That's in the normal sense of human existence.
But according to one school of Hinduism (Bhagwan Ramana Maharshi) only when our mind stops fully, we can grasp our true existence. At that state "I" totally disappears. You realize your true existence as Atman. You become the knower of all. You become one with Brahman (God).
This state is stated as "Aham Brahmasmi" (I am Brahman) in Hindu scripture Upanishad. In Bible, it is said "I am that I am".