The topic of the presented article is to show the relation between two dimensions of the reality, one of them is denoted by the term akṣarātman, and the other by the term vijānātman. The term vijānātman occurs only twice in the classical Upanishads. We can find it in the Praśna. That analysis is carried out by the using the hermeneutical methodology. All consideration are based on the main text of Praśna with some additional remarks to the other texts belonging to the line of Atharvaveda, to the Muṇḍaka and to the Māṇḍukya. The leading idea of the Praśna and Muṇḍaka, they are according to the Śankara closely related, are the deliberation between parā and aparā vidyā and the special stress which is put on the describing details concerning yogic procedures.
The main aim of that article is to show how the philosophical concepts have been developing. In which way on the base of the introspective experiences have been built upanishadic view of the world and in which way that view had been adopted to advaita thought.