The foundation of Cartesian dualism is that there are two different types of substances: physical and mental.1 Physical substances have the fundamental property of extension while mental substances have the fundamental property of thought. Furthermore, they are entirely distinct from each other; a physical substance cannot think and a mental substance cannot have extension.2
Another key principle of Cartesian dualism is that humans have a body, in the physical state, and a mind, in the mental state, which interact with each other.3 Descartes compared this union of mind and body to a sailor and his ship in Meditation 6; like how a sailor steers his ship, we too have a thinking thing, existing independently of the body, which controls our body.4 Thus our mind can affect our bodies. Furthermore, Descartes reasoned that our bodies can affect our mind because when our bodies are damaged, our mind perceives this as pain.
However, this raises the issue of mind/body interaction; it seems impossible for a mental substance, with no physical properties, and a material object to affect each other.5
1
Binder, MD, Hirokawa, N & Windhorst, U 2009, Encyclopedia of Neuroscience, Springer Berlin Heidelberg, Berlin.
2
Lloyd, M 2013, Week 3 Descartes I, PowerPoint slides, University of Queensland, Brisbane.
3
McLeod, S 2007, Mind Body Debate, viewed 13th April 2013, .
4
Temple, C 2002, Meditations on First
Bibliography: Binder, MD, Hirokawa, N & Windhorst, U 2009, Encyclopedia of Neuroscience, Springer Berlin Heidelberg, Berlin. Bloom, P 2007, Lecture 2 Foundations: This is Your Brain, Transcript, Yale University, Connecticut. Calef, S 2005, Dualism and Mind, Internet Encyclopaedia of Philosophy, viewed 12th April 2013, . Koksvik, O 2006, In Defense of Interactionism, Monash University, Melbourne, viewed 11th April 2013, . Lisa Shapiro (ed.) The Correspondence Between Princess Elizabeth of Bohemia and Rene Descartes, (Chicago: Chicago University Press, 2007) 61-67. Lloyd, M 2013, Week 3 Descartes I, PowerPoint slides, University of Queensland, Brisbane. Lloyd, M 2013, Week 4 Descartes II, PowerPoint slides, University of Queensland, Brisbane. McLeod, S 2007, Mind Body Debate, viewed 13th April 2013, . Rene Descartes, The Passions of the Soul, trans. John Conttingham, Robert Stoothoff & Dougald Murdoch (Cambridge: CUP, 1985), 340. Temple, C 2002, Meditations on First Philosophy, Philosophy Index, viewed 14th April 2013, .