View source for Philosophy:Mental substance

{{Descartes}}
'''Mental substance''', according to the idea held by dualists and [[Philosophy:Idealism|idealists]], is a non-physical substance of which minds are composed. This substance is often referred to as [[Philosophy:Consciousness|consciousness]].

This is opposed to the [[Philosophy:Materialism|materialists]], who hold that what we normally think of as mental substance is ultimately physical matter (i.e., brains).

[[Biography:René Descartes|Descartes]], who was most famous for the assertion "I think therefore I am", has had a lot of influence on the [[Philosophy:Mind–body problem|mind–body problem]]. He describes his theory of mental substance (which he calls '''''res cogitans''''' distinguishing it from the ''[[Philosophy:Res extensa|res extensa]]'') in the ''Second Meditation'' (II.8) and in ''Principia Philosophiae'' (2.002).

He used a more precise definition of the word "substance" than is currently popular: that a substance is something which can exist without the existence of any other substance. For many philosophers, this word or the phrase "mental substance" has a special meaning.

Gottfried Leibniz, belonging to the generation immediately after Descartes, held the position that the mental world was built up by [[Philosophy:Monad|monad]]s, mental objects that are not part of the physical world (see ''[[Philosophy:Monadology|Monadology]]'').

According to Descartes, God first created eternal truths and then the world from nothing, governing it with His [[Philosophy:Divine providence|divine providence]]. He took special care of human creatures, placing innate ideas in their thought, starting with the ideas of [[Philosophy:Perfection|perfection]] and [[Infinity|infinity]].<ref>{{cite book|author=Father Battista Mondin, O.P.|title=Ontologia e metafisica|trans-title=Ontology and metaphysics|page=59|language=it|publisher=Edizioni Studio Domenicano|year=2022|edition=3rd|series=Filosofia|issue=47|isbn=978-88-5545-053-9}}</ref>

The distinction between res cogitans and res extensa was taken up in Spinoza's ''Ethics, according to which Thought and [[Philosophy:Res extensa|Extension]] are two infinite attributes of the one divine Substance. Soul and body are in turn two finite modes of Thought and Extension.

==See also==
*Dualism (philosophy of mind)
*''[[Philosophy:Monadology|Monadology]]''
*[[Philosophy:Monism|Monism]]
*Pluralism (philosophy of mind)
*[[Biography:Johannes Jacobus Poortman|Johannes Jacobus Poortman]]

==References==
{{reflist}}

{{DEFAULTSORT:Mental Substance}}
[[Category:Concepts in metaphysics]]
[[Category:Consciousness]]
[[Category:Dualism (philosophy of mind)]]
[[Category:Mental content]]

{{Sourceattribution|Mental substance}}