"The Varaha Upanishad (Part IV) refers to the Bhumika ('stage of development of wisdom') which is of the form of pranava (Aum or Om) as formed of or divided into – akāra, ukāra, makāra and ardhmātra, which is on account of the difference of sthula ('gross'), sukshama ('subtle'), bija ('seed' or 'causal') and sakshi ('witness') whose avasthas ('states') are – 'waking', 'dreaming', 'dream-less sleep' and 'turiya'. Sakshi which is 'turiya' is the essence.[7]” -