The philosophical issue of how the mind is related to the body, which brings with it what properties, functions and occurrences should be ascribed to each. The problem impinges not only on the philosophy of the mind, but also on the philosophy of psychology. The modern version of the problem is usually depicted as starting with René Descartes (1596-1650), who apparently began to tackle the problem after receiving a letter in 1643 outlining the problem from Princess Elizabeth of Bohemia (1617-1680), the daughter of James I of England. His solution is what is now referred to Cartesian dualism or interactionism: the mind generates mental experiences that are functions of the soul, and because the soul is immaterial, then it does not reside in any part of the body. However, mind and body do interact with each other in the pineal gland, a site probably chosen by Descartes because it is in the center of the head and which for him functioned like a valve allowing vital spirits to flow through the body, thereby enabling soul and body to influence each other. The impact of Descartes solution was revolutionize anatomy, because now dissections could be carried out without fear of retribution from the Church as the soul had been established as a separate entity from the body. Alternative solutions have included the following:
- occasionalism: attributed to Nicolas Malebranche (1638-1715), God is the sole causal agent in how mind and body relate and each is only the occasion, and not the cause, of the other
- psychophysical parallelism: first put forward by Gottfried W. Leibniz (1646-1716), it attempted to avoid any theological overtones as in occasionalism by holding that mental and bodily events occur in separate, but parallel, sequences that are perfectly correlated and in harmony with each other
- epiphenomenalism: put forward in the 19th century and supported by Thomas H. Huxley (1825-1895) as an alternative interactionism and psychophysical parallelism. According to this solution, mental events are effects, never causes, of physical changes in the body and thus epiphenomena of brain processes are like smoke billowing out of a factory chimney to use Huxley’s metaphor
- identity theory or physicalism: a materialistic theory of consciousness in which mental states are identical to brain states. It is akin to the neutral or mental monism of William James (1842-1910) and the double aspect theory of Baruch Spinoza (1632-1677). The former claims that while the mental and the physical are from the same elements, they are in themselves neither mental nor physical but can be analysed in terms of a common underlying reality, sometimes referred to as neutral stuff. The latter contends that the mental and physical are two different aspects of a single substance, a common example being the morning star and the evening star.
See Brain (or encephalon), Consciousness, Dualism, Embodied cognition, Embodiment, Metaphor, Monism, Pineal gland, Quantum mechanics, Vitalism