Dualism

Psy391D - Class 2

(This page last updated 8 Sept, 2004.)

For the next two classes, we will look closely at the different explanations that have been proposed for the relationship between mind and body. The explanations fall into two different types: dualist and materialist. As you will see, there are many specific varieties of each.

Supplemental Reading  In his book Matter and Consciousness, Paul Churchland examines the conflict between materialism and dualism. He begins by stating the problem, which has come to be known the Mind-Body Problem. What is the relationship between mind and body? He also refers to it as the Ontological Problem. Ontology is the study of the nature of existence, and the main question here is whether the mind exists as something nonphysical, apart from the brain. We begin by considering one form of dualism, called substance dualism. Churchland breaks down this concept further, into Cartesian dualism and popular dualism. After explaining substance dualism, he explores property dualism, which includes interactive property dualism and epiphenomalism. Be sure you understand the differences between these different forms of dualism, and the arguments for and against each. These different varieties of dualism are discussed on pages 7-22. After working through the different varieties of dualism, you may want to read the very short chapter in The Mind's I by Raymond Smullyan. I recommend reading both the chapter and the Reflections by Hofstadter and Dennett after it. Note the point they raise that Smullyan's chapter is an argument against epiphenomenalism rather than interactionist dualism (interactionism). Also note that in the Reflections, Hofstadter and Dennett do not make a distinction between substance dualism and property dualism in the way that Churchland does. Both books are available in the Reserve Room, and the Churchland book is also available on the web.

Reduction

Sometimes scientists will try to reduce one area of science into another. For instance, one might try to reduce a particular part of Chemistry into Phyics by explaining the laws of chemistry as the consequences of the laws of physics that describe the intractions among atoms and subatomic particles. Under reduction, one set of scientific laws are replaced by another set of laws that describe systems at a lower level.

Some philosophers expect that we will eventually be able to reduce Psychology into Biology, Biology into Chemistry, and Chemistry into Physics. Others disagree, arguing that important aspects of each science are irreducible. In other words, they cannot be fully explained by the laws from a lower level.

Here we will include both forms of dualism: substance dualism and property dualism.

• Substance Dualism
  • The mind is made of nonphysical substance.
  • Cartesian Dualism
    • Mental substance does not occupy space.
  • Popular Dualism
    • Mental substance does take up space.
• Property Dualism
  • There is no mental substance, but when physical matter is organized into a brain, it develops emergent properties that cannot be explained by physical science..
    • Psychology is irreducible.
  • Interactionist Property Dualism
    • The emergent properties can affect the physical activities of the brain.
    • another alternative: Elemental-Property Dualism
      • Mental properties are irreducible, but not emergent.
      • analogous to electromagnetic radiation
  • Epiphenomenalism
    • Physical phenomena can cause mental phenomena, but mental phenomena have no effect on the physical world.
    • Your thoughts may not occur in the physical world, but they are caused by the activity in your brain.
    • This view is appealing because it allows for the scientific study of behavior, but still allows us to believe that our minds are nonphysical.
    • But can it explain why we talk about our mental states?
• arguments in favor of dualism
  • religion
  • introspection
    • Mental states seem to be different from physial states
  • irreducibility
    • reason
    • language
    • qualia
    • parapsychology
• arguments against dualism
  • Ockham's Razor
  • explanatory impotence
    • Dualism seems to explain little that can't be explained by materialism.
  • neural dependence of all known mental phenomena
    • applies to substance dualism, but not property dualism
  • evolutionary history

next class: Materialism

Psych 391D: Consciousness Kyle Cave Psychology Dept. U. Mass.