Māyā pre-exists and co-exists with Brahman – the Ultimate Principle, Consciousness. Maya is perceived reality, one that does not reveal the hidden principles, the true reality. Maya is unconscious, Atman is conscious. Maya is the literal, Brahman is the figurative "Upādāna" – the principle, the cause. Maya is born, changes, evolves, dies with time, from circumstances, due to invisible principles of nature, state the Upanishads. Atman-Brahman is eternal, unchanging, invisible principle, unaffected absolute and resplendent consciousness. Maya concept in the Upanishads, states Archibald Gough, is "the indifferent aggregate of all the possibilities of emanatory or derived existences, pre-existing with Brahman", just like the possibility of a future tree pre-exists in the seed of the tree.