When I was six years old, I watched an old Twilight Zone while I was home sick with the flu. In this particular episode, the main character was convinced that he was a figment of another person's dream. So, whenever the person who was dreaming woke up, he was afraid that he would cease to exist. Everyone thought he was crazy, and his wife eventually got him to see a therapist. Eventually, he figured that he was just being crazy, and he went on with his life. The episode ended with his wife waking up as young child. She had dreamed she was grown up, married, and had kids. The main character of the episode was just a figment of her dream.
This really freaked me out. It made me wonder whether I was actually real or not. The worst part of it was I felt that I could really never know whether or not I existed. This was a thought that disturbed for most of my childhood. As I got older, I found that I wasn't the first person who had this thought.
Rene Descartes was a French philosopher and mathematician from 1600s who struggled with this as well. He wrote "Meditations" on the subject, and this work soothed my adolescent anxiety of the state of my existence.
So, to quote the great Descartes, "I think, therefore I am."
