Vedanta(meaning literally the end portion of the Vedas) is a branch of Hindu philosophy which focusses on the reading, and analytically interpreting the ancient Vedic writings, especially the Aranyakas and Upanishads. Vedanta is the essence of the Vedas. Various branches of Vedanta exist, each branch choosing to interpret the codified scriptures in its own way. The most important and popular Vedantic branch is the Advaita (ad- not, dwaita- two; meaning non-duality). This branch was popularized by the Hindu philosopher Shankara. (c. 800 AD).
In Advaita, the universe is a singular entity, and the divisions people see between discrete objects in the world are results of ignorance of the true nature of reality. This true nature, Shankara claimed, is identical with Brahman, which/who transcends time and space. While in this ignorant state, a being will remain trapped in the illusions of the world. Thus, the being is reincarnated over and over, and experiences pain and pleasure as the results of his karma. (see reincarnation, karma)
Eventually, Advaita teaches, each person will discover their true as being one with Brahman, and will achieve moksha--release from endless cycles of reincarnation--and perfect oneness with all things. (see Nirvana).
Vedanta has influenced modern science enormously. Schrödinger was a Vedantist, and he claimed to have been inspired by it in his discovery of quantum theory. According to his biographer Walter Moore, there is a clear continuity between Schrödinger’s understanding of Vedānta and his research: "The unity and continuity of Vedanta are reflected in the unity and continuity of wave mechanics. In 1925, the world view of physics was a model of a great machine composed of separable interacting material particles. During the next few years, Schrödinger and Heisenberg and their followers created a universe based on superimposed inseparable waves of probability amplitudes. This new view would be entirely consistent with the Vedantic concept of All in One."
The non-duality of Advaita Vedanta finds a close parallel in some types of Western philosophical thought, especially the ones that challenge the Cartesian division into subject and object or the polarities of Structuralism. Poststructuralism and Deconstruction may be mentioned in particular. The phrase "Tat Tvam Asi"- meaning "You are that" essentialises this train of thought.