The Mind-Body Duality

1. The Mind-Body Duality Source: Robert H. Wozniak http://serendip.brynmawr.edu/Mind/Descartes.html

2. Rene Descartes (1596-1650)

3. Mind-Body Dualism • Descartes -- The rational mind connects with the animal body at the pineal gland. Thus, mind affects body and body affects mind. Animals have no minds. • We now know the pineal gland does something else, but… • Is there a “mind” or “soul” independent of the brain?

4. 17th Century Philosophy (1600’s) • Causes and effects must be of similar types: • Physical cause leads to physical effect. • God is the only true cause – Malebranche • Spinoza’s double aspect theory – mind and body are both aspects of God in preestablished coordination. • Leibnitz’s psychophysical parallelism – causation is rejected, coordination remains.

5. 18th Century Philosophy (1700’s) • All is mind vs. all is body. • Berkeley’s “Immaterialism” – There is no body because all matter is perceived by the mind and can’t be known apart from it. • Materialism – there is no mind, only matter. Mental events don’t exist. • La Mettrie, “L’homme machine.” • States of the soul depend upon states of the body.

6. 19th Century Philosophy (1800’s) • Localization of cerebral function showed that the brain is the organ of the mind. • Mental states were shown to affect the body. • Trauma, mesmeric trance, mental suggestion. • Huxley’s “Epiphenomenalism” – • Mental states have no causal efficacy, like paint on a stone (neurophysiology is the stone, mind is the paint). • We are “conscious automata.”

7. Interactionism • Carpenter – mind and brain interact: • Light produces a change in nerves in the brain that results in mental sensation of seeing. • Desire to move is translated into commands to the nerves that move muscles in voluntary motion. • There exist circuits between mental and physical activity. • How this is accomplished is unknown.

8. Dual-Aspect Monism • Lewes – mental and physical processes are two aspects of the same psychophysical event. • Mind is subjective while body is objective. • Terms used to describe the two are not inter-translatable. • Lewes still provides the best argument for why psychology cannot be replaced by neuroscience.

9. Mind-Stuff Theory • Higher properties of mind are compounded from mental elements (pieces of mind-stuff). • When molecules come together at a level of complexity sufficient to form a brain and nervous system, correlative mind-stuff forms consciousness.

10. James’ Idea of Mind-Stuff

11. William James • James adopted a pragmatic empirical parallelism of the sort many psychologists still support. • The "simplest psycho-physic formula…” is a "blank unmediated correspondence, term for term, of the succession of states of consciousness with the succession of total brain processes ..." • Principles of Psychology, p. 182

12. Ongoing Controversy • We still do not know how “mind” emerges from “body.” • The nature of the relationship between specific mental states and the neural substrate is still not understood. • Those debating mind-body today largely express ideas that are versions of the philosophical arguments proposed over the past 250 years.

13. Interview with Rodney Brooks Human as machine, machine as human: http://www.aaai.org/AITopics/html/show.html http://news.bbc.co.uk/olmedia/cta/progs/02/hardtalk/brooks19aug.ram