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 foundations. Notable defenders of substance dualism include John Foster, Stewart Goetz, Richard Swinburne and Charles Taliaferro. Cartesian dualism, most famously defended by René Descartes, argues that there are two kinds of substances: mental and physical. Descartes states that the mental can exist outside of the body, and the body cannot think. Substance dualism is important historically for having given rise to much thought regarding the famous mind–body problem. It is compatible with theologies which claim that immortal souls occupy an independent realm of existence distinct from that of the physical world. The Copernican Revolution and the scientific discoveries of the 17th century reinforced the belief that the scientific method was the unique way of knowledge. Bodies were seen as biological organisms to be studied in their constituent parts (materialism) by means of anatomy, physiology, biochemistry and physics (reductionism). Mind–body dualism remained the biomedical paradigm and model for the following three centuries. Emergent dualism asserts that mental substances come into existence when physical systems such as the brain reach a sufficient level of complexity. He likens the individual mind to a magnetic field in its qualitative difference from the physical properties that generate it and also in its ability to act on the brain that generates it. Thomistic dualism Thomistic dualism is a type of dualism derived from the views of Thomas Aquinas. Edward Feser has written that: Thomistic substance dualism has been defended by J. P. Moreland and Scott B. Rae. Thomistic substance dualism distinguishes itself from Cartesian substance dualism by denying that the body and soul are different substances. Instead, a person is composed of only one substance, the soul, while the body is considered an ensouled physical structure. Other terms for Thomistic dualism include hylomorphic dualism or Thomistic hylomorphism which are contrasted with substance dualism. Hylomorphism is distinct from substance dualism as it holds the view that the immaterial (form) and material (matter) are not distinct substances and only share an efficient causality. Edward Feser who has defended hylomorphic dualism has suggested that it has advantages over substance dualism such as offering a possible solution to the interaction problem. Michael Egnor is a notable advocate of Aristotelian dualism. Property dualism Property dualism asserts that an ontological distinction lies in the differences between properties of mind and matter, and that consciousness may be 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. 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 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 expressed by Donald Davidson, where it is argued that mental events are identical to physical events, however, strict law-governed causal relationships cannot describe relations of mental events. Another argument for this has been expressed by John Searle, who is the advocate of a distinctive form of physicalism he calls biological naturalism. His view is that although mental states are ontologically irreducible to physical states, they are causally reducible. 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. Predicate dualism Predicate dualism is a view espoused by such non-reductive physicalists as Donald Davidson and Jerry Fodor, 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. Predicate dualism is most easily defined as the negation of predicate monism. Predicate monism can be characterized as the view subscribed to by eliminative materialists, 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. Predicate dualists believe that so-called "folk psychology," with all of its propositional attitude ascriptions, is an ineliminable part of the enterprise of describing, explaining, and understanding human mental states and behavior. For example, Davidson subscribes to anomalous monism, according to which there can be no strict psychophysical 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==

This part is about causation between properties and states of the thing under study, not its substances or predicates. Here a state is the set of all properties of what's being studied. Thus each state describes only one point in time. 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 logical 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. Jackson gave a subjective argument for epiphenomenalism, but later rejected it and embraced physicalism. Parallelism Psychophysical 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. 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, 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 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 itself. 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 Al-Ghazali, Louis de la Forge, Arnold Geulincx, and Nicolas Malebranche. Kantianism According to the philosophy of Immanuel Kant, there is a distinction between actions done by desire and those performed by reason in liberty (categorical imperative). Thus, not all physical actions are caused either by matter alone or by freedom alone. Some actions are purely animal in nature, while others are the result of mind's free action on matter. ==History==

Ancient Greek philosophy Hermotimus of Clazomenae (fl. c. 6th century BCE) was a philosopher who first proposed the idea of mind being fundamental in the cause of change. He proposed that physical entities are static, while reason causes the change. Sextus Empiricus places him with Hesiod, Parmenides, and Empedocles, as belonging to the class of philosophers who held a dualistic theory of a material and an active principle being together the origin of the universe. Similar ideas were expounded by Anaxagoras. In the dialogue Phaedo, Plato formulated his famous Theory of forms as distinct and immaterial substances of which the objects and other phenomena that we perceive in the world are nothing more than mere shadows. From Neoplatonism to scholasticism The philosophical school of Neoplatonism, most active in late antiquity, claimed that the physical and the spiritual are both emanations of the One. Neoplatonism exerted a considerable influence on Christianity, as did the philosophy of Aristotle via scholasticism. In the scholastic tradition of Saint Thomas Aquinas, a number of whose doctrines have been incorporated into Roman Catholic dogma, the soul is the substantial form of a human being. Aquinas held the Quaestiones disputate de anima, or 'Disputed questions on the soul', at the Roman studium provinciale of the Dominican Order at Santa Sabina, the forerunner of the Pontifical University of Saint Thomas Aquinas, Angelicum during the academic year 1265–1266. By 1268 Aquinas had written at least the first book of the Sententia Libri De anima, Aquinas' commentary on Aristotle's De anima, the translation of which from the Greek was completed by Aquinas' Dominican associate at Viterbo, William of Moerbeke in 1267. Like Aristotle, Aquinas held that the human being was a unified composite substance of two substantial principles: form and matter. The soul is the substantial form and so the first actuality of a material organic body with the potentiality for life. While Aquinas defended the unity of human nature as a composite substance constituted by these two inextricable principles of form and matter, he also argued for the incorruptibility of the intellectual soul, Hence, Aquinas held 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 doctrine of the resurrection of the body does not subscribe that, sees body and soul as forming a whole and states that at the second coming, the souls of the departed will be reunited with their bodies as a whole person (substance) and witness to the apocalypse. The thorough consistency between dogma and contemporary science was maintained here in part from a serious attendance to the principle that there can be only one truth. Consistency with science, logic, philosophy, and faith 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 upon death of the body. Eastern Philosophy Early Chinese thought is often described as non-dualistic, but Slingerland and Chudek (2011) show that there are multiple classical texts that make clear distinctions between mental and physical processes. Their analysis of these texts suggests that certain forms of dualistic thinking were present in early Chinese traditions. Some interpretations of Buddhist philosophy describe the mind and body as interdependent. Lin (2013) argues that classical buddhist texts do not support a strong separation between the mind and the body, but rather treat consciousness as something that comes from a mix of physical, cognitive, and environmental conditions. Descartes and his disciples In his Meditations on First Philosophy, René Descartes embarked upon a quest in which he called all his previous beliefs into doubt, to find out what he could be certain of. The central claim of what is often called Cartesian dualism, in honor of Descartes, is that the immaterial mind and the material body, while being ontologically distinct substances, causally interact. This is an idea that 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, he suggested that spirits interacted with the body through the pineal gland, a small gland in the centre of the brain, between the two hemispheres. Mind-Body Dualism in Medicine In pain research, some scholars argue that splitting pain into "physical" versus "psychological" types reflects outdated dualistic thinking. Williams and Craig (2016) suggest that pain is influenced by biological, emotional, and social factors at the same time and treating them as separate can lead to poor care. They emphasize that effective pain management requires a holistic approach that considers how these dimensions work together, which highlights how focusing exclusively on the physical or psychological aspects may cause one to miss certain factors affecting a patient's experience. Cultural beliefs about the causes of illness also show how dualism still plays a role in modern health attitudes. Tayeb (2019) studied public views about epilepsy in Saudi Arabia and found that people who connected epilepsy to spiritual or psychological causes were more likely to hold a stigmatized attitude towards the condition compared to those who viewed it as a neurological disorder. The study underscores how cultural frameworks of mind-body causation not only affect personal beliefs but also can have an effect on systemic barriers, such as a reluctance to perform treatment or even delay diagnosis. Hane (2019) discusses the role of dualism in modern psychiatry. Instead of defending the strict separation between the mind and body, he emphasizes that mental and physical explanations offer different ways of understanding the same experience and often complement each other. Dualist ideas continue to shape clinical practices, influence how doctors diagnose patients, and guide treatment. Even when explicitly acknowledged, this affects both the practice of psychiatry and how patients experience mental distress. In psychiatry, debates on the mind-body problem continue to influence how mental disorders are understood. Van Oudenhove and Cuypers (2010) argue that even as neuroscience advances, the underlying assumption that the mind is separate from the brain still shapes theory, diagnosis, and treatment. In Cognitive Science Research in cognitive anthropology shows that many cultures naturally treat the mind as something that can exist separately from the body. Cohen and Barret (2008) found this to be true in beliefs about spirits and possession, where people imagine minds or souls moving independently from the physical body. These cultural models suggest that seeing the mind and body as separate entities is not only a philosophical idea, rather it is something that influences how people experience everyday life. Developmental research also suggests that children tend to see the mind, body, and soul as different things. Richert and Harris (2008) found that young children often treat mental abilities and spiritual qualities as separate from the physical body, supporting the idea that dualistic thinking starts early in life. For instance, children may believe that thoughts or feelings could continue even if someone is no longer living or that a person's soul can inhabit a different body or object. Recent In addition to already discussed theories of dualism (particularly the Christian and Cartesian models) there are new theories in the defense of dualism. Naturalistic dualism comes from Australian philosopher, David Chalmers (born 1966) who argues there is an explanatory gap between objective and subjective experience that cannot be bridged by reductionism because consciousness is, at least, logically autonomous of the physical properties upon which it supervenes. According to Chalmers, a naturalistic account of property dualism requires a new fundamental category of properties described by new laws of supervenience; the challenge being analogous to that of understanding electricity based on the mechanistic and Newtonian models of materialism prior to Maxwell's equations. A similar defense comes from Australian philosopher Frank Jackson (born 1943) who revived the theory of epiphenomenalism which argues that mental states do not play a role in physical states. Jackson argues that there are two kinds of dualism: • substance dualism that assumes there is second, non-corporeal form of reality. In this form, body and soul are two different substances. • property dualism that says that body and soul are different properties of the same body. He claims that functions of the mind/soul are internal, very private experiences that are not accessible to observation by others, and therefore not accessible by science (at least not yet). We can know everything, for example, about a bat's facility for echolocation, but we will never know how the bat experiences that phenomenon. In 2018, The Blackwell Companion to Substance Dualism was published that contains arguments for and against Cartesian dualism, emergent dualism, Thomistic dualism, emergent individualism and nonreductive physicalism. Contributors include Charles Taliaferro, Edward Feser, William Hasker, J. P. Moreland, Richard Swinburne, Lynne Rudder Baker, John W. Cooper and Timothy O'Connor. ==Arguments for dualism==

The subjective argument An important fact is that minds perceive intra-mental states differently from sensory phenomena, and this cognitive difference results in mental and physical phenomena having seemingly disparate properties. The subjective argument holds that these properties are irreconcilable under a physical mind. Mental events have a certain subjective quality to them, whereas physical ones 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. 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 cannot be reduced to anything physical. Frank Jackson formulated his well-known knowledge argument based upon similar considerations. In this thought experiment, known as Mary's room, 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 Mary knows everything there is to know about colours from an objective, third-person perspective, she has never known, 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 about the physical aspects of colour. However, Jackson later rejected his argument and embraced physicalism. He notes that Mary obtains knowledge not of color, but of a new intramental state, seeing color. Daniel Dennett and others also provide arguments against this notion. The zombie argument The zombie argument is based on a thought experiment proposed by David Chalmers over the issue of qualia or the hard problem of consciousness. The basic idea is that one can imagine, and, therefore, conceive the existence of, an apparently functioning human being/body without any conscious states being associated with it. Chalmers' argument is that it seems plausible that such a being could exist because all that is needed is that all and only the things that the physical sciences describe and observe about a human being must be true of the zombie. None of the concepts involved in these sciences make reference to consciousness or other mental phenomena, and any physical entity can be described scientifically via physics whether it is conscious or not. The mere logical possibility of a p-zombie demonstrates that consciousness is a natural phenomenon beyond the current unsatisfactory explanations. Chalmers states that one probably could not build a living p-zombie because living things seem to require a level of consciousness. However (unconscious?) robots built to simulate humans may become the first real p-zombies. Hence Chalmers half-jokingly calls for the need to build a "consciousness meter" to ascertain if any given entity, human or robot, is conscious or not. 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, 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. Avshalom Elitzur has described himself as a "reluctant dualist". One argument Elitzur makes in favor of dualism is an argument from bafflement. According to Elitzur, a conscious being can conceive of a P-zombie version of his/herself. However, a P-zombie cannot conceive of a version of itself that lacks corresponding qualia. Special sciences argument Howard Robinson argues that, if predicate dualism is correct, then there are "special sciences" that are irreducible to physics. These allegedly irreducible subjects, which contain irreducible predicates, differ from hard sciences in that they are interest-relative. Here, interest-relative fields depend on the existence of minds that can have interested perspectives. and psychology do not require the mind to be irreducible, and operate on the assumption that it has physical basis. In fact, it is common in science to presuppose a complex system; while fields such as chemistry, biology, or geology could be verbosely expressed in terms of quantum field theory, it is convenient to use levels of abstraction like molecules, cells, or the mantle. It is often difficult to decompose these levels without heavy analysis and computation. Sober has also advanced philosophical arguments against the notion of irreducibility. 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. 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: A possible solution to this dilemma is that of open individualism. Richard Swinburne, in his book The Existence of God, put forward an argument for mind-body dualism based upon personal identity. He states that the brain is composed of two hemispheres and a cord linking the two and that, as modern science has shown, either of these can be removed without the person losing any memories or mental capacities. He then cites a thought-experiment for the reader, asking what would happen if each of the two hemispheres of one person were placed inside two different people. Either, Swinburne claims, one of the two is me or neither is—and there is no way of telling which, as each will have similar memories and mental capacities to the other. In fact, Swinburne claims, even if one's mental capacities and memories are far more similar to the original person than the others' are, they still may not be him. From here, he deduces that even if we know what has happened to every single atom inside a person's brain, we still do not know what has happened to 'them' as an identity. From here it follows that a part of our mind, or our soul, is immaterial, and, as a consequence, that mind-body dualism is true. Christian List argues that Benj Hellie's vertiginous question, i.e. why people exist as themselves and not as someone else, and the existence of first-personal facts, are a refutation of physicalist philosophies of consciousness. List argues that first personal facts cannot supervene on third personal facts. However, List also argues that this also refutes standard versions of mind-body dualism that have purely third-personal metaphysics. Argument from reason Philosophers and scientists such as Victor Reppert, William Hasker, and Alvin Plantinga have developed an argument for dualism dubbed the "argument from reason". They credit C. S. Lewis with first bringing the argument to light in his book Miracles; Lewis called the argument "The Cardinal Difficulty of Naturalism", which was the title of chapter three of Miracles. The argument postulates that if, as 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. However, knowledge is apprehended by reasoning from ground to consequent. Therefore, if naturalism were true, there would be no way of knowing it (or anything else), except by a fluke. That is, to conclude its truth would eliminate the grounds from which to reach it. To summarize the argument in the book, Lewis quotes J. B. S. Haldane, who appeals to a similar line of reasoning: In his essay "Is Theology Poetry?", Lewis himself summarises the argument in a similar fashion when he writes: But Lewis later agreed with Elizabeth Anscombe's response to his Miracles argument. She showed that an argument could be valid and ground-consequent even if its propositions were generated via physical cause and effect by non-rational factors. Similar to Anscombe, Richard Carrier and John Beversluis have written extensive objections to the argument from reason on the untenability of its first postulate. Cartesian arguments Descartes puts forward two main arguments for dualism in Meditations: firstly, the "modal argument," or the "clear and distinct perception argument," and secondly the "indivisibility" or "divisibility" argument. The argument is distinguished from the Zombie Argument as it establishes that the mind could continue to exist without the body, rather than that the unaltered body could exist without the mind. Alvin Plantinga, J. P. Moreland, and Edward Feser have both supported the argument, although Feser and Moreland think that it must be carefully reformulated to be effective. The indivisibility argument for dualism was phrased by Descartes as follows:[T]here is a great difference between a mind and a body, because the body, by its very nature, is something divisible, whereas the mind is plainly indivisible...insofar as I am only a thing that thinks, I cannot distinguish any parts in me.... Although the whole mind seems to be united to the whole body, nevertheless, were a foot or an arm or any other bodily part amputated, I know that nothing would be taken away from the mind...The argument relies upon Leibniz' principle of the identity of indiscernibles, which states that two things are the same if and only if they share all their properties. A counterargument is the idea that matter is not infinitely divisible, and thus that the mind could be identified with material things that cannot be divided, or potentially Leibnizian monads. ==Arguments against dualism==

Arguments from 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 finger 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 evidently, the pain is in the finger. 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. More recent philosophical work has revisited the issue of how a non-physical mind could affect a physical body. Tiehen (2016) argues that because modern science assumes the physical world is "causally closed," it becomes difficult for dualism to explain how the mind could play a causal role without breaking this principle. This problem led some philosophers to suggest alternate frameworks to explain how mental states might influence bodily processes without breaking any physical laws. Replies Alfred North Whitehead, and later David Ray Griffin, framed a new ontology (process philosophy) seeking precisely to avoid the pitfalls of ontological dualism. The explanation provided by Arnold Geulincx and Nicolas Malebranche is that of occasionalism, where all mind–body interactions require the direct intervention of God. At the time C. S. Lewis wrote Miracles, quantum mechanics (and physical indeterminism) was only in the initial stages of acceptance, but still Lewis 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. He states, however, that none of the arguments in his book will rely on this. Although some interpretations of quantum mechanics consider wave function collapse to be indeterminate, in others this event is defined as deterministic. Argument from physics The argument from physics is closely related to the argument from causal interaction. Many physicists and consciousness researchers have argued that any action of a nonphysical mind on the brain would entail the violation of physical laws, such as the conservation of energy. 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 non-physical 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. In particular, if some external source of energy is responsible for the interactions, then this would violate the law of the conservation of energy. Dualistic interactionism has therefore been criticized for violating a general heuristic principle of science: the causal closure of the physical world. Replies The Stanford Encyclopedia of Philosophy provide two possible replies to the above objections. The first reply is that the mind may influence the distribution of energy, without altering its quantity. The second possibility is to deny that the human body is causally closed, as the conservation of energy applies only to closed systems. However, physicalists object that no evidence exists for the causal non-closure of the human body. Robin Collins responds that energy conservation objections misunderstand the role of energy conservation in physics. Well understood scenarios in general relativity violate energy conservation and quantum mechanics provides precedent for causal interactions, or correlation without energy or momentum exchange. However, this does not mean the mind spends energy and, despite that, it still doesn't exclude the supernatural. Another reply is akin to parallelism—Mills holds that behavioral events are causally overdetermined, and can be explained by either physical or mental causes alone. An overdetermined event is fully accounted for by multiple causes at once. However, J. J. C. Smart and Paul Churchland have pointed out that if physical phenomena fully determine behavioral events, then by Occam's razor an unphysical mind is unnecessary. Howard Robinson suggests that the interaction may involve dark energy, dark matter or some other currently unknown scientific process. However, Max Tegmark has argued that classical and quantum calculations show that quantum decoherence effects do not play a role in brain activity. Yet another reply to the interaction problem is to note that it doesn't seem that there is an interaction problem for all forms of substance dualism. For instance, Thomistic dualism doesn't obviously face any issue with regards to interaction, for in this view the soul and the body are related as form and matter. Argument from brain damage This argument has been formulated by Paul Churchland, among others. The point is that, in instances of some sort of brain damage (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. Phineas Gage, 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, suggesting a correlation between brain states and mental states. It has been noted, however, that Gage's most serious mental changes were only temporary, and that he made a reasonable social and mental recovery. The changes in question have almost always been distorted and exaggerated by scientific and popular literature, often relying on hearsay. Similar examples abound; neuroscientist David Eagleman 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 (e.g., those affecting neurotransmitters) on mental functions, but also from research on neurostimulation (direct electrical stimulation of the brain, including transcranial magnetic stimulation). Replies Property dualism and William Hasker's "emergent dualism" 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. Writing in the 13th century, St. Thomas Aquinas writes that "the body is necessary for the action of the intellect, not as origin of action." Thus, if the body is dysfunctional, the intellect will not actualize as it intends to. According to the philosopher Stephen Evans: Argument from neuroscience In some contexts, the decisions that a person makes can be detected up to 10 seconds in advance by means of scanning their brain activity. Subjective experiences and covert attitudes can be detected, as can mental imagery. This is cited as empirical evidence that cognitive processes have a physical basis in the brain. Some recent work in robotics and artificial intelligence has also found issues with traditional dualistic ideas. Sandini, Scuitti, and Morasso (2024) argue that intelligent behavior depends on how a body interacts with the environment, and that purely abstract forms of artificial intelligence may miss key parts of what makes natural cognition possible. This highlights the importance of sensorimotor experiences and attempts made to replicate human intelligence in machines need to consider physical embodiment and adaptive learning instead of just relying on abstract computational models. Replies Thomist philosopher Edward Feser criticises the use of neuroscience to support a naturalist account of the mind, drawing from philosopher Tyler Burge in calling such arguments "neurobabble." Feser accepts that neural activities underlie mental processes, but that this is to be expected from the view of hylomorphic dualism, since the soul is a composite of mind and matter. 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. Replies This argument was criticized by Peter Glassen in a debate with J. J. C. Smart in the pages of Philosophy 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 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). This argument has also been criticized by Seyyed Jaaber Mousavirad, who argues that the principle of simplicity could only be applied when there is no need for an additional entity. Despite arguments indicating the need for the soul, the principle of simplicity does not apply. Therefore, if there were no argument establishing the existence of the soul, one could deny its existence based on the principle of simplicity. However, various arguments have been put forth to establish its existence. These arguments demonstrate that while neuroscience can explain the mysteries of the material brain, certain significant issues, such as personal identity and free will, remain beyond the scope of neuroscience. The crux of the matter lies in the essential limitations of neuroscience and the potency of substance dualism in explaining these phenomena. ==See also==