who the mystery girl is.
Sophie goes on with her life but she is no longer as interested in the things that used to make her happy in the past. Then, one day, she returns home to find a three pages letter in the mailbox answering the question What is philosophy?. In the letter there are mentioned several questions philosophy tried to answer and then compares philosophers to detectives who try to answer those questions. She then finds another letter, telling her that she will be thought about philosophy and about the wonders of the world. When Sophie’s mother comes home, Sophie tries to tell her mother about what she learned but she is quickly dismissed and even made fun of.
The next day, Sophie finds both a letter from her father and another letter from the anonymous philosopher that explained to her why mythology appeared and why people believed in Gods in the past. According to him, people needed a way of explaining natural accruing phenomenon and thus they invented Gods that were in their perspective the ones responsible for those phenomenons. The people from those times began offering sacrifices to the Gods thinking that it was the only way they could continue having rain or good crops. When for example there was no rain, the people tried to rationalize this as well through stories. To prove his point, the anonymous philosopher mentions the Norse mythology and the story of Thor and his hammer but also certain aspects of the Greek mythology. The people who gave up their Gods the first were the ones who developed some kind of civilization first and the reason behind this is that they then began to talk about their myths, discuss them and debunk them.
In the next letter she receives, Sophie is asked three questions: Can water turn into wine? How can the earth and water produce a live frog? and Is there a basic substance that everything else is made of?
After thinking about the questions, Sophie thought that it is possible to have a positive answer to those questions. In the next letter, the philosopher presents her the history of philosophy and tells her that the first philosophers were the naturalist ones who tried to explain how an animal can grow from an egg and reached the conclusion that everyone and everything has at its core the same basic element. They were also the first ones to separate religion from philosophy and to exclude the Gods from their theories. Those philosophers also disused the idea of change and the philosophers were torn between the idea that the world changes constantly or that it doesn’t change at all. An important philosopher who reconciled the two points of view was Empedocles who claimed that in nature there are four elements that never change but the way they interact with one another changes constantly.
In her next letter, Sophie is presented with the atom theory that was first proposed by Democritus who claimed that each atom was different and that explains the difference between people. The atoms can also separate and then go on to fuse with other atoms to create something new entirely.
In her next letter, Sophie is asked whether she believes in fate of not and if she believes that humans are punished by different Gods. The writer then goes to write about the Greek society and different myths about people or Gods punished for their deeds. There were however people who were less inclined to believe that wars and illness were the result of unhappy Gods and more the result of bad decisions.
Sophie becomes increasingly more interested in the identity of the anonymous philosopher and while she tries to catch him while dropping off her letters. She sees a man putting a letter in her mailbox one day but in the letter she is warned against trying to find who he is and also reassured that they will meet one day.
The anonymous writer reveals his name and tells Sophie that he is Alberto Knox and that he is sorry that they are not able to meet in person. He also tells her how she must send him letters if she wants to communicate with him. Next, they talk about modesty and if modesty is natural or not. Next, they talk about the philosophy of Athens and about the Sophists in Athens. The sophists tried to find man’s place in the world and they also denied the concept of right or wrong. The most influential philosophers were Socrates and Plato and they were skepticists, questioning everything around them. Socrates was considered dangerous by the government in Athens and he committed suicide to avoid being thrown out of the city.
Next, Sophie receives a VCR tape in which a man introduces himself as being Alberto Knox while standing before the ruins of what he claims to be the Parthenon. Then, Alberto moves to a different location, to a city that looks brand new and claims that two men coming his way are Socrates and Plato. Socrates greets Sophie and then proceeds to ask her a couple of hard questions that are at the base of the sophist philosophy.
One of the questions posed by Socrates is whether a baker can bake 50 identical cookies and after giving it a little bit of thought, Sophie reaches the conclusion that a baker could bake 50 identical cookies if he was to use the same mold.
The next letter Sophie receives is about Plato and how he transcribed Socrates’ ideas that he considered as being important. Then, the distinction between the world of ideas and the real world in which people live is explained. Plato also claimed that the soul is immortal and that when a person dies; the soul travels to the world of ideas where it learns new things before returning to a new body. According to Plato, a person can remember the time he or she spent in the world of idea through contemplation and meditation and that the things a soul learns are never lost, only forgotten. Then, the Allegory of the Cave is presented and how the philosopher plays an important role in discovering what is true and what is an illusion.
The Republic is then presented and how Plato distinguishes between different parts in a society and about the role each part has. He also talked about women and he was among the few who did not considered women as being inferior to men.
The next day, when Sophie returns from school, she discovers a lake and a boat. Sophie takes the boat and she eventually arrives at a small cabin where she finds inside a mirror and a few paintings. When Sophie winks, her reflection winks back at her with both eyes, something that amazes Sophie. She also sees fur on the floor and realizes that it is the cabin where Hermes and Alberto live. Sophie runs when she hears a dog barking but not before grabbing an envelope she finds on the floor. Inside the envelope, there are again three questions, urging Sophie to think about what came first, the idea or the ‘’chicken’’.
When Sophie arrives home, she tells her mother everything she had done in the past few days and about the cabin in the woods. She then writes a letter to Alberto, telling him that she was in his cabin and that she doesn’t think she likes Plato.
In the next letter, Sophie learns about Aristotle who disagreed with Plato and with his belief that there is a perfect world of ideas. Aristotle classified all human beings by taking in consideration their ability to think and he also believed that there is a God who created the world and who was responsible for putting the world in motion. He also believed that there is a right way to live one’s life and that a person must have a balanced live in order to be happy. Aristotle also defined different types of societies and highlighted the idea that every society has the possibility of failing one day.
On the next day, Sophie turns 15 and she discovers a postcard for the same Hilde mentioned in the beginning. She also receives a letter about Hellenism, the philosophical movement that took place between the period in which Aristotle lived and up until the Middle Ages. Alberto mentions the Cynics, the Stoics, the Epicureans , the school of Neo-Platonism and mysticism.
Sophie doesn’t receive letters for a few days and then she has the opportunity to meet with Alberto in person in an abandoned church. The church is an appropriate setting for Sophie’s philosophy lesson because she is thought about the middle Ages and how religion influenced the philosophy during those times. Sophie learns about Thomas Aquinas, Saint Augustine and Hildegard, thinkers who changed what was known until then as philosophy.
Sophie also encounters a series of unexpected events and learns that Hilde is Albert’s daughter and is roughly the same age as her. Albert continues to send letters to Sophie instead of sending them to his daughter and Sophie finds that Albert is in Lebanon and that he plans to return to his family soon. Sophie is also thought about the Renaissance and about the philosophy of humanism. Next she learns about Baroque, the empiricism movement and rationalism and various other movements that were particular to one country or another.
Alberto also teaches Sophie about the Enlightenment and philosophers such as David Hume, John Locke and Spinoza who slowly replaced religion with philosophy.
