In its most basic meaning, dualism is (1) the division of something conceptually into two opposed or contrasted aspects, or the state of being so divided, or (2) the quality or condition of being dual; i.e., duality. Some dualisms include that of mind and body, or of mind and matter.

Moral dualism is the belief of the great complement of, or conflict between, the benevolent and the malevolent; i.e., good and evil. Christian dualism refers to the belief that God and creation are distinct, but interrelated through an indivisible bond. Émile Durkheim attributed to humankind a dual nature, which is made up of the body (individual) and the soul (social). The Dvaita Vedanta school of Indian philosophy espouses a dualism between God and the universe by theorizing the existence of two separate realities. In a Nenets myth of the Samoyed (Siberian) peoples, Num and Nga collaborate and compete with each other, creating land.

The most common usage of the term and the most relevant to the human environment and habitat refers to the belief in a dualism between man and nature. This dualism, rooted in Judeo-Christian thought, expressed in colonial dominance over the natural world and those who dwell in it. Consolidated in 16^th and 17^th century Europe, social thought espoused by such philosophers as René Descartes and Immanuel Kant constructed human/nature an enduring mental divide between human and nature, justifying human alienation from, and hierarchical dominance over the natural world.

The consequences of population growth and industrialization’s profligate exploitation of land and nature over time, including climate change, have inspired thinking beyond the humankind/nature dualism to more-integrated visions of the sphere of life upon which humankind’s survival depends. This has led to more-recent calls—some echoing millennia-old indigenous cultures—seeking to operationalize a needed correction to this man-versus-nature dualism as an obsolete dichotomy. An expression of this urgent call is found in the 2022 UN Secretary General’s report on “Harmony with Nature” report [AR] and the General Assembly’s recent eponymous resolution [AR].