Interactionism (philosophy of mind)

Interactionism or interactionist dualism is the theory in the philosophy of mind which holds that matter and mind are two distinct and independent substances that exert causal effects on one another. An example of your mind influencing your body would be if you are depressed (which is related to your mind), you can observe the effects on your body, such as a slouched posture, a lackluster smile, etc. Another example, this time of your body affecting your mind would be: If you struck your toe very forcefully on a door (which is related to your body), you would experience terrible pain (which is related to your mind). Interactionism is one type of dualism, traditionally a type of substance dualism though more recently also sometimes a form of property dualism. Many philosophers and scientists have responded to this theory with arguments both supporting and opposing its relevance to life and whether the theory corresponds to reality. Mind-body dualism#Arguments for dualism Interactionism was propounded by the French rationalist philosopher René Descartes (1596–1650), and continues to be associated with him. Descartes posited that the body, being physical matter, was characterized by spatial extension but not by thought and feeling, while the mind, being a separate substance, had no spatial extension but could think and feel. Nevertheless, he maintained that the two interacted with one another, suggesting that this interaction occurred in the pineal gland of the brain. In the 20th century, its most significant defenders have been the noted philosopher of science Karl Popper and the neurophysiologist John Carew Eccles. Popper, in fact, divided reality into three "worlds"—the physical, the mental, and objective knowledge (outside the mind)—all of which interact, and Eccles adopted this same "trialist" form of interactionism. Other notable recent philosophers to take an interactionist stance have been Richard Swinburne, John Foster, David Hodgson, and Wilfrid Sellars, in addition to the physicist Henry Stapp.