If one asleep desires no desire whatsoever, sees no dream whatsoever, that is deep sleep (suṣupta). The deep-sleep state (suṣupta-sthāna), unified (ekī-bhūta), just (eva) a cognition-mass (prajñāna-ghana), consisting of bliss (ānanda-maya), enjoying bliss (ānanda-bhuj), whose mouth is thought (cetas-), the Cognitional (prājña), is the third fourth.

In plain words: The third state is deep, dreamless sleep, when we want nothing and see no dreams. Here awareness is gathered into one, peaceful and full of bliss. This self is called Prajna, the knowing one.