As Descartes succinctly wrote, "Cognito, ergo sum."
That being said, I am a blank page. My actions, thoughts, and character qualities are the words that fill the blank page, and define who I am for myself and those readers of my life.
My page is dynamic; others have a page that is static.
My page is introspective.
Others have a page that cacophonous in its language and message. Thus, the individual who wrote that page has actions and thoughts that are in accordance with their (assumably) cavalier lifestyle. This is the person who makes sure you know how much they make, how many chicks (or dudes) they have done, how hugly expensive and wonderful thier car is, etc.
Everyday we write who we are. If you take the time to read a person's actions and choices, it can be quite a revealing story about that person.