Bound up with reflection of Pure-consciousness, the Nescience, which hides the Atman and is the cause of both the gross and the subtle bodies, is called the AVYAAKRTA or undifferentiated. This is the causal body of the Atman. This is neither existent nor non-existent, nor even both existent and non-existent; neither different from, nor identical with, nor both different from and identical with, the Atman. This Nescience is neither composite, nor non composite, nor both composite and non- composite, but removable by the knowledge of the identity of Brahman and the Atman alone. When all thoughts cease and the determinative intellect, too, lapses into its causal condition, the state of deep sleep appears. The personality appropriating these two, i.e., the causal-body and the deep- sleep state is described as PRAJNA. These three (the causal-body Nescience, the deep-sleep state and the PRAJNA) are symbolised by the last letter M in AUM.