Monism[1] is a philosophical position which argues that the variety of existing things can be explained in terms of a single reality or substance.[2] The wide definition states that all existing things go back to a source which is distinct from them.[3] The common, restricted definition implies also a unity of substance and essence.[3]

Contrasting with monism are metaphysical dualism[3][note 1] and metaphysical pluralism.[3][note 2]

The term monism originates in western philosophy,[4] but has also been applied to religions.


he term Monism was introduced in the 18th century by Christian von Wolff[4] in his work Logic (1728),[5] to designate types of philosophical thought in which the attempt was made to eliminate the dichotomy of body and mind[6] and explain all phenomena by one unifying principle, or as manifestations of a single substance.[4]

The body-mind dichotomy in philosophy examines the relationship between mind and matter, and in particular the relationship between consciousness and the brain. The problem was addressed by René Descartes in the 17th century, resulting in Cartesian dualism, and by pre-Aristotelian philosophers,[7][8] in Avicennian philosophy,[9] and in earlier Asian and more specifically Indian traditions.

It was later also applied to the theory of absolute identity set forth by Hegel and Schelling.[10] Thereafter the term was more broadly used, for any theory postulating a unifying principle.[10] The opponent thesis of dualism also was broadened, to include pluralism.[10] According to Urmson, as a result of this extended use, the term is "systematically ambiguous".[10]

According to Jonathan Schaffer, monism has lost popularity due to the emergence of Analytic philosophy in the early twentieth century, which revolted against the neo-Hegelians. Carnap and Ayer, who were strong proponents of positivism, "ridiculed the whole question as incoherent mysticism".[11]

The mind-body problem has reemerged in social psychology and related fields, with the interest in mind-body interaction[12] and the rejection of Cartesian mind-body dualism in the identity thesis, a modern form of monism.[13] Monism is also still relevant to the philosophy of mind,[10] where various positions are defended.[14][15]


There are two sorts of definitions for monism:

  1. The wide definition: a philosophy is monistic if it postulates unity of origin of all things; all existing things go back to a source which is distinct from them.[3]
  2. The restricted definition: this requires not only unity of origin but also unity of substance and essence.[3]

Three basic types of monism can be discerned:[10]

  1. Substantial monism, "the view that the apparent plurality of substances is due to different states or appearances of a single substance"[10]
  2. Attributive monism, "the view that whatever the number of substances, they are of a single ultimate kind"[10]
  3. Partial monism, "within a given realm of being (however many there may be) there is only one substance"[10]

Contrasting with monism are:

Although the term "monism" originated in western philosophy to typify positions in the mind-body problem, it has also been used to typify religious traditions. In modern Hinduism, the term "absolute monism" is being used for Advaita Vedanta.[16][17]