The document discusses different philosophical perspectives on the concept of self from ancient to modern times. In ancient Greece, the Pre-Socratics viewed the soul or arché as the origin or source that explains changes in the world. Socrates believed that knowing oneself through introspection is key to virtue and happiness. Plato saw the soul as having three parts - rational, spirited, and appetitive - that must be balanced. St. Augustine and St. Thomas Aquinas incorporated Christian theology, viewing humans as having both imperfect bodily and perfect immortal souls. Modern philosophers like Descartes asserted "I think therefore I am" and separated mind and body, while Hume viewed the self as a bundle of perceptions in constant flux. K