Self

Since nothing we experience is constant, why do we even have a notion of "self"—something that is supposed to be constant in our experience—to begin with? If we think about the origins of our notions of self, it seems plausible to assume that it has something to do with what obeys our will. An infant is aware of many things in the world, including sensations of his own body and mind. He begins to differentiate self from nonself in this total field of experience by noting that some things obey his will—his hands and feet, his voice and body—while others, like the sun and moon, his parents, the spoon on the table, do not obey his will except intermittently and always through the mediation of actions of his body or mind. Some things he controls directly and consistently: these come to be considered "self." Some things he controls only when other things cooperate in just the right way, and even then always only with the participation of the first class of things: these come to be considered "nonself."

---Brook A. Ziporyn, in Emptiness and Omnipresence---