Res extensa

Res extensa (or corporeal substance) is one of the theree substances that René Descartes

used res extensa to descibe one of the three substances in the Cartesian ontology, alonside and its res cogitans and God.  Translated from Latin, "res extensa" means "extended thing."  In Descartes' substances-attribute-mode ontology, extension is the primary attribute of corporeal substance. 

For example, Descartes describes a piece of Wax in the Second meditation. A solid piece of wax has certain sensorial qualities. However, when the wax is melted, it loses every single apparent quality it had in its solid form. Still, Descartes recognizes in the melted substance the idea of wax.

See also

• Descartes
• Philosophical Dualism

References

• http://radicalacademy.com/phildescartes2.htm

http://www.swif.uniba.it/lei/foldop/foldoc.cgi?res+cogitans+-+res+extensa