In normal everyday usage, "I" embodies the primordial error, a misperception of who you are, an illusory sense of identity. This is the ego. The illusory sense of self is what Albert Einstein, who had deep insights not only into the reality of space an time, but also into human nature, referred to as "an optical illusion of consciousness.
Eckhart Tolle, A New Earth: Awakening to Your Life's Purpose
albert-eintsein, consciousness, ego