I think that there is a difference between identity and label. A label (like Nathan suggested)such as obesity does not define someone's identity. How could obesity make a person's identity? An obese person could be sweet, intelligent, compassionate, hard-working person. Those qualities make the identity.

Identities aren't given labels. Identities are something that we grasp onto - just like peer pressure. When you are a teenager trying to find your own identity, peer pressure is strong and you tend to go along with the crowd thus "losing" your own identity. It takes a strong person to find one identity and truly stand for it. Environmentalists whose identities are against logging, who live in the trees as a means of protest - that is their identity. Although we may label them a tree-hugger, it isn't their identity.

I think that what the passage was talking about is that people tend to grasp at several different identities and never look beyond any of them. If I were to examine myself, I have a professional (work) identity, I have a parental identity and I have a wife identity. All are different aspects of me. But instead of holding steadfastedly to anyone of those, I have to look beyond them to mesh them all into who I am as a person.

Or perhaps I could just ramble on about nothing!