Monism attributes oneness or singleness to a concept, such as to existence. Various kinds of monism can be distinguished:Priority monism states that all existing things go back to a source that is distinct from them; e.g., in Neoplatonism everything is derived from The One. In this view only the One is ontologically basic or prior to everything else. Existence monism posits that, strictly speaking, there exists only a single thing, the universe, which can only be artificially and arbitrarily divided into many things. Substance monism asserts that a variety of existing things can be explained in terms of a single reality or substance. Substance monism posits that only one kind of substance exists, although many things may be made up of this substance, e.g., matter or mind. Dual-aspect monism is the view that the mental and the physical are two aspects of, or perspectives on, the same substance. Neutral monism believes the fundamental nature of reality to be neither mental nor physical; in other words it is "neutral".

Advaita Vedanta is a Hindu-tradition of textual exegesis and philosophy and a Hindu sādhanā, a path of spiritual discipline and experience. In a narrow sense it refers to the scholarly tradition belonging to the orthodox Hindu Vedānta tradition, with works written in Sanskrit, as exemplified by the Vedic scholar and teacher (acharya) Adi Shankara ; in a broader sense it refers to a popular medieval and modern syncretic tradition, blending Vedānta with Yoga and other traditions and producing works in vernacular.