What is "nondualism"

n. The belief that dualism or dichotomy are illusory phenomena, that things such as mind and body may remain distinct while not actually being separate.

Nondualism, also called non-duality, means "not two" or "one undivided without a second". It is a term and concept used to define various strands of religious and spiritual thought. It is found in a variety of Asian religious traditions and modern western spirituality, but with a variety of meanings and uses. The term may refer to:

• Advaya, the nonduality of conventional and ultimate truth in Madhyamaka Buddhism. In Buddhist Madhyamaka it means that there is no absolute, transcendent reality beyond our everyday reality, and while things exist, they are ultimately "empty" of any existence on their own. In Yogacara, it refers to the idea of nondualism of cognition and that which is cognized;
• Advaita, which states that all of the universe is one essential reality, and that all facets and aspects of the universe are ultimately an expression or appearance of that one reality. This is an ontological approach to nondualism, and asserts non-difference between Ātman (soul) and Brahman (the Absolute). This idea is best known from Advaita Vedanta, but also found in other Hindu traditions such as the Kashmir Shaivism, popular teachers like Ramana Maharshi and Nisargadatta Maharaj;
• "Nondual consciousness", the non-duality of subject and object; this can be found in modern spirituality.

The nondualism idea developed in the Vedic, post-Vedic Hindu and the Buddhist traditions. The oldest traces of nondualism in Indian thought is found as Advaita in the Brihadaranyaka Upanishad, as well as other pre-Buddhist Upanishads such as the Chandogya Upanishad. The Buddhist tradition added the teachings of śūnyatā; the two truths doctrine, the nonduality of the absolute and the relative truth, and the Yogachara notion of "mind/thought only" (citta-matra) or "representation-only" ( vijñaptimātra). Vijñapti-mātra and the two truths doctrine, coupled with the concept of Buddha-nature, have also been influential concepts in the subsequent development of Mahayana Buddhism, not only in India, but also in China and Tibet, most notably the Chán (Zen) and Dzogchen traditions. In Hinduism, nondualism has more commonly become associated with the Advaita Vedanta tradition of Adi Shankara.

The western origins are situated within Western esotericism, especially Swedenborgianism, Unitarianism, Transcendentalism and the idea of religious experience as a valid means of knowledge of a transcendental reality. Universalism and Perennialism are another important strand of thought, as reflected in various strands of modern spirituality, New Age and Neo-Advaita.