Sri Ramana Maharshi says in Talk 524 (Talks with Sri Ramana Maharshi), “You must exist in order that you may think. You may think these thoughts or other thoughts. The thoughts change but not you. Let go the passing thoughts and hold on to the unchanging Self. The thoughts form your bondage. If they are given up, there is release. The bondage is not external.”
Devotee says: But it is not easy to remain without thinking.
Sri Ramana replies: You need not cease thinking. Only think of the root of the thoughts; seek it and find it. The Self shines by itself. When that is found the thoughts cease of their own accord. That is freedom from bondage (Talk 524).
Bhagavan Ramana teaches that any thing that appears and disappears is not you. That which remains always, is you. The Advaitic system of Neti, Neti (not this, not this) is based on that. The aspirant analyzes everything that he or she perceives and says, “I am not the body, I am not the senses, I am not the mind, etc. Whatever can be perceived is not me as I am the one perceiving it.”
Continuing to reflect on this and doing Neti, Neti, (I am not this, I am not this), finally, that subjective pure awareness remains which cannot be denied. The Subject cannot deny It Self. Hence Advaita Vedanta declares that when you firmly reach the pure Subject which is only Awareness, you should abide in that. That You Are. Thou Art That. That I AM!