Dualism (philosophy of mind) - AbsoluteAstronomy.com

Philosophy of mind

Philosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...

, dualism is a set of views about the relationship between mind and matter, which begins with the claim that mental

Mind

The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...

phenomena are, in some respects, non-physical

Non-physical entity

A non-physical entity is an entity that lacks a physical or material body or material or physical characteristics. Non-physical entities may be considered hypothetical, e.g...

.

While Aristotle

Aristotle

Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

shared Plato

Plato

Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...

's view of multiple souls, (ψυχή psychí) their hierarchical arrangement corresponded to distinctive functions of plants, animals and people: a nutritive soul of growth and metabolism, shared by all three, a perceptive soul of pain, pleasure and desire, shared by animals and people only, and the faculty of reason, unique to humanity. In his view, a soul is the hylomorphic form a viable organism, where each level of the hierarchy formally supervenes upon the substance

Substance theory

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....

of the preceding level. Thus, for Aristotle, all three souls perish when the living organism dies. For Plato however, the soul migrates

Metempsychosis

Metempsychosis is a philosophical term in the Greek language referring to transmigration of the soul, especially its reincarnation after death. It is a doctrine popular among a number of Eastern religions such as Hinduism, Buddhism, Jainism and Druzism wherein an individual incarnates from one...

to a new body after death and is not identified with the physical body.

Dualism is closely associated with the philosophy of René Descartes

René Descartes

René Descartes ; was a French philosopher and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day...

(1641), which holds that the mind is a nonphysical substance. Descartes was the first to clearly identify the mind with consciousness

Consciousness

Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

and self-awareness and to distinguish this from the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

, which was the seat of intelligence

Intelligence

Intelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....

. Hence, he was the first to formulate the mind-body problem in the form in which it exists today. Dualism is contrasted with various kinds of monism

Monism

Monism is any philosophical view which holds that there is unity in a given field of inquiry. Accordingly, some philosophers may hold that the universe is one rather than dualistic or pluralistic...

, including phenomenalism

Phenomenalism

Phenomenalism is the view that physical objects do not exist as things in themselves but only as perceptual phenomena or sensory stimuli situated in time and in space...

. Substance dualism is contrasted with all forms of materialism

Materialism

In philosophy, the theory of materialism holds that the only thing that exists is matter; that all things are composed of material and all phenomena are the result of material interactions. In other words, matter is the only substance...

, but property dualism

Property dualism

Property dualism describes a category of positions in the philosophy of mind which hold that, although the world is constituted of just one kind of substance - the physical kind - there exist two distinct kinds of properties: physical properties and mental properties...

may be considered a form of emergent materialism

Emergent materialism

In the philosophy of mind, emergent materialism is a theory which asserts that the mind is an irreducible existent in some sense, albeit not in the sense of being an ontological simple, and that the study of mental phenomena is independent of other sciences.The view can be divided into emergence...

and thus would only be contrasted with non-emergent materialism

Emergent materialism

. This article discusses the various forms of dualism and the argument

Argument

In philosophy and logic, an argument is an attempt to persuade someone of something, or give evidence or reasons for accepting a particular conclusion.Argument may also refer to:-Mathematics and computer science:...

s which have been made both for and against this thesis.

Plato and Aristotle

In the dialogue Phaedo

Phaedo

Plato's Phaedo is one of the great dialogues of his middle period, along with the Republic and the Symposium. The Phaedo, which depicts the death of Socrates, is also Plato's seventh and last dialogue to detail the philosopher's final days .In the dialogue, Socrates...

, Plato

Plato

formulated his famous Theory of Forms

Theory of Forms

Plato's theory of Forms or theory of Ideas asserts that non-material abstract forms , and not the material world of change known to us through sensation, possess the highest and most fundamental kind of reality. When used in this sense, the word form is often capitalized...

as distinct and immaterial substances of which the objects and other phenomena that we perceive in the world are nothing more than mere shadows.

Plato makes it clear, in the Phaedo, that the Forms are the universalia ante res, i.e. they are ideal universals, by which we are able to understand the world. In his allegory of the cave

Allegory of the cave

The Allegory of the Cave—also known as the Analogy of the Cave, Plato's Cave, or the Parable of the Cave—is an allegory used by the Greek philosopher Plato in his work The Republic to illustrate "our nature in its education and want of education"...

Plato likens the achievement of philosophical understanding to emerging into the sun from a dark cave, where only vague shadows of what lies beyond that prison are cast dimly upon the wall. Plato's forms are non-physical and non-mental. They exist nowhere in time or space, but neither do they exist in the mind, nor in the pleroma

Pleroma

Pleroma generally refers to the totality of divine powers. The word means fullness from comparable to πλήρης which means "full", and is used in Christian theological contexts: both in Gnosticism generally, and by Paul of Tarsus in Colossians Colossians 2:9 KJV .Gnosticism holds that the...

of matter; rather, matter is said to “participate” in form (μεθεξις methexis). It remained unclear however, even to Aristotle, exactly what Plato intended by that.

Aristotle

Aristotle

argued at length against many aspects of Plato's forms, creating his own doctrine of hylomorphism wherein form and matter coexist. Ultimately however, Aristotle's aim was to perfect a theory of forms, rather than to reject it. Although Aristotle strongly rejected the independent existence Plato attributed to forms, his metaphysics do agree with Plato's a priori considerations quite often however. For example, Aristotle's argument that changeless, eternal substantial form is necessarily immaterial. Because matter provides a stable substratum for a change in form, matter always has the potential to change. Thus, if given an eternity in which to do so, it will, necessarily, exercise that potential.

Part of Aristotle's psychology, the study of the soul, is his account of the ability of humans to reason and the ability of animals to perceive. In both cases, perfect copies of forms are acquired, either by direct impression of environmental forms, in the case of perception, or else by virtue of contemplation, understanding and recollection. He believed the mind can literally assume any form being contemplated or experienced, and it was unique in its ability to become a blank slate, having no essential form. As thoughts of earth are not heavy, any more than thoughts of fire are casually efficient, they provide an immaterial complement for the formless mind.

From Neoplatonism to Scholasticism

In the early Middle Ages, there was a resurgence of what is now called Neoplatonism

Neoplatonism

Neoplatonism , is the modern term for a school of religious and mystical philosophy that took shape in the 3rd century AD, based on the teachings of Plato and earlier Platonists, with its earliest contributor believed to be Plotinus, and his teacher Ammonius Saccas...

, which is generally based on Plato's philosophy. Neoplatonism exerted a considerable influence on Christianity

Christianity

Christianity is a monotheistic religion based on the life and teachings of Jesus as presented in canonical gospels and other New Testament writings...

, as did the philosophy of Aristotle via scholasticism

Scholasticism

Scholasticism is a method of critical thought which dominated teaching by the academics of medieval universities in Europe from about 1100–1500, and a program of employing that method in articulating and defending orthodoxy in an increasingly pluralistic context...

.

In the scholastic tradition of Saint Thomas Aquinas, officially incorporated into Roman Catholic dogma

Dogma

Dogma is the established belief or doctrine held by a religion, or a particular group or organization. It is authoritative and not to be disputed, doubted, or diverged from, by the practitioners or believers...

, the soul remains the substance of a human being, as it did per Aristotle. Aquinas, however, provided for the separation of the soul from the body, although the soul by itself, was understood not to be a person (substance). Hence, Aquinas suggested that "soul of St. Peter pray for us" would be more appropriate than "St. Peter pray for us", because all things connected with his person, including memories, ended with his corporeal life.

The Catholic

Catholic

The word catholic comes from the Greek phrase , meaning "on the whole," "according to the whole" or "in general", and is a combination of the Greek words meaning "about" and meaning "whole"...

doctrine of the resurrection of the body states that at the second coming

Second Coming

In Christian doctrine, the Second Coming of Christ, the Second Advent, or the Parousia, is the anticipated return of Jesus Christ from Heaven, where he sits at the Right Hand of God, to Earth. This prophecy is found in the canonical gospels and in most Christian and Islamic eschatologies...

, the souls of the departed will be reunited with their bodies as a whole person (substance) and witness to the apocalypse

Apocalypse

An Apocalypse is a disclosure of something hidden from the majority of mankind in an era dominated by falsehood and misconception, i.e. the veil to be lifted. The Apocalypse of John is the Book of Revelation, the last book of the New Testament...

. The thorough consistency between dogma and Aristotelian physics

Aristotelian physics

Aristotelian Physics the natural sciences, are described in the works of the Greek philosopher Aristotle . In the Physics, Aristotle established general principles of change that govern all natural bodies; both living and inanimate, celestial and terrestrial—including all motion, change in respect...

evident here resulted from a belief that there can be only one truth. Consistency with science and logic remained a high priority for centuries, and a university doctorate in theology generally included the entire science curriculum as a prerequisite. This doctrine is not universally accepted by Christians today. Many believe that one's immortal soul goes directly to Heaven

Heaven

Heaven, the Heavens or Seven Heavens, is a common religious cosmological or metaphysical term for the physical or transcendent place from which heavenly beings originate, are enthroned or inhabit...

upon death of the body.

Descartes and his disciples

In his Meditations on First Philosophy

Meditations on First Philosophy

Meditations on First Philosophy is a philosophical treatise written by René Descartes and first published in 1641 . The French translation was published in 1647 as Méditations Metaphysiques...

, Descartes

René Descartes

embarked upon a quest in which he called all his previous beliefs into doubt, in order to find out of what he could be certain. In so doing, he discovered that he could doubt whether he had a body (it could be that he was dreaming of it or that it was an illusion created by an evil demon), but he could not doubt whether he had a mind. This gave Descartes his first inkling that the mind and body were different things. The mind, according to Descartes, was a "thinking thing" (lat. res cogitans), and an immaterial substance

Substance theory

. This "thing" was the essence of himself, that which doubts, believes, hopes, and thinks. The distinction between mind and body is argued in Meditation VI as follows: I have a clear and distinct idea of myself as a thinking, non-extended thing, and a clear and distinct idea of body as an extended and non-thinking thing. Whatever I can conceive clearly and distinctly, God can so create. So, Descartes argues, the mind, a thinking thing, can exist apart from its extended body. And therefore, the mind is a substance distinct from the body, a substance whose essence is thought.

The central claim of what is often called Cartesian dualism, in honour of Descartes, is that the immaterial mind and the material body, while being ontologically

Ontology

Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...

distinct substances, causally interact. This is an idea which continues to feature prominently in many non-European philosophies. Mental events cause physical events, and vice-versa. But this leads to a substantial problem for Cartesian dualism: How can an immaterial mind cause anything in a material body, and vice-versa? This has often been called the "problem of interactionism."

Descartes himself struggled to come up with a feasible answer to this problem. In his letter to Elisabeth of Bohemia, Princess Palatine

Elisabeth of Bohemia, Princess Palatine

Elisabeth of the Palatinate , also known as Elisabeth of Bohemia, was the eldest daughter of Frederick V, who was briefly elected King of Bohemia, and Elizabeth Stuart. She ruled the Herford Abbey as Princess-Abbess Elizabeth III...

, he suggested that animal spirits interacted with the body through the pineal gland

Pineal gland

The pineal gland is a small endocrine gland in the vertebrate brain. It produces the serotonin derivative melatonin, a hormone that affects the modulation of wake/sleep patterns and seasonal functions...

, a small gland in the centre of the brain

Brain

, between the two hemispheres. The term "Cartesian dualism" is also often associated with this more specific notion of causal interaction through the pineal gland. However, this explanation was not satisfactory: how can an immaterial mind interact with the physical pineal gland? Because Descartes' was such a difficult theory to defend, some of his disciples, such as Arnold Geulincx

Arnold Geulincx

Arnold Geulincx was a Flemish philosopher. He was one of the followers of René Descartes who tried to work out more detailed versions of a generally Cartesian philosophy...

and Nicholas Malebranche, proposed a different explanation: That all mind-body interactions required the direct intervention of God

God

God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....

. According to these philosophers, the appropriate states of mind and body were only the occasions for such intervention, not real causes. These occasionalists

Occasionalism

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...

maintained the strong thesis that all causation was directly dependent on God, instead of holding that all causation was natural except for that between mind and body.

Types of mind-body dualism

Ontological dualism makes dual commitments about the nature of existence as it relates to mind and matter, and can be divided into three different types:

Substance dualism asserts that mind and matter are fundamentally distinct kinds of substances.
Property dualism suggests that the ontological distinction lies in the differences between properties of mind and matter (as in emergentism
Emergentism
In philosophy, emergentism is the belief in emergence, particularly as it involves consciousness and the philosophy of mind, and as it contrasts with reductionism. A property of a system is said to be emergent if it is in some sense more than the "sum" of the properties of the system's parts...

).
Predicate dualism claims the irreducibility of mental predicates to physical predicates.

Substance dualism

Substance dualism is a type of dualism most famously defended by Descartes, which states that there are two fundamental kinds of substance: mental and material. According to his philosophy, which is specifically called Cartesian dualism, the mental does not have extension in space, and the material cannot think. Substance dualism is important historically for having given rise to much thought regarding the famous mind-body problem. Substance dualism is a philosophical position compatible with most theologies

Theology

Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...

which claim that immortal souls occupy an independent "realm" of existence distinct from that of the physical world.
David Chalmers

David Chalmers

David John Chalmers is an Australian philosopher specializing in the area of philosophy of mind and philosophy of language, whose recent work concerns verbal disputes. He is Professor of Philosophy and Director of the Centre for Consciousness at the Australian National University...

recently developed a thought experiment

Thought experiment

A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

inspired by the movie The Matrix

The Matrix

The Matrix is a 1999 science fiction-action film written and directed by Larry and Andy Wachowski, starring Keanu Reeves, Laurence Fishburne, Carrie-Anne Moss, Joe Pantoliano, and Hugo Weaving...

in which substance dualism could be true: Consider a computer simulation in which the bodies of the creatures are controlled by their minds and the minds remain strictly external to the simulation. The creatures can do all the science they want in the world, but they will never be able to figure out where their minds are, for they do not exist in their observable universe. This is a case of substance dualism with respect to computer simulation. This naturally differs from a computer simulation in which the minds are part of the simulation. In such a case, substance monism

Monism

Monism is any philosophical view which holds that there is unity in a given field of inquiry. Accordingly, some philosophers may hold that the universe is one rather than dualistic or pluralistic...

would be true.

Property dualism

Property dualism asserts that an ontological distinction lies in the differences between properties of mind and matter, and that consciousness is ontologically irreducible to neurobiology and physics. It asserts that when matter is organized in the appropriate way (i.e., in the way that living human bodies are organized), mental properties emerge. Hence, it is a sub-branch of emergent materialism

Emergent materialism

. What views properly fall under the property dualism rubric is itself a matter of dispute. There are different versions of property dualism, some of which claim independent categorisation.

Non-reductive physicalism

Non-reductive physicalism is a form of Property Dualism, in which it is asserted that all mental states are causally reducible to physical states. One argument for this has been made in the form of anomalous monism

Anomalous monism

Anomalous monism is a philosophical thesis about the mind-body relationship. It was first proposed by Donald Davidson in his 1970 paper Mental events. The theory is twofold and states that mental events are identical with physical events, and that the mental is anomalous, i.e. under their mental...

expressed by Donald Davidson

Donald Davidson (philosopher)

Donald Herbert Davidson was an American philosopher born in Springfield, Massachusetts, who served as Slusser Professor of Philosophy at the University of California, Berkeley from 1981 to 2003 after having also held teaching appointments at Stanford University, Rockefeller University, Princeton...

, where it is argued that mental events are identical to physical events, and there can be strict law-governed causal relationships. Another argument for this has been expressed by John Searle

John Searle

John Rogers Searle is an American philosopher and currently the Slusser Professor of Philosophy at the University of California, Berkeley.-Biography:...

, who is the advocate of a distinctive form of physicalism he calls biological naturalism

Biological naturalism

Biological naturalism is a monist theory about the relationship between mind and body , and hence an approach to the mind-body problem...

. His view is that although mental states are ontologically

Ontology

Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...

irreducible to physical states, they are causally reducible (see causality

Causality

Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....

). He has acknowledged that "to many people" his views and those of property dualists look a lot alike. But he thinks the comparison is misleading.

Epiphenomenalism

In philosophy of mind, epiphenomenalism, also known as Type-E Dualism, is a view that "mental" states do not have any influence on "physical" states.-Background:...

is a form of Property Dualism, in which it is asserted that one or more mental states do not have any influence on physical states (both ontologically and causally irreducible). It asserts that while material causes give rise to sensations, volition

Volition

Volition may refer to:*Volition , the cognitive process by which an individual decides on and commits to a particular course of action...

s, idea

Idea

In the most narrow sense, an idea is just whatever is before the mind when one thinks. Very often, ideas are construed as representational images; i.e. images of some object. In other contexts, ideas are taken to be concepts, although abstract concepts do not necessarily appear as images...

s, etc., such mental phenomena themselves cause nothing further: they are causal dead-ends. This can be contrasted to interactionism

Interactionism (philosophy of mind)

Interactionism is the theory in the philosophy of mind which holds that, matter and mind being distinct and independent, that they exert causal effects on one another. As such, it is a type of dualism...

, on the other hand, in which mental causes can produce material effects, and vice-versa.

Predicate dualism

Predicate dualism is the view espoused by most nonreductive physicalists, such as Donald Davidson

Donald Davidson (philosopher)

and Jerry Fodor

Jerry Fodor

Jerry Alan Fodor is an American philosopher and cognitive scientist. He holds the position of State of New Jersey Professor of Philosophy at Rutgers University and is the author of many works in the fields of philosophy of mind and cognitive science, in which he has laid the groundwork for the...

, who maintain that while there is only one ontological category of substances and properties of substances (usually physical), the predicates that we use to describe mental events cannot be redescribed in terms of (or reduced to) physical predicates of natural languages. If we characterize predicate monism as the view subscribed to by eliminative materialists

Eliminative materialism

Eliminative materialism is a materialist position in the philosophy of mind. Its primary claim is that people's common-sense understanding of the mind is false and that certain classes of mental states that most people believe in do not exist...

, who maintain that such intentional predicates as believe, desire, think, feel, etc., will eventually be eliminated from both the language of science and from ordinary language because the entities to which they refer do not exist, then predicate dualism is most easily defined as the negation of this position. Predicate dualists believe that so-called "folk psychology", with all of its propositional attitude

Propositional attitude

A propositional attitude is a relational mental state connecting a person to a proposition. They are often assumed to be the simplest components of thought and can express meanings or content that can be true or false...

ascriptions, is an ineliminable part of the enterprise of describing, explaining and understanding human mental states and behavior.

Davidson, for example, subscribes to Anomalous Monism

Anomalous monism

, according to which there can be no strict psycho-physical laws which connect mental and physical events under their descriptions as mental and physical events. However, all mental events also have physical descriptions. It is in terms of the latter that such events can be connected in law-like relations with other physical events. Mental predicates are irreducibly different in character (rational, holistic and necessary) from physical predicates (contingent, atomic and causal).

Dualist views of mental causation

Interactionism

Interactionism is the view that mental states, such as beliefs and desires, causally interact with physical states. This is a position which is very appealing to common-sense intuitions, notwithstanding the fact that it is very difficult to establish its validity or correctness by way of logic

Logic

In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

al argumentation or empirical proof. It seems to appeal to common-sense because we are surrounded by such everyday occurrences as a child's touching a hot stove (physical event) which causes him to feel pain (mental event) and then yell and scream (physical event) which causes his parents to experience a sensation of fear and protectiveness (mental event) and so on.

Parallelism

Psycho-physical parallelism is a very unusual view about the interaction between mental and physical events which was most prominently, and perhaps only truly, advocated by Gottfried Wilhelm von Leibniz

Gottfried Leibniz

Gottfried Wilhelm Leibniz was a German philosopher and mathematician. He wrote in different languages, primarily in Latin , French and German ....

. Like Malebranche and others before him, Leibniz recognized the weaknesses of Descartes' account of causal interaction taking place in a physical location in the brain. Malebranche decided that such a material basis of interaction between material and immaterial was impossible and therefore formulated his doctrine of occasionalism

Occasionalism

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...

, stating that the interactions were really caused by the intervention of God on each individual occasion. Leibniz's idea is that God has created a pre-established harmony

Pre-established harmony

Gottfried Leibniz's theory of pre-established harmony is a philosophical theory about causation under which every "substance" only affects itself, but all the substances in the world nevertheless seem to causally interact with each other because they have been programmed by God in advance to...

such that it only seems as if physical and mental events cause, and are caused by, one another. In reality, mental causes only have mental effects and physical causes only have physical effects. Hence the term parallelism is used to describe this view.

Occasionalism

Occasionalism is a philosophical doctrine about causation which says that created substances cannot be efficient causes of events. Instead, all events are taken to be caused directly by God himself. The theory states that the illusion of efficient causation between mundane events arises out of a constant conjunction that God had instituted, such that every instance where the cause is present will constitute an "occasion" for the effect to occur as an expression of the aforementioned power. This "occasioning" relation, however, falls short of efficient causation. In this view, it is not the case that the first event causes God to cause the second event: rather, God first caused one and then caused the other, but chose to regulate such behaviour in accordance with general laws of nature. Some of its most prominent historical exponents have been Louis de la Forge

Louis de La Forge

Louis de La Forge was a French philosopher who in his Tractatus de mente humana expounded a doctrine of occasionalism...

, Arnold Geulincx

Arnold Geulincx

Arnold Geulincx was a Flemish philosopher. He was one of the followers of René Descartes who tried to work out more detailed versions of a generally Cartesian philosophy...

, and Nicholas Malebranche.

Epiphenomenalism

According to epiphenomenalism

Epiphenomenalism

In philosophy of mind, epiphenomenalism, also known as Type-E Dualism, is a view that "mental" states do not have any influence on "physical" states.-Background:...

, all mental events are caused by a physical event and have no physical consequences, and that one or more mental states do not have any influence on physical states. So, the mental event of deciding to pick up a rock ("M") is caused by the firing of specific neurons in the brain ("P"). When the arm and hand move to pick up the rock ("E") this is not caused by the preceding mental event M, nor by M and P together, but only by P. The physical causes are in principle reducible to fundamental physics, and therefore mental causes are eliminated using this reductionist explanation. If P causes both M and E, there is no overdetermination

Overdetermination

Overdetermination, the idea that a single observed effect is determined by multiple causes at once , was originally a key concept of Sigmund Freud's psychoanalysis....

in the explanation for E.

The idea that even if the animal were conscious nothing would be added to the production of behavior, even in animals of the human type, was first voiced by La Mettrie

Julien Offray de La Mettrie

Julien Offray de La Mettrie was a French physician and philosopher, and one of the earliest of the French materialists of the Enlightenment...

(1745), and then by Cabanis

Pierre Jean George Cabanis

-Further reading:- Further reading :----...

(1802), and was further explicated by Hodgson

Hodgson

Hodgson is a surname. In Britain, the Hodgson surname was the 173rd most common in 1881 and the 206th most common in 1998. In the United States of America, Hodgson was the 3753rd most popular surname in the 1990 census.-Origin and Meaning:The surname authority P. H...

(1870) and Huxley (1874).

Non-reductive physicalism

Non-reductive physicalism is the idea that while mental states are physical they are not reducible to physical properties, in that an ontological distinction lies in the differences between the properties of mind and matter. According to non-reductive physicalism all mental states are causally reducible to physical states where mental properties map to physical properties and vice-versa. A prominent form of non-reductive physicalism called anomalous monism

Anomalous monism

was first proposed by Donald Davidson

Donald Davidson (philosopher)

in his 1970 paper Mental events, where it is claimed that mental event

Mental event

A mental event is a particular occurrence of something going on in the mind or mind substitute. It can be a thought, a dream, a feeling, a realization, or any other mental activity. Mental events are not limited to human thought but can be associated with animal and artificial intelligence as...

s are identical with physical events, and that the mental is anomalous, i.e. under their mental descriptions these mental events are not regulated by strict physical law

Physical law

A physical law or scientific law is "a theoretical principle deduced from particular facts, applicable to a defined group or class of phenomena, and expressible by the statement that a particular phenomenon always occurs if certain conditions be present." Physical laws are typically conclusions...

Arguments for dualism

Subjective argument in support of dualism

A very important argument against physicalism (and hence in favor of some sort of dualism) consists in the idea that the mental and the physical seem to have quite different and perhaps irreconcilable
properties.

Mental events have a certain subjective quality to them, whereas physical seem not to. So, for example, one may ask what a burned finger feels like, or what the blueness of the sky looks like, or what nice music sounds like.

Philosophers of mind call the subjective aspects of mental events qualia

Qualia

Qualia , singular "quale" , from a Latin word meaning for "what sort" or "what kind," is a term used in philosophy to refer to subjective conscious experiences as 'raw feels'. Examples of qualia are the pain of a headache, the taste of wine, the experience of taking a recreational drug, or the...

(or raw feels). There is something that it's like to feel pain, to see a familiar shade of blue, and so on. There are qualia involved in these mental events. And the claim is that qualia seem particularly difficult to reduce to anything physical.

Thomas Nagel

Thomas Nagel

Thomas Nagel is an American philosopher, currently University Professor of Philosophy and Law at New York University, where he has taught since 1980. His main areas of philosophical interest are philosophy of mind, political philosophy and ethics...

, himself a physicalist, first characterized the problem of qualia for physicalistic monism in his article, "What is it like to be a bat?". Nagel argued that even if we knew everything there was to know from a third-person, scientific perspective about a bat's sonar system, we still wouldn't know what it is like to be a bat.

Frank Jackson

Frank Cameron Jackson

Frank Cameron Jackson is an Australian philosopher, currently Distinguished Professor and former Director of the Research School of Social Sciences at Australian National University. In 2007-2008, he also became a regular visiting professor of philosophy at Princeton University...

formulated his famous knowledge argument based upon similar considerations. In this thought experiment

Thought experiment

A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

, known as Mary's room

Mary's room

Mary's room is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" and extended in "What Mary Didn't Know"...

, he asks us to consider a neuroscientist, Mary, who was born, and has lived all of her life, in a black and white room with a black and white television and computer monitor where she collects all the scientific data she possibly can
on the nature of colours. Jackson asserts that as soon as Mary leaves the room, she will come to have new knowledge which she did not possess before: the knowledge of the experience of colours (i.e., what they are like). Although, by hypothesis, Mary had already known everything there is to know about colours from an objective, third-person perspective, she never knew, according to Jackson, what it was like to see red, orange, or green.

If Mary really learns something new, it must be knowledge of something non-physical, since she already knew everything there is to know about the physical aspects of colour. David Lewis

David Kellogg Lewis

David Kellogg Lewis was an American philosopher. Lewis taught briefly at UCLA and then at Princeton from 1970 until his death. He is also closely associated with Australia, whose philosophical community he visited almost annually for more than thirty years...

' response to this argument, now known as the ability argument, is that what Mary really came to know was simply the ability to recognize and identify color sensations to which she had previously not been exposed. Daniel Dennett

Daniel Dennett

Daniel Clement Dennett is an American philosopher, writer and cognitive scientist whose research centers on the philosophy of mind, philosophy of science and philosophy of biology, particularly as those fields relate to evolutionary biology and cognitive science. He is currently the Co-director of...

and others also provide arguments against this notion, see Mary's room

Mary's room

Mary's room is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" and extended in "What Mary Didn't Know"...

for details.

Special sciences argument

This argument says that, if predicate dualism is correct, then there are special sciences which are irreducible to physics. These irreducible special sciences, which are the source of allegedly irreducible predicates, presumably differ from the hard sciences in that they are interest-relative. If they are interest-relative, then they must be dependent on the existence of minds which are capable of having interested perspectives. Psychology is, of course, the paragon of special sciences; therefore, it and its predicates must depend even more profoundly on the existence of the mental.

Physics, at least ideally, sets out to tell us how the world is in itself, to carve up the world at its joints and describe it to us without the interference of individual perspectives or personal interests. On the other hand, such things as the patterns of the weather seen in meteorology or the behavior of human beings are only of interest to human beings as such. The point is that having a perspective on the world is a psychological state. Therefore, the special sciences presuppose the existence of minds which can have these states. If one is to avoid ontological dualism, then the mind that has a perspective must be part of the physical reality to which it applies its perspective. If this is the case, then in order to perceive the physical world as psychological, the mind must have a perspective on the physical. This, in turn, presupposes the existence of mind.

The zombie argument

The zombie argument is based on a thought experiment

Thought experiment

A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

proposed by David Chalmers

David Chalmers

. The basic idea is that one can imagine, and therefore conceive the existence of, one's body without any conscious states being associated with it.

Chalmers' argument is that it seems very plausible that such a being could exist because all that is needed is that all and only the things that the physical sciences describe about a zombie must be true of it. Since none of the concepts involved in these sciences make reference to consciousness or other mental phenomena, and any physical entity can be by definition described scientifically via physics

Physics

Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

, the move from conceivability to possibility is not such a large one.

Others such as Dennett have argued that the notion of a philosophical zombie is an incoherent, or unlikely, concept. In particular, nothing proves that an entity (e.g. a computer or robot) which would perfectly mimic human beings, and especially perfectly mimic expressions of feelings (like joy, fear, anger, ...), would not indeed experience them, thus having similar states of consciousness to what a real human would have. It is argued that under physicalism

Physicalism

Physicalism is a philosophical position holding that everything which exists is no more extensive than its physical properties; that is, that there are no kinds of things other than physical things...

, one must either believe that anyone including oneself might be a zombie, or that no one can be a zombie - following from the assertion that one's own conviction about being (or not being) a zombie is a product of the physical world and is therefore no different from anyone else's.

Argument from personal identity

This argument concerns the differences between the applicability of counterfactual conditionals to physical objects, on the one hand, and to conscious, personal agents on the other. In the case of any material object, e.g. a printer, we can formulate a series of counterfactuals in the following manner:

This printer could have been made of straw.
This printer could have been made of some other kind of plastics and vacuum-tube transistors.
This printer could have been made of 95% of what it is actually made of and 5% vacuum-tube transistors, etc..

Somewhere along the way from the printer's being made up exactly of the parts and materials which actually constitute it to the printer's being made up of some different matter at, say, 20%, the question of whether this printer is the same printer becomes a matter of arbitrary convention.

Imagine the case of a person, Frederick, who has a counterpart born from the same egg and a slightly genetically modified sperm

Genetically modified sperm

Genetically modified sperm is sperm that has undergone genetic modification for biomedical purposes, such as the elimination of genetic diseases or infertility for example....

. Imagine a series of counterfactual cases corresponding to the examples applied to the printer. Somewhere along the way, one is no longer sure about the identity of Frederick. In this latter case, it has been claimed, overlap of constitution cannot be applied to the identity of mind. As Madell puts it:

"But while my present body can thus have its partial counterpart in some possible world, my present consciousness cannot. Any present state of consciousness that I can imagine either is or is not mine. There is no question of degree here."

If the counterpart of Frederick, Frederickus, is 70% constituted of the same physical substance as Frederick, does this mean that it is also 70% mentally identical with Frederick? Does it make sense to say that something is mentally 70% Frederick? A possible solution to this dilemma is that of open individualism

Open individualism

Open individualism is the view in philosophy according to which there exists only one numerically identical subject who is everyone. It is a theoretical solution for the question of personal identity....

Argument from reason

Philosophers and scientists such as Victor Reppert, William Hasker

William Hasker

R. William Hasker is an American Christian philosopher and Distinguished Professor Emeritus of philosophy at Huntington University. For many years he was editor of the prestigious journal Faith and Philosophy. He has published many journal articles and books dealing with issues such as the...

and Alvin Plantinga

Alvin Plantinga

Alvin Carl Plantinga is an American analytic philosopher and the emeritus John A. O'Brien Professor of Philosophy at the University of Notre Dame. He is known for his work in philosophy of religion, epistemology, metaphysics, and Christian apologetics...

have developed an argument for dualism dubbed the "Argument from Reason" and credit C.S. Lewis—who called it "The Cardinal Difficulty of Naturalism," the title of chapter three of the book—with first bringing the argument to light in his book Miracles.

In short the argument holds that if, as thoroughgoing naturalism entails, all of our thoughts are the effect of a physical cause, then we have no reason for assuming that they are also the consequent of a reasonable ground. Knowledge, however, is apprehended by reasoning from ground to consequent. Therefore, if naturalism were true, there would be no way of knowing it—or anything else not the direct result of a physical cause—and we could not even suppose it, except by a fluke.

By this logic, the statement "I have reason to believe naturalism is valid" is self-referentially incoherent in the same manner as the sentence "One of the words of this sentence does not have the meaning that it appears to have," or the statement "I never tell the truth." That is, in each case to assume the veracity of the conclusion would eliminate the possibility of valid grounds from which to reach it. To summarize the argument in the book, Lewis quotes J. B. S. Haldane

J. B. S. Haldane

John Burdon Sanderson Haldane FRS , known as Jack , was a British-born geneticist and evolutionary biologist. A staunch Marxist, he was critical of Britain's role in the Suez Crisis, and chose to leave Oxford and moved to India and became an Indian citizen...

who appeals to a similar line of reasoning:

If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason to suppose that my beliefs are true ... and hence I have no reason for supposing my brain to be composed of atoms.

—J. B. S. Haldane
J. B. S. Haldane
John Burdon Sanderson Haldane FRS , known as Jack , was a British-born geneticist and evolutionary biologist. A staunch Marxist, he was critical of Britain's role in the Suez Crisis, and chose to leave Oxford and moved to India and became an Indian citizen...

, Possible Worlds, page 209

In his essay Is Theology Poetry, Lewis himself summarises the argument in a similar fashion when he writes:

If minds are wholly dependent on brains, and brains on biochemistry, and biochemistry (in the long run) on the meaningless flux of the atoms, I cannot understand how the thought of those minds should have any more significance than the sound of the wind in the trees.

—C. S. Lewis
C. S. Lewis
Clive Staples Lewis , commonly referred to as C. S. Lewis and known to his friends and family as "Jack", was a novelist, academic, medievalist, literary critic, essayist, lay theologian and Christian apologist from Belfast, Ireland...

, The Weight of Glory, page 139

Causal Interaction

If consciousness (the mind) can exist independently of physical reality (the brain), one must explain how physical memories are created concerning consciousness. Dualism must therefore explain how consciousness affects physical reality.

One possible explanation is that of a miracle, proposed by Arnold Geulincx

Arnold Geulincx

Arnold Geulincx was a Flemish philosopher. He was one of the followers of René Descartes who tried to work out more detailed versions of a generally Cartesian philosophy...

and Nicholas Malebranche, where all mind-body interactions require the direct intervention of God.

Although at the time C. S. Lewis wrote Miracles, Quantum Mechanics

Quantum mechanics

Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...

(and physical indeterminism

Indeterminism

Indeterminism is the concept that events are not caused, or not caused deterministically by prior events. It is the opposite of determinism and related to chance...

) was only in the initial stages of acceptance, he stated the logical possibility that if the physical world was proved to be indeterministic this would provide an entry (interaction) point into the traditionally viewed closed system, where a scientifically described physically probable/improbable event could be philosophically described as an action of a non physical entity on physical reality.

Causal interaction

One argument against Dualism is with regard to causal interaction. If consciousness (the mind) can exist independently of physical reality (the brain), one must explain how physical memories are created concerning consciousness. Dualism must therefore explain how consciousness affects physical reality. One of the main objections to dualistic interactionism is lack of explanation of how the material and immaterial are able to interact. Varieties of dualism according to which an immaterial mind causally affects the material body and vice-versa have come under strenuous attack from different quarters, especially in the 20th century. Critics of dualism have often asked how something totally immaterial can affect something totally material - this is the basic problem of causal interaction.

First, it is not clear where the interaction would take place. For example, burning one's fingers causes pain. Apparently there is some chain of events, leading from the burning of skin, to the stimulation of nerve endings, to something happening in the peripheral nerves of one's body that lead to one's brain, to something happening in a particular part of one's brain, and finally resulting in the sensation of pain. But pain is not supposed to be spatially locatable. It might be responded that the pain "takes place in the brain." But, intuitively, pains are not located anywhere. This may not be a devastating criticism. However, there is a second problem about the interaction. Namely, the question of how the interaction takes place, where in dualism 'the mind' is assumed to be non physical and by definition outside of the realm of science. The mechanism which explains the connection between the mental and the physical would therefore be a philosophical proposition as compared to a scientific theory. For example, compare such a mechanism to a physical mechanism that is well understood. Take a very simple causal relation, such as when a cue ball strikes an eight ball and causes it to go into the pocket. What happens in this case is that the cue ball has a certain amount of momentum as its mass moves across the pool table with a certain velocity, and then that momentum is transferred to the eight ball, which then heads toward the pocket. Compare this to the situation in the brain, where one wants to say that a decision causes some neurons to fire and thus causes a body to move across the room. The intention to "cross the room now" is a mental event and, as such, it does not have physical properties such as force. If it has no force, then it would seem that it could not possibly cause any neuron to fire. However, with Dualism, an explanation is required of how something without any physical properties has physical effects.

By assuming a deterministic physical universe, the objection can be formulated more precisely. When a person decides to walk across a room, it is generally understood that the decision to do so, a mental event, immediately causes a group of neurons in that person's brain to fire, a physical event, which ultimately results in his walking across the room. The problem is that if there is something totally nonphysical causing a bunch of neurons to fire, then there is no physical event which causes the firing. This means that some physical energy is required to be generated against the physical laws of the deterministic universe - this is by definition a miracle and there can be no scientific explanation of (repeatable experiment performed regarding) where the physical energy for the firing came from. Such interactions would violate the fundamental laws of physics

Physical law

. In particular, if some external source of energy is responsible for the interactions, then this would violate the law of the conservation of energy

Conservation of energy

The nineteenth century law of conservation of energy is a law of physics. It states that the total amount of energy in an isolated system remains constant over time. The total energy is said to be conserved over time...

. Dualistic interactionism has therefore been argued against in that it violates a general heuristic

Heuristic

Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...

principle of science: the causal closure of the physical world.

Replies

Stanford Encyclopedia of Philosophy mentions two possible replies to this objection. The first reply says that it might be possible for mind to influence the distribution of energy, without altering its quantity. Another possibility is to deny that the human body is a closed system. Since the principle of conservation of energy applies only to closed systems, the objection becomes irrelevant. Catholic Encyclopedia mentions the same replies. These replies may protect The Law of Conservation of Energy, but they do not in themselves offer an explanation of how the interaction takes place (- it may be assumed to be a miracle).

Another reply to this objection is to assume some modification of causal relations in the physical universe - Mills has responded by pointing out that mental events may be causally overdetermined. Causal overdetermination means that some features of an effect may not be fully explained by its sufficient cause. For example, "the high pitched music caused the glass to break but this is the third time that that glass has broken in the last week." It is certain that the high-pitched music is the sufficient cause of the breaking of the glass, but it does not explain the feature of the event that is identified by the phrase "this is the third time this week...". That feature is causally related, in some sense, to the two prior events of the glasses having broken in the last week. In response, it has been pointed out that we should probably focus on the inherent or intrinsic features of situations or events, if they exist, and apply the idea of causal closure to just those specific features.

Another reply to this objection is that there is a possibility that the interaction may involve dark energy, dark matter or some other currently undefined scientific process, however in this case dualism is replaced with physicalism, or the interaction point is left for study at a later time when these physical processes are understood.

Another reply to this objection is made with respect to the derivation of an indeterministic physical universe, where perhaps the interaction which takes place in the human body is not at all of the classical "billiard ball" type of Newtonian mechanics. There is an important question of physical determinism

Determinism

Determinism is the general philosophical thesis that states that for everything that happens there are conditions such that, given them, nothing else could happen. There are many versions of this thesis. Each of them rests upon various alleged connections, and interdependencies of things and...

versus physical indeterminism

Indeterminism

Indeterminism is the concept that events are not caused, or not caused deterministically by prior events. It is the opposite of determinism and related to chance...

. If a non deterministic interpretation of quantum mechanics

Quantum mechanics

is correct then events at the microscopic level are necessarily indeterminate, where the degree of determinism increases as a function of the scale of the system (see Quantum decoherence

Quantum decoherence

In quantum mechanics, quantum decoherence is the loss of coherence or ordering of the phase angles between the components of a system in a quantum superposition. A consequence of this dephasing leads to classical or probabilistically additive behavior...

). One particular example of such indeterminism is Heisenberg's Uncertainty Principle

Uncertainty principle

In quantum mechanics, the Heisenberg uncertainty principle states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known...

, where the more precisely one can localize the position of an electron

Electron

The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

along an axis, the more imprecise becomes the ability to determine its linear momentum along this axis and vice-versa. Philosophers such as Karl Popper

Karl Popper

Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...

and John Eccles

John Carew Eccles

John Carew Eccles, AC FRS FRACP FRSNZ FAAS was an Australian neurophysiologist who won the 1963 Nobel Prize in Physiology or Medicine for his work on the synapse. He shared the prize with Andrew Huxley and Alan Lloyd Hodgkin....

have theorized that such indeterminacy may apply even at the macroscopic scale.

Argument from brain damage

This argument has been formulated by Paul Churchland

Paul Churchland

Paul Churchland is a philosopher noted for his studies in neurophilosophy and the philosophy of mind. He is currently a Professor at the University of California, San Diego, where he holds the Valtz Chair of Philosophy. Churchland holds a joint appointment with the Cognitive Science Faculty and...

, among others. The point is that, in instances of some sort of brain damage

Brain damage

"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...

(e.g. caused by automobile accidents, drug abuse, pathological diseases, etc.), it is always the case that the mental substance and/or properties of the person are significantly changed or compromised. If the mind were a completely separate substance from the brain, how could it be possible that every single time the brain is injured, the mind is also injured? Indeed, it is very frequently the case that one can even predict and explain the kind of mental or psychological deterioration or change that human beings will undergo when specific parts of their brains are damaged. So the question for the dualist to try to confront is how can all of this be explained if the mind is a separate and immaterial substance from, or if its properties are ontologically independent of, the brain. Property dualism

Property dualism

and William Hasker's

William Hasker

"emergent dualism" (which is largely similar to Vitalism

Vitalism

Vitalism, as defined by the Merriam-Webster dictionary, is#a doctrine that the functions of a living organism are due to a vital principle distinct from biochemical reactions...

) seek to avoid this problem. They assert that the mind is a property or substance that emerges from the appropriate arrangement of physical matter, and therefore could be affected by any rearrangement of matter.

Phineas Gage

Phineas Gage

Phineas P. Gage was an American railroad construction foreman now remembered for his improbablesurvival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and...

, who suffered destruction of one or both frontal lobes by a projectile iron rod, is often cited as an example illustrating that the brain causes mind. Gage certainly exhibited some mental changes after his accident. This physical event, the destruction of part of his brain, therefore caused some kind of change in his mind, suggesting a correlation between brain states and mental states. Similar examples abound; neuroscientist David Eagleman

David Eagleman

David Eagleman is a neuroscientist at Baylor College of Medicine, where he directs the Laboratory for Perception and Action and the Initiative on Neuroscience and Law. He is best known for his work on time perception, synesthesia, and neurolaw...

describes the case of another individual who exhibited escalating pedophilic tendencies at two different times, and in each case was found to have tumors growing in a particular part of his brain.

Case studies aside, modern experiments have demonstrated that the relation between brain and mind is much more than simple correlation. By damaging, or manipulating, specific areas of the brain repeatedly under controlled conditions (e.g. in monkeys) and reliably obtaining the same results in measures of mental state and abilities, neuroscientists have shown that the relation between damage to the brain and mental deterioration is likely causal. This conclusion is further supported by data from the effects of neuro-active chemicals (such as those affecting neurotransmitters) on mental functions, but also from research on Neurostimulation

Neurostimulation

Neurostimulation involves modulation of the nervous system and electrically activate neurons in the body. The activation of neural elements in a part of the nervous system can be effectively facilitated by stimulation. Micro-electrodes are utilized to interface with excitable tissue in order to...

(direct electrical stimulation of the brain, including Transcranial magnetic stimulation

Transcranial magnetic stimulation

Transcranial magnetic stimulation is a noninvasive method to cause depolarization or hyperpolarization in the neurons of the brain...

Argument from biological development

Another common argument against dualism consists in the idea that since human beings (both phylogenetically and ontogenetically) begin their existence as entirely physical or material entities and since nothing outside of the domain of the physical is added later on in the course of development, then we must necessarily end up being fully developed material beings. Phylogenetically, the human species evolved, as did all other species, from a single cell made up of matter. Since all the events that later occurred which ended up in the formation of our species can be explained through the processes of random mutation and natural selection, the difficulty for the dualist is to explain where and why there could have intervened some non-material, non-physical event in this process of natural evolution. Ontogenetically, we begin life as a simple fertilized ovum

Ovum

An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...

. There is nothing non-material or mentalistic involved in conception, the formation of the blastula

Blastula

The blastula is a hollow sphere of cells formed during an early stage of embryonic development in animals . The blastula is created when the zygote undergoes the cell division process known as cleavage. The blastula is preceded by the morula and is followed by the gastrula in the developmental...

, the gastrula, and so on. Our development can be explained entirely in terms of the accumulation of matter through the processes of nutrition

Nutrition

Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....

. The postulation of a non-physical mind would seem superfluous.

Argument from brain scans' ability to discern mental states

The decisions that a person makes can, in at least some contexts, be detected up to 10 seconds earlier by means of scanning their brain activity. Mental imagery can also be detected

Argument from simplicity

The argument from simplicity is probably the simplest and also the most common form of argument against dualism of the mental. The dualist is always faced with the question of why anyone should find it necessary to believe in the existence of two, ontologically distinct, entities (mind and brain), when it seems possible and would make for a simpler thesis to test against scientific evidence, to explain the same events and properties in terms of one. It is a heuristic principle in science and philosophy not to assume the existence of more entities than is necessary for clear explanation and prediction (see Occam's razor

Occam's razor

Occam's razor, also known as Ockham's razor, and sometimes expressed in Latin as lex parsimoniae , is a principle that generally recommends from among competing hypotheses selecting the one that makes the fewest new assumptions.-Overview:The principle is often summarized as "simpler explanations...

).

This argument was criticized by Peter Glassen

Peter Glassen

Peter Glassen was a professor of philosophy at the University of Manitoba from 1949 until his death in 1986. He was previously a member of the psychology department at the University of Saskatchewan. He developed a considerable reputation as an analytic moral philosopher on the basis of a number...

in a debate with J. J. C. Smart

J. J. C. Smart

John Jamieson Carswell "Jack" Smart AC is an Australian philosopher and academic who is currently Emeritus Professor of Philosophy at Monash University, Australia...

in the pages of Philosophy

Philosophy (journal)

Philosophy is the scholarly journal of the Royal Institute of Philosophy. It is designed to be intelligible to the non-specialist reader and has been in continuous publication for over 80 years. It is published by Cambridge University Press and is currently edited by Anthony O'Hear.-See also:* ...

in the late 1970s and early 1980s. Glassen argued that, because it is not a physical entity, Occam's Razor cannot consistently be appealed to by a physicalist or materialist as a justification of mental states or events, such as the belief that dualism is false. The idea is that Occam's razor may not be as 'unrestricted' as it is normally described (applying to all qualitative postulates, even abstract ones) but instead concrete (only applies to physical objects). If one applies Occam's Razor unrestrictedly, then it recommends monism until pluralism either receives more support, or until it is disproved. If one applies Occam's Razor only concretely, then it may not be used on abstract concepts (this route, however, has serious consequences for selecting between hypotheses about the abstract).

External links

Dualism in the online Dictionary of Philosophy of Mind
Dualism in the Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy
The Stanford Encyclopedia of Philosophy is a freely-accessible online encyclopedia of philosophy maintained by Stanford University. Each entry is written and maintained by an expert in the field, including professors from over 65 academic institutions worldwide...
Zombies in the Stanford Encyclopedia of Philosophy
Stanford Encyclopedia of Philosophy
The Stanford Encyclopedia of Philosophy is a freely-accessible online encyclopedia of philosophy maintained by Stanford University. Each entry is written and maintained by an expert in the field, including professors from over 65 academic institutions worldwide...
Mind and body, Rene Descartes to William James
Online Papers on Materialism and Dualism

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