There are two stages of God realization. One is called sujñeyam, or very easily understood (generally by mental speculation), and the other is called durjñeyam, understood only with difficulty. Paramātmā realization and Brahman realization are considered sujñeyam, but realization of the Supreme Personality of Godhead is durjñeyam. As described here, one attains the ultimate realization of the Personality of Godhead when one gives up the activities of the mind—thinking, feeling and willing—or, in other words, when mental speculation stops. This transcendental realization is above susupti, deep sleep. In our gross conditional stage we perceive things through material experience and remembrance, and in the subtle stage we perceive the world in dreams. The process of vision also involves remembrance and also exists in a subtle form. Above gross experience and dreams is susupti, deep sleep, and when one comes to the completely spiritual platform, transcending deep sleep, he attains trance, viśuddha-sattva, or vasudeva-sattva, in which the Personality of Godhead is revealed.

Ataḥ śrī-kṛṣṇa-nāmādi na bhaved grāhyam indriyaiḥ: [BRS. ataḥ śrī-kṛṣṇa-nāmādi
na bhaved grāhyam indriyaiḥ
sevonmukhe hi jihvādau
svayam eva sphuraty adaḥ