Types of Samadhi
From AHAM: Daily Message for Transforming the Mind #3344:
Q: It is said that one remaining in nirvikalpa samadhi (natural absorption in Self) for 21 days must necessarily give up the physical body.
M: Samadhi means passing beyond. Non-identification of the body with the Self is a foregone conclusion. There are said to be people who have been immersed in nirvikalpa samadhi for a thousand years or more.
1. Holding onto Reality is samadhi.
2. Holding onto Reality with effort is savikalpa samadhi.
3. Merging into Reality and remaining unaware of the world is nirvikalpa samadhi.
4. Merging in ignorance and remaining unaware of the world is sleep -- the head bows but not in samadhi.
5. Remaining in the primal, pure, natural state without effort is sahaja nirvikalpa samadhi.
"The world is a perpetual change, a continuous, interminable flux. A dependent, unself-conscious, ever-changing world cannot be real…. If the world is a self-existent reality, what prevents it from revealing itself to you in deep sleep?"—Ramana Maharshi