Mental substance, according to the idea held by dualists and

idealists Idealism in philosophy, also known as philosophical realism or metaphysical idealism, is the set of metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, spirit, or consciousness; that reality is enti ...

, is a non-physical substance of which minds are composed. This substance is often referred to as

consciousness Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, an ...

. This is opposed to the view of

materialists Materialism is a form of philosophical monism according to which matter is the fundamental substance in nature, and all things, including mental states and consciousness, are results of material interactions. According to philosophical materia ...

, who hold that what we normally think of as mental substance is ultimately physical matter (i.e., brains).

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 ...

, who was most famous for the assertion " I think therefore I am", played a major role in developing the

mind–body problem The mind–body problem is a List_of_philosophical_problems#Mind–body_problem, philosophical problem concerning the relationship between thought and consciousness in the human mind and Human body, body. It addresses the nature of consciousness ...

. He describes his theory of mental substance (which he calls ''res cogitans'' distinguishing it from the ''

res extensa ''Res extensa'' is one of the two substances described by René Descartes in his Cartesian ontology (often referred to as "radical dualism"), alongside '' res cogitans''. Translated from Latin, "''res extensa''" means "extended thing" while th ...

'') in the ''Second

Meditation Meditation is a practice in which an individual uses a technique to train attention and awareness and detach from reflexive, "discursive thinking", achieving a mentally clear and emotionally calm and stable state, while not judging the meditat ...

'' (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.

History

According to Descartes, God first created eternal truths and then the world from nothing, governing it with His

divine providence In theology, divine providence, or simply providence, is God's intervention in the universe. The term ''Divine Providence'' (usually capitalized) is also used as a names of God, title of God. A distinction is usually made between "general prov ...

. He took special care of human creatures, placing innate ideas in their thought, starting with the ideas of

perfection Perfection is a state, variously, of completeness, flawlessness, or supreme excellence. The terminology, term is used to designate a range of diverse, if often kindred, concepts. These have historically been addressed in a number of discre ...

and

infinity Infinity is something which is boundless, endless, or larger than any natural number. It is denoted by \infty, called the infinity symbol. From the time of the Ancient Greek mathematics, ancient Greeks, the Infinity (philosophy), philosophic ...

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 ...

, belonging to the generation immediately after Descartes, held the position that the mental world was built up of monads, mental objects that are not part of the physical world (see '' Monadology''). The distinction between ''res cogitans'' and ''res extensa'' was taken up in

Spinoza Baruch (de) Spinoza (24 November 163221 February 1677), also known under his Latinized pen name Benedictus de Spinoza, was a philosopher of Portuguese-Jewish origin, who was born in the Dutch Republic. A forerunner of the Age of Enlightenmen ...

's ''

Ethics Ethics is the philosophy, philosophical study of Morality, moral phenomena. Also called moral philosophy, it investigates Normativity, normative questions about what people ought to do or which behavior is morally right. Its main branches inclu ...

'', written between 1661 and 1675, according to which Thought and Extension are two infinite attributes of the one divine Substance. Soul and body are in turn two finite modes of Thought and Extension.

References

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

History

See also

References