The early Vedic Upaniṣads call this unified and imperishable world soul
brahman or
ātman, the former applying more typically to the godhead and the latter signifying the correlative divine "self" residing at the deepest level of one's person. The theistic Upaniṣads teach that this
brahman or
ātman is a single deity known generically as Īśv Īśa (Lord) living deep within one's being and identified particularly as Śiva, Viṣṇu, or the Goddess by particular sectarian communities.
While they explicitly or implicitly admit the difficulties of comprehending a hidden reality that either transcends or simply cannot be known through the structures of time, space, and causation, the Upaniṣads hold that through disciplined practices of meditation and the cultivation of extraordinary knowledge, it can in fact be discerned. Such discernment releases one from the apparent cycles of life and death caused by one's ignorance of the fact that the essential self does not die. Thus, Upaniṣadic religious anthropologies, theologies, and soteriologies all revolve around a key lesson that appears ubiquitously but that might well be characterized by the Adhyātma Upaniṣad's assertion that "he is a free person who through insight sees no distinction between his own self and brahman, and between brahman and the universe" and the Kaṭha Upaniṣad's proclamation that, having comprehended this identity, "one is released from the jaws of death" (3.5).
