The Upanishads describe the universe, and the human experience, as an interplay of Purusha (the eternal) and Prakṛti (material world). The former manifests itself as Ātman, and the latter as Māyā. The Upanishads refer to the knowledge of Atman as “true knowledge” (Vidya), and the knowledge of Maya as “not true knowledge” (Avidya). Upanishads describe Maya as “the tendency to imagine something where it does not exist, for example, atman with the body”. To the Upanishads, knowledge includes empirical knowledge and spiritual knowledge, complete knowing necessarily includes understanding the hidden principles that work, the realization of the soul of things.
The term Maya has been translated as ‘illusion,’ but then it does not concern normal illusion. Here ‘illusion’ does not mean that the world is not real and simply a figment of the human imagination. Maya means that the world is not as it seems; the world that one experiences is misleading as far as its true nature is concerned.