Reality is experience, and there is a conscious background of it - the Self, the experiencer, or the consciousness. There is no separation between the experience and the experiencer. Although, there is an illusion of separation created by the mind, which divides the wholeness of the reality into multiple kinds of experiences. It also creates the division of the experience and the experiencer. When we see through this illusion, we find that the Self, and the reality are one, and identical. This is the greatest realization a human can have.