The Upanishad has spoken of the sleep state at length. This has several purposes?
1. To reiterate that the objective world does not have a permanent reality.
2. To demonstrate that the subject alone remains as the non-dual reality in the sleep state and therefore in all the states.
3. To prove that the sleep state, being non-dual, gives the greatest bliss to the subject consciousness.
4. To prove to the subject-enquirer that bliss is obtained not from objects but on the contrary, in the absence of objects.
5. To prove that duality is samsara, misery and non-duality is liberation, bliss.
6. To give to the Sadhaka a? Preview? a foretaste, of the liberated state.
Brihadaranyaka Upanishad 4.3.22 alludes to this experience: ~ (In this state a father is no father, a mother no mother, Gods no Gods, the Vedas no Vedas. In this state, a thief is no thief, the killer of a noble Brahmana no killer, a monk no monk, a hermit no hermit. This form of his is untouched by good work and untouched by evil work, for he is then beyond all the woes of his intellect. : ~ Santthosh Kumaar
