Already in the Vedic Period, the question was raised regarding the unity and foundation underlying the multiplicity of manifestations of the gods and of the universe: this led to a relativization of the Vedic gods and a crisis in the Vedic worldview.
Criticism of the Brahmins, with their more and more complex teachings and their many privileges, became increasingly vocal.
Religious reformers (Buddha, Mahavira) appeared on the scene and challenged the authority of the Vedas and the Brahmins.
Late-Vedic texts in the Upanishads pose the question about the foundation
and centre of the human being and of the world. One of the central answers
was: the centre of the human being (atman), the “soul”, is identical
with the foundation of the universe
(brahman).
