To understand what self is, we must first know the purpose of self. Why are there seven billion “selves” on this planet? They are all here for one reason: to learn. To gather experience and wisdom for the whole. The whole can only evolve and grow as each self observes, remembers, acts, and learns.
Just as bees have mandibles, wings, and legs for the sole purpose of gathering pollen, all the properties of self derive from its purpose. To learn, each self must observe experience, remember experience, organize experience (into categories and higher order conclusions called wisdom), and choose mental and physical actions (focusing awareness and deciding what to do).
No learning can happen without engaging each property of the self. No wisdom tradition can find truth through a single aspect of self. As each self learns, the whole becomes god.