The “self” does not exist within a vacuum. For an entity to be considered to have a sense of self, it requires certain characteristics and attributes. This paper investigates these “structures” of the sense of self in detail, which range from a unified consciousness to self-awareness to personal identity. The paper details how each attribute and characteristic is strictly necessary for an entity to be classified as having a self, and how the five structures detailed within may be used as (...) a guide for categorising and classifying entities as having selfhood or not (or any point along the spectrum between these). The five structures do not represent a theory of selfhood, but rather a meta-theory on the potential emergence and classification of the self. (shrink)