Res extensa

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Res extensa is one of the three substances described by René Descartes in his Cartesian ontology [1] (often referred to as "radical dualism"), alongside res cogitans and God. Translated from Latin, "res extensa" means "extended and unthinking thing" while the latter is described as "a thinking and unextended thing". [2] Descartes often translated res extensa as "corporeal substance" but it is something that only God can create. [3]

Substance theory, or substance–attribute theory, is an ontological theory about objecthood positing that a substance is distinct from its properties. A thing-in-itself is a property-bearer that must be distinguished from the properties it bears.

René Descartes 17th-century French philosopher, mathematician, and scientist

René Descartes ; 31 March 1596 – 11 February 1650) was a French philosopher, mathematician, and scientist. A native of the Kingdom of France, he spent about 20 years (1629–1649) of his life in the Dutch Republic after serving for a while in the Dutch States Army of Maurice of Nassau, Prince of Orange and the Stadtholder of the United Provinces. One of the most notable intellectual figures of the Dutch Golden Age, Descartes is also widely regarded as one of the founders of modern philosophy.

Mental substance idea held by dualists and idealists, that minds are made-up of non-physical substance

Mental substance is the idea held by dualists and idealists, that minds are made-up of non-physical substance. This substance is often referred to as consciousness.


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. [2] Res cogitans is also referred to as the soul and is related by thinkers such as Aristotle in his De Anima to the indefinite realm of potentiality. [4] 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. [4]

Aristotle philosopher in ancient Greece

Aristotle was a Greek philosopher during the Classical period in Ancient Greece, the founder of the Lyceum and the Peripatetic school of philosophy and Aristotelian tradition. Along with his teacher Plato, he has been called the "Father of Western Philosophy". His writings cover many subjects – including physics, biology, zoology, metaphysics, logic, ethics, aesthetics, poetry, theatre, music, rhetoric, psychology, linguistics, economics, politics and government. Aristotle provided a complex synthesis of the various philosophies existing prior to him, and it was above all from his teachings that the West inherited its intellectual lexicon, as well as problems and methods of inquiry. As a result, his philosophy has exerted a unique influence on almost every form of knowledge in the West and it continues to be a subject of contemporary philosophical discussion.

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. [5] 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)? [6] Descartes has not provided any answer to this but Gottfried Leibniz proposed that it can be addressed by endowing each geometrical point in the res extensa with mind. [6] Each of these points is within res extensa but they are also dimensionless, making them unextended. [6]

Gottfried Wilhelm Leibniz German mathematician and philosopher

Gottfried Wilhelm (von) Leibniz was a prominent German polymath and one of the most important logicians, mathematicians and natural philosophers of the Enlightenment. As a representative of the seventeenth-century tradition of rationalism, Leibniz's most notable accomplishment was conceiving the ideas of differential and integral calculus, independently of Isaac Newton's contemporaneous developments. Mathematical works have consistently favored Leibniz's notation as the conventional expression of calculus. It was only in the 20th century that Leibniz's law of continuity and transcendental law of homogeneity found mathematical implementation. He became one of the most prolific inventors in the field of mechanical calculators. While working on adding automatic multiplication and division to Pascal's calculator, he was the first to describe a pinwheel calculator in 1685 and invented the Leibniz wheel, used in the arithmometer, the first mass-produced mechanical calculator. He also refined the binary number system, which is the foundation of all digital computers.

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.

<i>Meditations on First Philosophy</i> philosophy book by Descartes

Meditations on First Philosophy in which the existence of God and the immortality of the soul are demonstrated is a philosophical treatise by René Descartes first published in Latin in 1641. The French translation was published in 1647 as Méditations Métaphysiques. The title may contain a misreading by the printer, mistaking animae immortalitas for animae immaterialitas, as suspected by A. Baillet.

Wax argument

The wax argument or the ball of wax example is a thought experiment that René Descartes created within his Meditations on First Philosophy. He devised it to analyze what properties are essential for bodies, show how uncertain our knowledge of the world is compared to our knowledge of our minds, and argue for rationalism.

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<i>Cogito, ergo sum</i> philosophical proposition by René Descartes

Cogito, ergo sum is a Latin philosophical proposition by René Descartes usually translated into English as "I think, therefore I am". The phrase originally appeared in French as je pense, donc je suis in his Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It appeared in Latin in his later Principles of Philosophy. As Descartes explained, "we cannot doubt of our existence while we doubt...." A fuller version, articulated by Antoine Léonard Thomas, aptly captures Descartes's intent: dubito, ergo cogito, ergo sum. The concept is also sometimes known as the cogito.

Ontology study of the nature of being, becoming, existence or reality, as well as the basic categories of being and their relations

Ontology is the philosophical study of being. More broadly, it studies concepts that directly relate to being, in particular becoming, existence, reality, as well as the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology often deals with questions concerning what entities exist or may be said to exist and how such entities may be grouped, related within a hierarchy, and subdivided according to similarities and differences.

In metaphysics, extension signifies both 'stretching out' as well as later 'taking up space', and most recently, spreading one's internal mental cognition into the external world.

Mind–body dualism Philosophical theory that mental phenomena are non-physical and that matter exists independently of mind

Mind–body dualism, or mind–body duality, is a view in the philosophy of mind that mental phenomena are, in some respects, non-physical, or that the mind and body are distinct and separable. Thus, it encompasses a set of views about the relationship between mind and matter, and between subject and object, and is contrasted with other positions, such as physicalism and enactivism, in the mind–body problem.

Occasionalism is a philosophical theory about causation which says that created substances cannot be efficient causes of events. Instead, all events are taken to be caused directly by God. The theory states that the illusion of efficient causation between mundane events arises out of God's causing of one event after another. However, there is no necessary connection between the two: it is not that the first event causes God to cause the second event: rather, God first causes one and then causes the other.

In philosophy, the Cartesian Self, part of a thought experiment, is an individual's mind, separate from the body and the outside world, thinking about itself and its existence. It is distinguished from the Cartesian Other, anything other than the Cartesian self. According to the philosopher Rene Descartes, there is a divide intrinsic to consciousness, such that one cannot ever bridge the space between one's own consciousness and that of another.

Cartesian circle potential mistake in reasoning attributed to René Descartes

The Cartesian circle is a potential mistake in reasoning attributed to René Descartes.

Trialism in philosophy was introduced by John Cottingham as an alternative interpretation of the mind–body dualism of Rene Descartes. Trialism keeps the two substances of mind and body, but introduces a third attribute, sensation, belonging to the union of mind and body. This allows animals, which do not have thought, to be regarded as having sensation and not as being mere automata.

In ontology and the philosophy of mind, a non-physical entity is a spirit or being that exists outside physical reality. Their existence divides the philosophical school of physicalism from the schools of idealism and dualism; with the latter schools holding that they can exist and the former holding that they cannot. If one posits that non-physical entities can exist, there exist further debates as to their inherent natures and their position relative to physical entities.

<i>Passions of the Soul</i> book

In his final philosophical treatise, The Passions of the Soul, completed in 1649 and dedicated to Queen Christina of Sweden, René Descartes contributes to a long tradition of philosophical enquiry into the nature of "the passions". The passions were experiences – now commonly called emotions in the modern period – that had been a subject of debate among philosophers and theologians since the time of Plato.

Mind–body problem open question in philosophy of how abstract minds interact with physical bodies

The mind–body problem is an unsolved problem concerning the relationship between thought and consciousness in the human mind, and the brain as part of the physical body. It is distinct from the question of how mind and body function chemically and physiologically since that question presupposes an interactionist account of mind-body relations. This question arises when mind and body are considered as distinct, based on the premise that the mind and the body are fundamentally different in nature.

Cartesianism philosophical and scientific system of René Descartes

The Cartesian Method is the philosophical and scientific system of René Descartes and its subsequent development by other seventeenth century thinkers, most notably François Poullain de la Barre, Nicolas Malebranche and Baruch Spinoza. Descartes is often regarded as the first thinker to emphasize the use of reason to develop the natural sciences. For him, the philosophy was a thinking system that embodied all knowledge, and expressed it in this way:

Matter substance that has rest mass and volume, or several other definitions

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light or sound. Matter exists in various states. These include classical everyday phases such as solid, liquid, and gas – for example water exists as ice, liquid water, and gaseous steam – but other states are possible, including plasma, Bose–Einstein condensates, fermionic condensates, and quark–gluon plasma.

Interactionism or interactionist dualism is the theory in the philosophy of mind which holds that matter and mind are two distinct and independent substances that exert causal effects on one another. It is one type of dualism, traditionally a type of substance dualism though more recently also sometimes a form of property dualism.

Mathematicism is any opinion, viewpoint, school of thought, or philosophy that states that everything can be described/defined/modelled ultimately by mathematics, or that the universe and reality are fundamentally/fully/only mathematical, i.e. that 'everything is mathematics' necessitating the ideas of logic, reason, mind, and spirit.


  1. Principia Philosophiae , 2.001.
  2. 1 2 Bordo, Susan (2010). Feminist Interpretations of Rene Descartes. University Park, Pennsylvania: The Pennsylvania State University Press. p. 59. ISBN   0271018577.
  3. Schmaltz, Tad (2008). Descartes on Causation. New York: Oxford University Press. p. 46. ISBN   9780195327946.
  4. 1 2 Aerts, Diederik; Chiara, Maria Luisa Dalla; Ronde, Christian de; Krause, Décio (2018). Probing the Meaning of Quantum Mechanics: Information, Contextuality, Relationalism and EntanglementProceedings of the II International Workshop on Quantum Mechanics and Quantum Information. Physical, Philosophical and Logical Approaches. New Jersey: World Scientific Publishing. p. 134. ISBN   9789813276888.
  5. Cavell, Richard (2003). McLuhan in Space: A Cultural Geography. Toronto: University of Toronto Press. p. 83. ISBN   0802036104.
  6. 1 2 3 Callicott, J. Baird (2013). Thinking Like a Planet: The Land Ethic and the Earth Ethic. New York: Oxford University Press. p. 189. ISBN   9780199324897.