Advaita Vedanta holds that ultimate reality is the innermost awareness of the Self: the singular sentience experienced as "I".
Mind, memory, sensation, and world all appear to this awareness. They are known because awareness is present, not the other way around.
This shifts the center of philosophy away from objects and toward the condition that makes any object known at all.
What appears as a separate universe is understood as manifestation within awareness, much as waves appear on water without becoming something other than water.
The Self is not a part of the world. It is the non-objective basis in which the world becomes experience.
The true Self is not identical with the psychological personality. It is not a refined version of personal identity, nor a private interior object.
Vedantic inquiry works by discriminating the changing from the unchanging until the basis of experience stands clear on its own terms.