Beginning of Essay
Sri Shankaracharya and some of his modern followers take Monism or Atmaikya, and Absolutism or nirguNa-brahmavaada to be the central theme of Upanishads. Consequently, Idealism or the world being merely a projection, which is unreal, is also taken to be a tenet ....

Middle of Essay
.... the Upanishads delineating the glory of God, the process of creation, prescribing different methods of upaasanaa, Eschatology, recommending meditation, devotion etc. have to be relegated to a secondary position, as they are essentially dealing with the machinations of the unreal Avidya, which vanishes into "nothing," when the soul is liberated and discovers its identity with the formless and attributeless Brahman. In other words, much of Upanishadic texts are worthless and untrue in the domain of the final reality. On the other hand, a few passages are elevated to decisive importance, as they can be interpreted, in a limited sense, to convey Monism. ....