Mind-body dualism

Mind–body dualism is a set of philosophical positions holding that mental phenomena are non-physical, or that the mind and the body are distinct and separable. It belongs to the mind–body problem and is contrasted with positions such as physicalism and monism.

The idea has ancient roots. Plato regarded the soul as independent of the body and believed in its migration to new bodies. Aristotle understood the soul as the form of a living organism: its nutritive and perceptive parts perish with the body, while an intellective part remains. The modern formulation, however, is chiefly associated with René Descartes, who in the seventeenth century argued that the mind is a non-physical, non-spatial substance, identified with consciousness and self-awareness and distinct from the brain as the seat of intelligence. He was the first Western philosopher documented to state the mind–body problem in roughly the form it still takes today.

Dualism comes in several versions. Substance dualism holds that mind and matter are fundamentally different kinds of things, and many of its defenders accept that the two can causally interact. Property dualism locates the difference in properties rather than substances: consciousness emerges when matter is organised in a particular way, which sometimes places it within emergentism or non-reductive physicalism. Other approaches, such as Thomistic or hylomorphic dualism, reject the idea of two separate substances and speak instead of one substance with two principles.

For centuries the concept served as the dominant paradigm in biomedicine. Advances in neuroscience, which show how mental life depends on the brain, have strengthened physicalist positions. The debate continues between those who hold consciousness to be irreducible to physical processes and those who think scientific explanation should suffice.