# Classification Is Just Classification Properties that make X different from others do not mean those are the essence of X. This is a very simple truth but quite many people confuse them. Especially in algebra related fields. For example, the set of real numbers R is a 1. Complete 2. Ordered 3. Field and these conditions make the set unique up to isomorphism. Then are the conditions the essence of R, which means all other properties are just details? Heck no. Your fingerprint is not your essence.