Sri Aurobindo
Letters of Sri Aurobindo
Volume III - Part 3
Nirvikalpa Samadhi according to tradition is simply a trance from which one cannot be awakened even by burning or branding – i.e. a trance in which one has gone completely out of the body. In more scientific parlance it is a trance in which there is no formation or movement of the consciousness and one gets lost in a state from which one can bring back no report except that one was in bliss. It is supposed to be a complete absorption in the Sushupti or the Turiya.