''Res extensa'' is one of the two
substances described by
René Descartes
René Descartes ( , ; ; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and Modern science, science. Mathematics was paramou ...
in his
Cartesian ontology (often referred to as "radical
dualism"), alongside ''
res cogitans''. Translated from
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
, "''res extensa''" means "extended thing" while the latter is described as "a thinking and unextended thing".
Descartes often translated ''res extensa'' as "corporeal substance" but it is something that only God can create.
''Res extensa'' vs. ''res cogitans''
''Res extensa'' and ''res cogitans'' are mutually exclusive and this makes it possible to conceptualize the complete intellectual independence from the body.
''Res cogitans'' is also referred to as the soul and is related by thinkers such as
Aristotle
Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...
in his ''De Anima'' to the indefinite realm of potentiality.
On the other hand, ''res extensa'', are entities described by the principles of logic and are considered in terms of definiteness. Due to the polarity of these two concepts, the natural science focused on ''res extensa''.
In the Cartesian view, the distinction between these two concepts is a methodological necessity driven by a distrust of the senses and the ''res extensa'' as it represents the entire material world.
The categorical separation of these two, however, caused a problem, which can be demonstrated in this question: How can a wish (a mental event), cause an arm movement (a physical event)?
Descartes has not provided any answer to this but
Gottfried Leibniz
Gottfried Wilhelm Leibniz (or Leibnitz; – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat who is credited, alongside Isaac Newton, Sir Isaac Newton, with the creation of calculus in ad ...
proposed that it can be addressed by endowing each geometrical point in the ''res extensa'' with mind.
Each of these points is within ''res extensa'' but they are also dimensionless, making them unextended.
In Descartes' substance–attribute–mode ontology, extension is the primary attribute of corporeal substance. He describes a piece of wax in the Second
Meditation (see
Wax argument). A solid piece of wax has certain sensory 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
*
Mind-body dualism
References
{{reflist
Concepts in metaphysics
René Descartes