Mind-body dualism is the theory that mind and body are separate kinds of entities. Professional philosophers distinguish various types of dualism, notably property dualism and substance dualism.
Property dualism states that while mind emerges from matter, entities can have mental properties that cannot be reduced to physical properties. This position seems related to the more general issue of emergent properties and how they are related to the original properties of a system.
Substance dualism states that mind has a substance or essence different from what physical entities have, something like vitalism for the mind. It is the most familiar dualism hypothesis, and it has had a long history. Common conceptions of soul feature substance dualism, and in some versions, mind can separate from body and keep on operating. This separation is a common "explanation" of the afterlife, ghosts and out-of-body experiences.
Dualists have several hypotheses on how mind interacts with body:
- Interactionism: René Descartes had famously proposed that the site of interaction is the pineal gland, a part of the brain.
- Parallelism or pre-established harmony: God set up the Universe so that minds are always in sync with their environments. Notably advocated by philosophers Arnold Geulincx and Gottfried Leibniz.
- Occasionalism: God creates the appearance of interaction by intervening where appropriate, even if it means a lot of intervention.
Substance dualism may seem intuitively obvious; mind seems very unlike physical objects, as Descartes himself had noted. However, substance dualism has gotten no support in modern science, which has yielded a large body of results that can reasonably be interpreted as counterevidence. In particular, there is a large body of evidence of localization of brain function and correlations between mind activities and brain activities, even extending to religious and mystical experiences. So a separate mind-substance has become a superfluous hypothesis, much the life-substance or vital force of vitalism.
- Dualism (Stanford Encyclopedia of Philosophy)
- Dualism and Mind [Internet Encyclopedia of Philosophy]
- Ebon Musings: A Ghost in the Machine, a criticism of mind-body dualism featuring a wide range of evidence.
This article was originally at the Beacon Library (now defunct).