Identities are interfaces. They mediate between your interiority and the outside world. Each identity provides a set of affordances—things they allow you to do. If you have access to the identity “cop,” you can do and say things that others can’t. 

When you create a pseudonym, you can give yourself access to affordances that you lack—like the character I played as a kid which gave me the affordance to write in public. If you use those affordances in a way that is true to your spontaneous reactions behind the mask, you are authentic. Often more so than when playing “yourself.”

In small pseudonymous internet forums, for example, people are typically more colorful and individually distinct than in places where people use their offline identities—because they don’t have to think about their careers or what their neighbors will say about them.