This is one of the minor Upaniṣads belonging to the Kṛṣṇa Yajurveda.
It starts with the visit of the sage Sāṅkṛti to Ādityaloka, the world of Āditya or Sun-god, and pleasing him with a laudatory hymn. This hymn has been called ‘cākṣuṣmatī-vidyā.’ The Sun-god who is the deity presiding over light in the external world and the power of sight in the bodies of living beings, declares that whosoever recites this hymn regularly everyday will not be affected by diseases of the eye. Since this Upaniṣad thus begins with a hymn connected with the ‘akṣi’ or the eye, it has been named Akṣi Upaniṣad.
The sage Sāṅkṛti then beseeches Lord Āditya to teach him Brahmavidyā or knowledge of Brahman. This question leads to a fairly long discourse by Āditya on quite a few of the well-known Vedāntic doctrines. A major part of this is devoted to a description of the seven bhūmis or planes of yogic state.
In the first state, the yogi looks upon everything as the one, the unborn, indestructible, eternal Principle. This gradually leads to a natural dissolution of the mind wherein nothing except that one, is experienced. This is yoga. Trying to remain in that state, the yogi performs all actions. He is detached from all the internal mental impressions, but performs all good actions, actions which will not cause agitation in others’ minds. He loves all and speaks words suitable for the time and place. He serves the holy ones in all ways. He is interested in reflecting upon the holy scriptures.
In the second state, the yogi approa-ches people well-versed in the scriptures and learns from them about śrutis (Vedas), smṛtis (secondary scriptures), sadācāra (good conduct) and yogic practices like dhāraṇā (attention) and dhyāna (meditation). He tries to transcend the six evils like pride and greed.
In the third state he fixes his mind on the truths of the scriptures after hearing about them from the ṛṣis in the Vānaprastha stage of life. He observes hard austerities like lying on a bed of stone and roaming in the forests, to develop non-attachment. He develops great detachment to all the things of life—pairs of opposite—taking them as either due to the previous karma or as the will of God.
In the fourth state, the yogi has transcended duality, is established in the advaita or non-dual state of consciousness and hence perceives the world only as a dream.
In the fifth state, even this perception of the world as a dream disappears.
In the sixth state, his mind gets attenuated further, advaitic consciousness becomes stronger, and doubts and bonds disappear. He is, for all practical purposes, a jīvanmukta or ‘one who is liberated even while living.’
The seventh state, which the Upaniṣad call s as ‘videhamukti’ is characterized by total freedom from all bonds, rules and regulations and deep constant experience of the highest identity with Paramātman or Vāsudeva, the Supreme God.
See also UPANIṢADS.