View source for Mind–body dualism

{{Short description|Philosophical theory}}
{{Use dmy dates|date=November 2019}}

[[File:Descartes mind and body.gif|thumb|200px|right|Illustration of mind–body dualism by [[René Descartes]]. Inputs are passed by the sensory organs to the [[pineal gland]], and from there to the immaterial [[Soul|spirit]].]]

{{Philosophy sidebar}}

In the [[philosophy of mind]], '''mind–body dualism''' denotes either that [[mind|mental]] phenomena are [[non-physical entity|non-physical]],<ref name="Hart">[[W. D. Hart|Hart, W. D.]] 1996. "Dualism." pp. 265–267 in ''A Companion to the Philosophy of Mind'', edited by [[Samuel Guttenplan|S. Guttenplan]]. Oxford: Blackwell.</ref> or that the [[mind]] and [[Human body|body]] are distinct and separable.<ref name="Crane2001p1">{{cite book |last1=Crane |first1=Tim |last2=Patterson |first2=Sarah |year=2001 |title=History of the Mind-Body Problem |chapter=Introduction |pages=1–2 |quote=the assumption that mind and body are distinct (essentially, dualism)}}</ref> Thus, it encompasses a set of views about the relationship between mind and matter, as well as between [[subject (philosophy)|subject]] and [[object (philosophy)|object]], and is contrasted with other positions, such as [[physicalism]] and [[enactivism]], in the [[mind–body problem]].<ref name="Hart" /><ref name="Crane2001p1" />

[[Aristotle]] shared [[Plato]]'s view of multiple [[Soul (spirit)|souls]] and further elaborated a hierarchical arrangement, corresponding to the distinctive functions of plants, animals, and humans: a nutritive soul of growth and [[metabolism]] that all three share; a perceptive soul of pain, pleasure, and desire that only humans and other animals share; and the faculty of reason that is unique to humans only. In this view, a soul is the [[hylomorphism|hylomorphic form]] of a viable organism, wherein each level of the hierarchy formally [[supervenience|supervenes]] upon the [[substance theory|substance]] of the preceding level. For Aristotle, the first two souls, based on the body, perish when the living organism dies,<ref name="Ari2" /><ref name="Ari1">Aristotle. [c. mid 4th century BC] 1924. ''[[Metaphysics (Aristotle)|Metaphysics (Metaphysica)]]'', edited by W. D. Ross. Oxford: Oxford University Press, 2 vols.{{Bulleted list|1971. Books IV-VI, trans. C. A. Kirwan, Clarendon Aristotle Series. Oxford: Oxford University Press;|1976. Books XIII–XIV trans. J. Annas, Clarendon Aristotle Series, Oxford: Oxford University Press;|1994. Books VII-VIII trans. D. Bostock, Clarendon Aristotle Series, Oxford: Oxford University Press.}}</ref> whereas there remains an immortal and perpetual intellective part of mind.<ref>Aristotle, ''[[On the Soul|De Anima]]'' III:{{Bulleted list|"For whereas the sensitive faculty is not found apart from the body, the intellect is separate." (4, 429b3)|"When mind is set free from its present conditions it appears as just what it is and nothing more: this alone is immortal and eternal." (5, 430a22)}}</ref> For Plato, however, the soul was not dependent on the physical body; he believed in [[metempsychosis]], the migration of the soul to a new physical body.<ref name="Plat">Duke, E. A., W. F. Hicken, W. S. M. Nicoll, et al., eds. 1995. ''Platonis Opera, Vol. 1: Tetralogiae I-II'', [[Oxford Classical Texts]].  Oxford: Clarendon Press. {{doi|10.1093/actrade/9780198145691.book.1}}. (includes ''[[Euthyphro]]'', ''[[Apologia Sokratous|Apologia Socratis]]'', ''[[Crito]]'', ''[[Phaedo]]'', ''[[Cratylus (dialogue)|Cratylus]]'', ''[[Theaetetus (dialogue)|Theaetetus]]'', ''[[Sophist (dialogue)|Sophistes]]'', and ''[[Politicus]]''.)</ref> It has been considered a form of reductionism by some philosophers, since it enables the tendency to ignore very big groups of variables by its assumed association with the mind or the body, and not for its real value when it comes to explaining or predicting a studied phenomenon.<ref>{{cite journal|title=Reductionism in Biology|journal=Stanford Encyclopedia of Philosophy|year=2017|url=https://plato.stanford.edu/entries/reduction-biology/}}</ref>

Dualism is closely associated with the thought of [[René Descartes]] (1641), who holds that the mind is a nonphysical—and therefore, non-spatial—substance. Descartes clearly identified the mind with [[consciousness]] and self-awareness and distinguished this from the physical brain as the seat of [[intelligence]].<ref name="SEP">[[Howard Robinson|Robinson, Howard]]. [2003] 2016. "[http://plato.stanford.edu/entries/dualism/ Dualism]" (rev.). ''[[Stanford Encyclopedia of Philosophy|The Stanford Encyclopedia of Philosophy]]'', edited by [[Edward N. Zalta]].</ref> Hence, he was the first documented Western philosopher to formulate the mind–body problem in the form in which it exists today.<ref name="De">[[René Descartes|Descartes, René]]. [1641] 1984. "[[Meditations on First Philosophy]]." pp. 1–62 in ''The Philosophical Writings of René Descartes'' 2, translated by J. Cottingham, R. Stoothoff, and D. Murdoch. Cambridge: Cambridge University Press.</ref> However, the theory of substance dualism has many advocates in contemporary philosophy such as [[Richard Swinburne]], William Hasker, [[J. P. Moreland]], E. J. Low, [[Charles Taliaferro]], Seyyed Jaaber Mousavirad, and John Foster.<ref>{{Cite journal |last1=Mousavirad |first1=Seyyed Jaaber |last2=Philosophy Documentation Center |date=2023 |title=Coherence of Substance Dualism |url=https://www.pdcnet.org/oom/service?url_ver=Z39.88-2004&rft_val_fmt=&rft.imuse_id=ipq_2023_0063_0001_0033_0042&svc_id=info:www.pdcnet.org/collection |journal=International Philosophical Quarterly |volume=63 |issue=1 |pages=33–42 |doi=10.5840/ipq20231114214 |issn=0019-0365|url-access=subscription }}</ref>

Dualism is contrasted with various kinds of [[monism]]. [[#Substance dualism|Substance dualism]] is contrasted with all forms of [[materialism]], but [[property dualism]] may be considered a form of [[non-reductive physicalism]].

==Types==
[[Ontology|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.<ref name="Hart" />
# ''[[Property dualism]]'' suggests that the ontological distinction lies in the differences between properties of mind and matter (as in [[emergentism]]).<ref name="Hart" />
# ''[[Predicate dualism]]'' claims the irreducibility of mental predicates to physical predicates.<ref name="Hart" />

==={{Anchor|Substance dualism|Cartesian dualism}}Substance or Cartesian dualism<!-- 'Substance dualism', 'Substance Dualism', 'Cartesian dualism', and 'Cartesian Dualism' redirect here. -->===
'''Substance dualism''' asserts that mind and matter are fundamentally distinct kinds of foundations. There are different types of substance dualism. Most substance dualists hold the view that the mind and body are capable of causally affecting each other, known as [[Interactionism (philosophy of mind)|interactionism]].<ref>{{Cite web|author=Calef, Scott|date=2024|title=Dualism and Mind|url=https://iep.utm.edu/dualism-and-mind/|website=Internet Encyclopedia of Philosophy|language=en-GB|archive-date=June 23, 2024|archive-url=https://web.archive.org/web/20240623215936/https://iep.utm.edu/dualism-and-mind/|url-status=live}}</ref> Notable defenders of substance dualism include [[John Foster (philosopher)|John Foster]], [[Stewart Goetz]], [[Richard Swinburne]] and [[Charles Taliaferro]].<ref name="Mousavirad 2023">{{Cite journal |last1=Mousavirad |first1=Seyyed Jaaber |last2=Philosophy Documentation Center |date=2023 |title=Coherence of Substance Dualism |url=https://www.pdcnet.org/oom/service?url_ver=Z39.88-2004&rft_val_fmt=&rft.imuse_id=ipq_2023_0063_0001_0033_0042&svc_id=info:www.pdcnet.org/collection |journal=International Philosophical Quarterly |volume=63 |issue=1 |pages=41–42 |doi=10.5840/ipq20231114214 |s2cid=265269649 |issn=0019-0365|url-access=subscription }}</ref><ref>{{cite journal|author=Swinburne, Richard|year=1996|title=Dualism Intact|journal=Faith and Philosophy: Journal of the Society of Christian Philosophers|url=https://place.asburyseminary.edu/faithandphilosophy/vol13/iss1/4/|volume=13|issue=1|pages=68–77|doi=10.5840/faithphil199613116}}</ref><ref>{{cite journal|author=Givens, Terryl L.|year=2012|title=Reviewed Work: A Brief History of the Soul by Stewart Goetz, Charles Taliaferro|journal=Church History|volume=81|issue=3|pages=656–658|doi=10.1017/S0009640712001357 |jstor=23252345}}</ref><ref>Taliaferro, Charles. (2018). ''Substance Dualism: A Defense''. In Jonathan J. Loose, Angus John Louis Menuge & J. P. Moreland. ''The Blackwell Companion to Substance Dualism''. Wiley-Blackwell. pp. 41–60</ref>

Cartesian dualism, most famously defended by [[René Descartes]], argues that there are two kinds of substances: mental and physical.<ref name="SEP"/><ref>{{Cite web|date=2016|title=Cartesian dualism|url=https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095552351|website=Oxford Reference|language=en-GB}}</ref> 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.<ref name="Hart"/> Cartesians tend to equate the soul to the mind.<ref name="Moreland 2010">{{cite journal|author=Moreland, J. P.|year=2010|title=The Origin of the Soul in Light of Twinning, Cloning, and Frozen Etnbryos|journal=Journal of the International Society of Christian Apologetics|url=https://theologicalstudies.org.uk/pdf/jisca/03-1_001.pdf|volume=3|issue=1|pages=1–12}}</ref>

The [[Heliocentrism|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).<ref name="PMC_3115289">{{cite journal|first1=Neeta|last1=Mehta|title=Mind-body Dualism: A critique from a Health Perspective|journal=Mens Sana Monogr.|year=2011|volume=9|issue=1|pages=202–209|pmid= 21694971|pmc=3115289|doi=10.4103/0973-1229.77436|doi-broken-date=12 July 2025 |oclc= 8663197050|issn=0973-1229|doi-access=free}}</ref> Mind–body dualism remained the biomedical paradigm and model for the following three centuries.<ref name="PMC_3115289"/>

===Emergent dualism===

Emergent dualism is a type of substance dualism that has been defended by [[William Hasker]] and [[Dean Zimmerman (philosopher)|Dean Zimmerman]].<ref>{{cite journal|author=Baker, Lynne Rudder|year=2002|title=Reviewed Work: The Emergent Self William Hasker|journal=Philosophy and Phenomenological Research|volume=65|issue=3|pages=734–736|jstor=3071148}}</ref><ref name="Dilley 2003">{{cite journal|author=Dilley, Frank B.|year=2003|title=A Critique of Emergent Dualism|journal=Faith and Philosophy: Journal of the Society of Christian Philosophers|url=https://place.asburyseminary.edu/cgi/viewcontent.cgi?article=1914&context=faithandphilosophy|volume=20|issue=1|pages=37–49|doi=10.5840/faithphil200320114}}</ref><ref>Hasker, William. (2018). ''The Case for Emergent Dualism''. In Jonathan J. Loose, Angus J. L. Menuge, J. P. Moreland. ''The Blackwell Companion to Substance Dualism''. Wiley-Blackwell. pp. 61–72. {{ISBN|978-1119375265}}</ref><ref name="Spackman 2013">{{cite journal|author=Spackman, John|year=2013|title=Consciousness and the Prospects for Substance Dualism|journal=Philosophy Compass|url=https://www.newdualism.org/papers/J.Spackman/Spackman-PhilComp2013.pdf|volume=8|issue=11|pages=1054–106|doi=10.1111/phc3.12009|archive-url=https://web.archive.org/web/20240411145024/https://www.newdualism.org/papers/J.Spackman/Spackman-PhilComp2013.pdf |archive-date=11 April 2024 }}</ref> Emergent dualism asserts that mental substances come into existence when physical systems such as the brain reach a sufficient level of complexity.<ref name="Spackman 2013"/> Hasker defines emergent dualism as:

{{blockquote|Human persons are not identical to any physical body, but consist of a physical body and a non-physical substantial soul, and (b) the human soul is naturally
emergent from and dependent on the structure and function of a living human brain and nervous system.<ref>Rickabaugh, Brandon L. [https://philarchive.org/archive/RICAED-2 ''Against Emergent Dualism'']. In Jonathan J. Loose, Angus J. L. Menuge, J. P. Moreland. (2018). ''The Blackwell Companion to Substance Dualism''. Wiley-Blackwell. {{ISBN|978-1119375265}}</ref>}}

Hasker has argued that emergent dualism is consistent with neuroscientific discoveries showing the dependence of mind on brain.<ref name="Dilley 2003"/><ref>{{cite journal|author=Gasparov, Ignor|year=2013|title=Substance Dualism and the Unity of Consciousness|journal=Forum Philosophicum|url=https://forumphilosophicum.ignatianum.edu.pl/docannexe/file/5420/7_gasparov.pdf|volume=18|issue=1|pages=109–123|doi=10.35765/forphil.2013.1801.07 |archive-url=https://web.archive.org/web/20230615133655/https://forumphilosophicum.ignatianum.edu.pl/docannexe/file/5420/7_gasparov.pdf |archive-date=15 June 2023 }}</ref> 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.<ref name="Dilley 2003"/> Consciousness is said to arise when the brain reaches a certain threshold level of organizational complexity and when properly organized gives rise to the soul.<ref>{{cite journal|author=Hershenov, David B; Taylor, Adam P.|year=2014|title=Split brains: no headache for the soul theorist|journal=Religious Studies|url=|volume=50|issue=4|pages=487–503|doi=10.1017/S0034412514000109 |jstor=43670546}}</ref>

===Thomistic dualism===

Thomistic dualism is a type of dualism derived from the views of [[Thomas Aquinas]].<ref name="Feser 2005">{{cite book |last=Feser |first=Edward |date=2006 |title=Philosophy of Mind: A Beginner's Guide |url=https://library.ucaphil.online/assets/files/Philosophy-ofMind-Feser.pdf |url-status= |pages=221–228| publisher=Oneworld Publications |isbn=978-1851684786|archive-url=https://web.archive.org/web/20240927010324/https://library.ucaphil.online/assets/files/Philosophy-ofMind-Feser.pdf |archive-date=September 27, 2024}}</ref> [[Edward Feser]] has written that:

{{blockquote|Aristotelians and Thomists (those philosophers whose views are derived from St.Thomas Aquinas) sometimes suggest that their hylomorphic position is no more a version of dualism than it is of materialism. But though their view is not a Cartesian form of dualism, it is clear from a consideration of how the human soul differs from the souls of plants and animals (at least on the Thomistic variation of hylomorphism) that the view does amount to a kind of dualism: Thomistic dualism or hylomorphic dualism, as it has variously been called.<ref name="Feser 2005"/>}}

[[Thomism|Thomistic]] substance dualism has been defended by [[J. P. Moreland]] and [[Scott B. Rae]].<ref>{{cite journal|author=Reichenbach, Bruce R.|year=2002|title=J. P. Moreland & Scott B. Rae, Body and Soul: Human Nature and the Crisis in Ethics|journal=Faith and Philosophy: Journal of the Society of Christian Philosophers|url=https://place.asburyseminary.edu/cgi/viewcontent.cgi?article=1883&context=faithandphilosophy|volume=19|issue=1|pages=112–116|doi=10.5840/faithphil200219112}}</ref><ref name="Van Dyke 2009">{{cite journal|author=Van Dyke, Christina|year=2009|title=Not Properly a Person: The Rational Soul and 'Thomistic Substance Dualism'|journal=Faith and Philosophy|url=https://www.pdcnet.org/faithphil/content/faithphil_2009_0026_0002_0186_0204|volume=26|issue=2|pages=186–204|doi=10.5840/faithphil200926226|url-access=subscription}}</ref> 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.<ref name="Van Dyke 2009"/> J. P. Moreland has commented:

{{blockquote|Thomistic substance dualism is not a dualism of two separable substances. There is only one substance, though I do not identify it with the body/soul composite. Rather, I take the one substance to be the soul, and the body to be an ensouled biological and physical structure that depends on the soul for its existence.<ref name="Moreland 2010"/>}}

[[Eleonore Stump]] has suggested that [[Thomas Aquinas]]'s views on matter and the soul are difficult to define in contemporary discussion but he would fit the criteria as a non-Cartesian substance dualist.<ref>{{cite journal|author=Stump, Eleonore|year=1995|title=Non-Cartesian Substance Dualism and Materialism Without Reductionism|journal=Faith and Philosophy: Journal of the Society of Christian Philosophers|url=https://place.asburyseminary.edu/cgi/viewcontent.cgi?article=1552&context=faithandphilosophy|volume=12|issue=4|pages=505–531|doi=10.5840/faithphil199512430}}</ref>

Other terms for Thomistic dualism include hylomorphic dualism or [[Thomistic hylomorphism]] which are contrasted with substance dualism.<ref name="Feser 2005"/><ref>{{cite journal|author=Stango, Marco|year=2017|title=Understanding Hylomorphic Dualism|journal=Proceedings of the American Catholic Philosophical Association|url=https://www.pdcnet.org/acpaproc/content/acpaproc_2017_0091_0145_0158?file_type=pdf|volume=91|issue=|pages=145–158|doi=10.5840/acpaproc2019102295|url-access=subscription}}</ref><ref>{{cite journal|author=Skrzypek, Jeremy W.|year=2021|title=Not Just a Terminological Difference: Cartesian Substance Dualism vs Thomistic Hylomorphism|journal= Roczniki Filozoficzne|url=https://ojs.tnkul.pl/index.php/rf/article/view/15765|volume=69|issue=1|pages=103–117|doi=10.18290/rf21691-10|doi-access=free}}</ref> 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.<ref name="Feser 2005"/>

Thomistic scholars such as Paul Chutikorn and Edward Feser have written that Aquinas was not a substance dualist.<ref name="Chutikorn 2018">{{Cite web|author=Chutikorn, Paul|date=2018|title=A Thomistic Critique of Cartesian Dualism|url=https://thomistica.net/essays/2018/11/9/a-thomistic-critique-of-cartesian-dualism|website=Thomistica|language=en-GB|archive-date=September 25, 2024|archive-url=https://web.archive.org/web/20240925123920/https://thomistica.net/essays/2018/11/9/a-thomistic-critique-of-cartesian-dualism|url-status=live}}</ref><ref>{{Cite web|author=Feser, Edward|date=2020|title=Soul Proprietor|url=https://www.firstthings.com/article/2020/02/soul-proprietor|website=First Things|language=en-GB|archive-date=September 25, 2024|archive-url=https://web.archive.org/web/20240925182235/https://www.firstthings.com/article/2020/02/soul-proprietor|url-status=live}}</ref> 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.<ref name="Feser 2005"/> Paul Chutikorn has commented that "adopting Aquinas' view of substance will provide a solution to the problem by avoiding altogether the position that man is made up of dual substances. Rather, Aquinas shows us that we can acknowledge a duality within substance itself, while maintaining its inherent substantial unity".<ref name="Chutikorn 2018"/>

Aristotelian hylomorphic dualism also has many similarities with Thomistic dualism.<ref>{{Cite web|date=2023|title=Aristotelian Hylomorphic Dualism|url=https://thomistica.net/essays/https/thomisticanet/quaestiones-url/hylomorphic-dualism|website=Thomistica|language=en-GB|archive-date=September 27, 2024|archive-url=https://web.archive.org/web/20240927022733/https://thomistica.net/essays/https/thomisticanet/quaestiones-url/hylomorphic-dualism|url-status=live}}</ref> [[Michael Egnor]] is a notable advocate of Aristotelian dualism.<ref name="Stoke 2017">{{Cite web|author=Stoke, David|date=2017|title=Review of the 2017 Annual Meeting|url=https://christianscientific.org/review-of-the-2017-annual-meeting/|website=The Christian Scientific Society|language=en-GB|archive-date=September 22, 2024|archive-url=https://web.archive.org/web/20240922232435/https://christianscientific.org/review-of-the-2017-annual-meeting/|url-status=live}}</ref><ref name="Conference 2021">{{Cite web|date=2021|title=Science Beyond Materialism: Cosmology, Astrobiology, Consciousness|url=https://christianscholarsconference.org/panel/science-beyond-materialism-cosmology-astrobiology-consciousness/|website=Thomas H. Olbricht Christian Scholars Conference|language=en-GB|archive-date=September 22, 2024|archive-url=https://web.archive.org/web/20240922233432/https://christianscholarsconference.org/panel/science-beyond-materialism-cosmology-astrobiology-consciousness/|url-status=live}}</ref>

===Property dualism===
{{Main|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.<ref name="ist-socrates.berkeley.edu">[[John Searle|Searle, John]]. [1983] 2002. "[https://web.archive.org/web/20061210160023/http://ist-socrates.berkeley.edu/~jsearle/132/PropertydualismFNL.doc Why I Am Not a Property Dualist]." Archived from the [http://ist-socrates.berkeley.edu/~jsearle/132/PropertydualismFNL.doc original] on 10 December 2006.</ref>

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 (philosopher)|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 [[Causality|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.<ref name="ist-socrates.berkeley.edu" />

===Epiphenomenalism===
{{Main|Epiphenomenalism}}

Epiphenomenalism 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 [[Sensation (psychology)|sensations]], [[Volition (psychology)|volitions]], [[idea]]s, etc., such mental phenomena themselves cause nothing further: they are causal dead-ends. This can be contrasted to [[Interactionism (philosophy of mind)|interactionism]], on the other hand, in which mental causes can produce material effects, and vice versa.<ref name="Rob">[[Howard Robinson|Robinson, Howard]]. 2003. "Dualism." pp. 85–101 in ''The Blackwell Guide to Philosophy of Mind'', edited by S. Stich and T. Warfield. Oxford: Blackwell.</ref>

==={{Anchor|Predicate monism}}Predicate dualism<!--'Predicate dualism' redirects here-->===
'''Predicate dualism'''<!--boldface per WP:R#PLA--> is a view espoused by such non-reductive physicalists as [[Donald Davidson (philosopher)|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.<ref name="Davidson">Davidson, Donald. 1980. ''Essays on Actions and Events''. Oxford University Press. {{ISBN|0-19-924627-0}}.</ref><ref>Fodor, Jerry. 1968. ''Psychological Explanation''. Random House. {{ISBN|0-07-021412-3}}.</ref>

''Predicate dualism'' is most easily defined as the negation of ''predicate monism''. '''Predicate monism''' can be characterized as the view subscribed to by [[eliminative materialism|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).<ref name="Davidson" />

==Dualist views of mental causation==
[[File:DualismCausationViews3.svg|400px|thumb|Four varieties of dualist causal interaction. The arrows indicate the direction of causations. Mental and physical states are shown in red and blue, respectively.]]

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===
{{Main|Interactionism (philosophy of mind)}}

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]]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.<ref name="SEP" />

===Epiphenomenalism===
{{Main|Epiphenomenalism}}

[[Epiphenomenalism]] states that 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 ("''M1''") is caused by the firing of specific neurons in the brain ("''P1''"). When the arm and hand move to pick up the rock ("''P2''") this is not caused by the preceding mental event ''M1'', nor by ''M1'' and ''P1'' together, but only by ''P1''. The physical causes are in principle reducible to fundamental physics, and therefore mental causes are eliminated using this [[reductionist]] explanation. If P1 causes both ''M1'' and ''P2'', there is no [[overdetermination]] in the explanation for ''P2''.<ref name="SEP" />

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 [[Julien Offray de La Mettrie|La Mettrie]] (1745), and then by [[Pierre Jean George Cabanis|Cabanis]] (1802), and was further explicated by [[Shadworth Hodgson|Hodgson]] (1870) and [[T.H. Huxley|Huxley]] (1874).<ref>Gallagher, S. 2006. "Where's the action? Epiphenomenalism and the problem of free will". pp. 109–124 in ''Does Consciousness Cause Behavior?'', edited by S. Pockett, W. Banks, and S. Gallagher. Cambridge, MA: MIT Press.</ref> [[Frank Cameron Jackson|Jackson]] gave a [[#The subjective argument|subjective argument]] for epiphenomenalism, but later rejected it and embraced [[physicalism]].<ref name="Jackson 2003 251">{{cite journal|last=Jackson|first=Frank|title=Mind and Illusion|journal=Royal Institute of Philosophy Supplement|date=September 2003|volume=53|doi=10.1017/S1358246100008365|pages=251–271|s2cid=170304272}}</ref>

===Parallelism===
{{Main|Psychophysical 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 Leibniz|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.<ref name="Rob" />

===Occasionalism===
{{Main|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]].<ref name="Malebranche" />

===Kantianism===
{{Main|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.<ref>Aristotle. ''The Metaphysics'' 984b20, trans. by Hugh Lawson-Tancred. London, 2004.</ref>  He proposed that physical entities are static, while reason<ref>{{Cite book|title=The basic works of Aristotle|last=Aristotle|date=2001|publisher=Modern Library|others=McKeon, Richard (Richard Peter)|isbn=0375757996|location=New York|pages=696 (Metaphysics, Book 1, Chapter 3)|oclc=46634018}}</ref> 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.<ref>Sextus Empiricus, ''adv. Math.'' ix., ''ad Phys.'' i. 7</ref> 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.<ref name="Plat" />

In the ''Phaedo'', Plato makes it clear 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]], Plato likens the achievement of philosophical understanding to emerging into [[Metaphor of the Sun|the sunlight]] 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]] 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]] 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 and a posteriori|a priori]]'' considerations quite often. For example, Aristotle argues 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 causally efficient, they provide an immaterial complement for the formless mind.<ref name="Ari2">Aristotle. [c. mid 4th century BC] 1907. ''[[On the Soul|On the Soul (De anima)]]'', edited by [[Robert Drew Hicks|R. D. Hicks]]. Cambridge: Cambridge University Press; 1968. Books II-III, translated by D.W. Hamlyn, Clarendon Aristotle Series. Oxford: Oxford University Press.</ref>

===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]].<ref>Whittaker, 1901, ''The Neo-Platonists'', Cambridge: Cambridge University Press.</ref>

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.<ref name="auto">{{Cite web|url=https://www.newadvent.org/summa/1075.htm|archive-url=https://web.archive.org/web/20120119083516/http://www.newadvent.org/summa/1075.htm|title=Summa Theologiae: Man who is composed of a spiritual and a corporeal substance: and in the first place, concerning what belongs to the essence of the soul (Prima Pars, Q. 75)|url-status=dead|archive-date=19 January 2012|website=www.newadvent.org}}</ref> 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|Pontifical University of Saint Thomas Aquinas, ''Angelicum'']] during the academic year 1265–1266.<ref>Torrell, op. cit., 162</ref> By 1268 Aquinas had written at least the first book of the ''Sententia Libri De anima'', Aquinas' commentary on Aristotle's ''[[On the Soul|De anima]]'', the translation of which from the Greek was completed by Aquinas' Dominican associate at [[Viterbo]], [[William of Moerbeke]] in 1267.<ref>Torrell, 161 ff.</ref> 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.<ref>Aristotle, de Anima II. 1–2.</ref>

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,<ref name="auto"/> in contrast to the corruptibility of the vegetative and sensitive animation of plants and animals.<ref name="auto"/> His argument for the subsistence and incorruptibility of the intellectual soul takes its point of departure from the metaphysical principle that operation follows upon being (''agiture sequitur esse''), i.e., the activity of a thing reveals the mode of being and existence it depends upon. Since the intellectual soul exercises its own ''per se'' intellectual operations without employing material faculties, i.e. intellectual operations are immaterial, the intellect itself and the intellectual soul, must likewise be immaterial and so incorruptible. Even though the intellectual soul of man is able to subsist upon the death of the human being, Aquinas does not hold that the human person is able to remain integrated at death. The separated intellectual soul is neither a man nor a human person. The intellectual soul ''by itself'' is ''not'' a human person (i.e., an individual ''supposit'' of a rational nature).<ref>Summa theologiae, I. 29.1; 75.4ad2; Disputed Questions on the Soul I.</ref> 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.<ref>[[Thomas Aquinas|Aquinas, Thomas]] ''Summa Theologica''. trans. Fathers of the English Dominican Province, 2d, rev. ed., 22 vols., London: Burns, Oates & Washbourne; reprinted in 5 vols., Westminster, MD: Christian Classics, 1981.</ref>

The [[Catholic]] doctrine of the [[Universal resurrection|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<ref>{{cite web
 |title       = Apostles' Creed
 |work        = Catechism of the Catholic Church
 |url         = http://www.va/archive/catechism/p1s1c3a2.htm#credo
 |url-status  = live
 |archive-url  = https://web.archive.org/web/20070928055619/http://www.va/archive/catechism/p1s1c3a2.htm#credo
 |archive-date = 2007-09-28
}}</ref> 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.<ref>[[John Shelby Spong|Spong, John Selby]]. 1994. ''Resurrection: Myth or Reality''. New York: HarperCollins Publishing. {{ISBN|0-06-067546-2}}.</ref>

===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.<ref name="De" /> 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" ({{langx|la|[[res cogitans]]}}), and an immaterial [[Substance theory|substance]]. This "thing" was the essence of himself, that which doubts, believes, hopes, and thinks. The body, "the thing that exists" ({{langx|la|[[res extensa]]|label=none}}), regulates normal bodily functions (such as heart and liver). According to Descartes, animals only had a body and not a soul (which distinguishes humans from animals). 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.

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 [[Cerebral hemispheres|hemispheres]].<ref name="De" /> 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]] and [[Nicolas Malebranche]], proposed a different explanation: That all mind–body interactions required the direct intervention of God. According to these philosophers, the appropriate states of mind and body were only the ''occasions'' for such intervention, not real causes. These [[occasionalism|occasionalists]] 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.<ref name="Malebranche">[[Tad Schmaltz|Schmaltz, Tad]]. [2002] 2017. "[http://plato.stanford.edu/entries/malebranche/ Nicolas Malebranche]." ''The Stanford Encyclopedia of Philosophy'', edited by [[Edward N. Zalta|E. N. Zalta]].</ref>

===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 Cameron Jackson|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.<ref name="Oldhoff 2019">{{cite journal|author=Oldhoff, Martine C. L.|year=2019|title=Review of The Blackwell Companion to Substance Dualism|journal=Journal of Analytic Theology|url=https://jat-ojs-baylor.tdl.org/jat/index.php/jat/article/view/316/541|volume=7|issue=1|pages=753–758|doi=10.12978/jat.2019-7.1200-51141105|doi-access=free}}</ref><ref>{{cite journal|author=Prestes III, Flavio|year=2019|title=Review: The Blackwell Companion to Substance Dualism|journal=Andrews University Seminary Studies |url=https://digitalcommons.andrews.edu/auss/vol57/iss2/21/|volume=57|issue=2|pages=414–418}}</ref> Contributors include [[Charles Taliaferro]], Edward Feser, William Hasker, J. P. Moreland, Richard Swinburne, [[Lynne Rudder Baker]], John W. Cooper and Timothy O'Connor.<ref name="Oldhoff 2019"/>

==Arguments for dualism==
[[File:Descartes-reflex.JPG|thumb|right|Another one of Descartes' illustrations. The fire displaces the skin, which pulls a tiny thread, which opens a pore in the ventricle (F) allowing the "animal spirit" to flow through a hollow tube, which inflates the muscle of the leg, causing the foot to withdraw.]]

===The subjective argument===
An important fact is that minds perceive intra-mental states differently from sensory phenomena,<ref>{{cite journal|last=Prinz|first=Wolfgang|title=Why don't we perceive our brain states?|journal=European Journal of Cognitive Psychology|date=January 1992|volume=4|issue=1|doi=10.1080/09541449208406240 |pages=1–20}}<!--|access-date=19 November 2012--></ref> 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.<ref name="Nag">[[Thomas Nagel|Nagel, Thomas]]. 1986. ''[[The View from Nowhere]]''. New York: Oxford University Press.</ref> 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.<ref name="Hart" />

[[Thomas Nagel]] 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. However, others argue that ''qualia'' are consequent of the same neurological processes that engender the bat's mind, and will be fully understood as the [[neural correlates of consciousness|science]] develops.<ref>{{cite book|last=Dennett|first=Daniel C.|title=Consciousness Explained|year=1991|publisher=Little, Brown and Co|isbn=978-0-316-18065-8|url=https://archive.org/details/consciousnessexp00denn}}</ref>

[[Frank Cameron Jackson|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.<ref>Jackson, Frank. 1977. ''Perception: A Representative Theory''. Cambridge: Cambridge University Press.</ref>

However, Jackson later rejected his argument and embraced [[physicalism]].<ref>{{cite book|last=O'Hear|first=Anthony|title=Mind and Illusion, in "Minds and Persons"|year=2003|publisher=Cambridge University Press|page=251}}</ref> He notes that Mary obtains knowledge not of color, but of a new intramental state, ''seeing color''.<ref name="Jackson 2003 251" /> Also, he notes that Mary might say "wow," and as a mental state affecting the physical, this clashed with his former view of [[epiphenomenalism]]. [[David Kellogg Lewis|David Lewis]]' 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.<ref>Lewis, David. [1988] 1999. "What Experience Teaches." pp. 262–290 in ''Papers in Metaphysics and Epistemology'', Cambridge: Cambridge University Press.</ref> [[Daniel Dennett]] and others also provide [[Mary's room#Objections|arguments against this notion]].

===The zombie argument===
{{Main|Philosophical zombie}}
{{See also|Chinese room|Knowledge argument}}

The [[p-zombie|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.<ref>{{cite book |author=Chalmers, David |title=The Conscious Mind |publisher=Oxford University Press|year=1997 |isbn=978-0-19-511789-9}}</ref><ref>{{cite book |author=Chalmers, David |title=The Character of Consciousness|publisher=Oxford University Press |year=2010 |isbn=978-0-19-531110-5}}</ref>

Others such as Dennett have [[Philosophical zombie#Criticism|argued]] that the notion of a philosophical zombie is an incoherent,<ref>{{cite journal |author=Dennett, Daniel |title=The unimagined preposterousness of zombies |year=1995 |journal=Journal of Consciousness Studies|volume=2 |pages=322–326}}</ref> or unlikely,<ref>{{cite book |author=Dennett, Daniel |title=Consciousness Explained |publisher=Little, Brown and Co. |year=1991 |page=[https://archive.org/details/consciousnessexp00denn/page/95 95] |isbn=978-0-316-18065-8 |url=https://archive.org/details/consciousnessexp00denn/page/95 }}</ref> 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.<ref>{{cite journal |last1=Elitzur |first1=Avshalom |date=2009 |title=Consciousness makes a difference: A reluctant dualist's confession |url=https://philarchive.org/rec/ELICMA |journal=Irreducibly Conscious. Selected Papers on Consciousness |volume= |issue= |pages= |doi= |access-date=24 January 2025}}</ref>

===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.<ref name="Rob" /> Psychology is one such science; it completely depends on and presupposes the existence of the mind.

Physics is the general analysis of [[nature]], conducted to understand how the [[universe]] behaves. On the other hand, the study of [[meteorology|meteorological]] weather patterns or [[Behavioral science|human behavior]] is only of interest to humans themselves. 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 to perceive the physical world as psychological, the mind must have a perspective on the physical. This, in turn, presupposes the existence of mind.<ref name="Rob" />

However, [[cognitive science]]<ref>{{cite book|last=Pylyshyn|first=Zenon W.|title=Computation and Cognition|year=1986|publisher=MIT Press|isbn=978-0262660587|page=259}}</ref> and psychology<ref>{{cite journal|last=Schwarz|first=Jeffrey M.|author2=Stapp, Henry P.|author3=Beauregard, Mario|date=June 2005|title=Quantum Physics in Neuroscience and Psychology: A Neurophysical Model of Mind-Brain Interaction|journal=Philosophical Transactions: Biological Sciences|volume=360|issue=1458|pages=1309–1327|doi=10.1098/rstb.2004.1598|jstor=30041344|pmc=1569494|pmid=16147524}}<!--|access-date=20 November 2012--></ref> 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;<ref name=chemistry>{{cite book|last=Brown|title=Chemistry|year=2003|publisher=Prentice Hall|location=NJ|isbn=978-0-13-066997-1|pages=2–3}}</ref> while fields such as [[chemistry]],<ref>{{cite journal|last=Various|date=December 1994|title=Accurate First Principles Calculation of Molecular Charge Distributions and Solvation Energies from Ab Initio Quantum Mechanics and Continuum Dielectric Theory|journal=J. Am. Chem. Soc.|volume=116|issue=26|pages=11875–11882|doi=10.1021/ja00105a030|bibcode=1994JAChS.11611875T |s2cid=10518482}}<!--|access-date=20 November 2012--></ref> [[biology]],<ref>{{cite journal|last=Ma|first=Buyong|author2=Nussinov, Ruth|title=From computational quantum chemistry to computational biology: experiments and computations are (full) partners|journal=Phys. Biol.|date=November 2004|volume=1|issue=4|pages=23–6|doi=10.1088/1478-3967/1/4/P01 |pmid=16204832|bibcode=2004PhBio...1P..23M|s2cid=24333007 |url=https://zenodo.org/record/1235734}}<!--|access-date=20 November 2012--></ref> or geology<ref>{{cite journal|last=Various|date=April 2010|title=Quantum Monte Carlo computations of phase stability, equations of state, and elasticity of high-pressure silica|journal=PNAS|volume=107|issue=21|pages=9519–9524|arxiv=1001.2066|bibcode=2010PNAS..107.9519D|doi=10.1073/pnas.0912130107|pmc=2906913|pmid=20457932|doi-access=free}}<!--|access-date=20 November 2012--></ref> could be verbosely expressed in terms of [[quantum field theory]], it is convenient to use levels of abstraction like [[molecules]], [[Cell (biology)|cells]], or the [[Mantle (geology)|mantle]]. It is often difficult to decompose these levels without heavy analysis<ref>{{cite journal|last=Pyykko|first=Pekka|date=21 July 2012|title=The Physics behind Chemistry and the Periodic Table|journal=Chem. Rev.|volume=112|issue=1|pages=371–384|doi=10.1021/cr200042e|pmid=21774555|s2cid=46487006}}<!--|access-date=10 November 2012--></ref> and computation.<ref>{{cite journal|last=Pyykko|first=Pekka|title=A suggested periodic table up to Z ≤ 172, based on Dirac–Fock calculations on atoms and ions|journal=Physical Chemistry Chemical Physics|date=22 Oct 2010|volume=13|issue=1|pages=161–168|doi=10.1039/C0CP01575J|pmid=20967377|bibcode=2011PCCP...13..161P|s2cid=31590563}}</ref> Sober has also advanced philosophical arguments against the notion of irreducibility.<ref>{{cite journal|last=Sober|first=Elliott|date=December 1999|title=The Multiple Realizability Argument against Reductionism|journal=Philosophy of Science|volume=66|issue=4|pages=542–564|doi=10.1086/392754|jstor=188749|s2cid=54883322}}<!--|access-date=20 November 2012--></ref>

===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.<ref name="MG">Madell, G. 1981. ''The Identity of the Self''. Edinburgh: Edinburgh University Press.</ref> 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:<ref name="MG" />

: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?<ref>Shoemaker, S., and [[Richard Swinburne]]. 1984. ''Personal Identity''. Oxford: Blackwell.</ref> 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.<ref name="SR">[[Richard Swinburne|Swinburne, Richard]]. 1979. ''The Existence of God''. Oxford: Oxford University Press.</ref>

[[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.<ref>{{cite web |url=https://philpapers.org/rec/LISTFA |title=The first-personal argument against physicalism |last=List |first=Christian |date=2023 |publisher= |access-date=3 September 2024 }}</ref>

===Argument from reason===
{{Main|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 (book)|Miracles]]''; Lewis called the argument "The Cardinal Difficulty of Naturalism", which was the title of chapter three of ''Miracles''.<ref name="Reppert">[[Victor Reppert|Reppert, Victor]]. 2003. ''C.S. Lewis's Dangerous Idea''. Downers Grove, IL: InterVarsity Press. {{ISBN|0-8308-2732-3}}</ref>

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.<ref name=Reppert />

Through this logic, the statement "I have reason to believe naturalism is valid" is inconsistent in the same manner as "I never tell the truth."<ref>{{Cite web|url=https://infidels.org/library/modern/darek_barefoot/dangerous.html|archive-url=https://web.archive.org/web/20081220020836/http://www.infidels.org/library/modern/darek_barefoot/dangerous.html|url-status=dead|title=A Response to Richard Carrier's Review of C.S. Lewis's Dangerous Idea|archive-date=20 December 2008|website=infidels.org}}</ref> 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:<ref>{{Cite web|url=https://philosophy.uncc.edu/|archive-url=https://web.archive.org/web/20081220015347/http://www.philosophy.uncc.edu/mleldrid/Intro/csl3.html|url-status=dead|title=Philosophy Homepage &#124; Department of Philosophy &#124; UNC Charlotte|archive-date=20 December 2008|website=philosophy.uncc.edu}}</ref>

{{Blockquote|text=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.|sign=J. B. S. Haldane|source=p. 209|title=''Possible Worlds''}}

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

{{Blockquote|text=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.|sign=C. S. Lewis|source=p. 139|title=''[[The Weight of Glory and Other Addresses]]''}}

But Lewis later agreed with [[Elizabeth Anscombe]]'s response to his ''Miracles'' argument.<ref>{{cite book|last=Sayer|first=George|title=Jack: A Life of C. S. Lewis|year=2005|publisher=Crossway|isbn=978-1581347395|url-access=registration|url=https://archive.org/details/jacklifeofcslewi0000saye}}</ref> She showed that an argument could be valid and ground-consequent even if its propositions were generated via [[causality (physics)|physical cause and effect]] by non-rational factors.<ref>''The Socratic Digest'', No. 4 (1948)</ref> Similar to Anscombe, [[Richard Carrier]] and John Beversluis have written extensive objections to the [[argument from reason]] on the untenability of its first postulate.<ref>{{cite book|last=Beversluis|first=John|title=C.S. Lewis and the Search for Rational Religion (Revised and Updated)|year=2007|publisher=Prometheus Books|isbn=978-1591025313}}</ref>

===Cartesian arguments===
{{Main|Meditations on the First Philosophy}}

Descartes puts forward two main arguments for dualism in ''[[Meditations on the First Philosophy|Meditations]]'': firstly, the "modal argument," or the "clear and distinct perception argument," and secondly the "indivisibility" or "divisibility" argument.
{| class="wikitable"
|+Summary of the 'modal argument'<ref>{{Cite book|chapter-url=https://plato.stanford.edu/entries/dualism/#ModArg|title = The Stanford Encyclopedia of Philosophy|chapter = Dualism|year = 2020|publisher = Metaphysics Research Lab, Stanford University}}</ref>
| colspan="4" |It is imaginable that one's mind might exist without one's body.
|-
| colspan="4" |''therefore''
|-
| colspan="4" |It is conceivable that one's mind might exist without one's body.
|-
| colspan="4" |''therefore''
|-
| colspan="4" |It is possible one's mind might exist without one's body.
|-
| colspan="4" |''therefore''
|-
| colspan="4" |One's mind is a different entity from one's body.
|}
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.<ref>[[Howard Robinson|Robinson, Howard]]. [2003] 2016. "[https://plato.stanford.edu/entries/dualism/#ModArg Dualism § The Modal Argument]." ''[[Stanford Encyclopedia of Philosophy]]''.</ref> [[Alvin Plantinga]],<ref>[[Robert Lawrence Kuhn|Kuhn, Robert Lawrence]], host. 2009. "[https://www.youtube.com/watch?v=WOTn_wRwDE0 Is the Person All Material?]" Ep. 43 in ''[[Closer to Truth|Closer to the Truth]]'' (television series). via YouTube.</ref> [[J. P. Moreland]],<ref>Everist, Randy. 30 December 2015. "[https://www.randyeverist.com/2015/12/the-modal-argument-for-substance.html The Modal Argument for Substance Dualism: A Spirited Defense, Part 1]." ''Possible Worlds''. Accessed 31 July 2020.</ref> and [[Edward Feser]]<ref>Feser, Edward. 13 April 2009. "[http://edwardfeser.blogspot.com/2009/04/descartes-clear-and-distinct-perception.html Descartes' "clear and distinct perception" argument]." {{Blogspot|edwardfeser|Edward Feser}}.</ref> 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:<ref>Calef, Scott. n.d. "[https://www.iep.utm.edu/dualism/#SH3a Dualism and Mind § The Argument From Indivisibility]." ''[[Internet Encyclopedia of Philosophy]]''.</ref><blockquote>[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...</blockquote>The argument relies upon [[Leibniz]]' [[identity of indiscernibles|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 [[Monad (philosophy)|monads]].<ref>[[Edward Feser|Feser, Edward]]. 27 February 2017. "[http://edwardfeser.blogspot.com/2015/02/descartes-indivisibility-argument.html Descartes' "indivisibility" argument]." {{Blogspot|edwardfeser|Edward Feser}}.</ref>

==Arguments against dualism==

===Arguments from causal interaction===
[[File:Dualism-vs-Monism.png|320px|thumb|right|Cartesian dualism compared to three forms of monism]]

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''.<ref>{{cite encyclopedia|title=c. Problems of Interaction|url=http://www.iep.utm.edu/dualism/#SH7c|encyclopedia=Internet Encyclopedia of Philosophy|access-date=15 November 2012|url-status=live|archive-url=https://web.archive.org/web/20121028131436/http://www.iep.utm.edu/dualism/#SH7c|archive-date=28 October 2012}}</ref>

====Replies====
[[Alfred North Whitehead]], and later [[David Ray Griffin]], framed a new ontology (''[[process philosophy]]'') seeking precisely to avoid the pitfalls of ontological dualism.<ref>[[Michel Weber|Weber, Michel]], and Anderson Weekes, eds. 2009. ''[https://www.academia.edu/279961/Process_Approaches_to_Consciousness_in_Psychology_Neuroscience_and_Philosophy_of_Mind Process Approaches to Consciousness in Psychology, Neuroscience, and Philosophy of Mind]'', Whitehead Psychology Nexus Studies II. Albany, NY: State University of New York Press. {{webarchive|url=https://web.archive.org/web/20150408022540/http://www.academia.edu/279961/Process_Approaches_to_Consciousness_in_Psychology_Neuroscience_and_Philosophy_of_Mind|date=2015-04-08}}</ref>

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 (book)|Miracles]]'',<ref>{{cite book
 |author= Lewis, C.S
 |title= Miracles
 |year= 1947
 |publisher= HarperCollins
 |isbn= 978-0-688-17369-2
 |url= https://archive.org/details/giftofmiraclesma00mill
 }}</ref> [[quantum mechanics]] (and physical [[Quantum indeterminacy|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.<ref name="SEPQD">{{cite encyclopedia|title=Causal Determinism of Quantum Mechanics|url=http://plato.stanford.edu/entries/determinism-causal/#QuaMec|encyclopedia=Stanford Encyclopedia of Philosophy|access-date=16 November 2012}}</ref>

===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]].<ref>Wilson, D. L. 1999. "Mind-brain interaction and the violation of physical laws." pp. 185–200 in ''The Volitional Brain'', edited by B. Libet, A. Freeman, and K. Sutherland. Thorverton, UK: Imprint Academic.</ref><ref>Mohrhoff, U. 1999. "The physics of interaction." pp. 165–184 in ''The Volitional Brain'', edited by B. Libet, A. Freeman, and K. Sutherland. Thorverton, UK: Imprint Academic.</ref><ref>{{cite journal | last1 = Jaswal | first1 = L | year = 2005 | title = Isolating disparate challenges to Hodgson's account of free will | journal = Journal of Consciousness Studies | volume = 12 | issue = 1 |pages = 43–46}}</ref><ref>{{cite journal | last1 = Clark | first1 = T. W. | year = 2005a | title = Hodgson's black box | journal = Journal of Consciousness Studies | volume = 12 | issue = 1 |pages = 38–59}}</ref>

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.<ref>Baker, Gordon and Morris, Katherine J. (1996) ''Descartes' Dualism'', London: Routledge.</ref> Such interactions would violate the fundamental [[physical law|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]].<ref>[[William Lycan|Lycan, William]]. 1996. "Philosophy of Mind." In ''[[The Blackwell Companion to Philosophy]]'', edited by N. Bunnin and E. P. Tsui-James. Oxford: Blackwell Publishers.</ref> 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]]''<ref name="SEP" /> and the ''[[New Catholic Encyclopedia]]''<ref name="CathEn">Maher, Michael (1909) "The Law of Conservation of Energy", ''Catholic Encyclopedia'', vol. 5, pp. 422 ff, {{cite web |url=http://www.newadvent.org/cathen/05422a.htm |title=Catholic Encyclopedia: The Law of Conservation of Energy |access-date=2007-05-20 |url-status=live |archive-url=https://web.archive.org/web/20070701235022/http://www.newadvent.org/cathen/05422a.htm |archive-date=2007-07-01}}.</ref> 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.<ref>{{cite book|last=Murphy|first=Nancy|title=Downward Causation and the Neurobiology of Free Will|year=2009|publisher=Springer|isbn=978-3642032042}}</ref> [[Robin Collins]] responds<ref>{{cite journal | last1 = Collins | first1 = Robin | authorlink = Robin Collins | year = 2008 | title = Modern Physics and the Energy Conservation Objection to Mind-Body Dualism | url = | journal = The American Philosophical Quarterly | volume = 45 | issue = 1| pages = 31–42 }}</ref> 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.<ref>{{cite web |url=http://www.newdualism.org/papers/R.Collins/EC-PEC.htm |title=Modern Physics and the Energy Conservation Objection to Mind-Body Dualism, by Robin Collins |access-date=2017-07-01 |url-status=live |archive-url=https://web.archive.org/web/20170625152408/http://www.newdualism.org/papers/R.Collins/EC-PEC.htm |archive-date=2017-06-25}}</ref> 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 [[overdetermination|overdetermined]], and can be explained by either physical or mental causes alone.<ref>{{cite journal|last=Mills|first=E.|title=Interactionism and Overdetermination|journal=American Philosophical Quarterly|year=1996|volume=33|pages=105–117}}</ref> An overdetermined event is fully accounted for by multiple causes at once.<ref>{{cite book|last=Althusser|first=Louis|title="Contradiction and Overdetermination," in For Marx|year=1985|publisher=Verso |isbn=978-0-902308-79-4}}</ref> 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.<ref>{{cite book|last=Churchland|first=Paul|title=Matter and Consciousness, Revised Edition|year=1984|publisher=MIT Press|isbn=978-0262530743}}</ref>

Howard Robinson suggests that the interaction may involve [[dark energy]], [[dark matter]] or some other currently unknown scientific process.<ref name="Rob" />

Another reply is that the interaction taking place in the human body may not be described by "billiard ball" [[classical mechanics]]. If a nondeterministic interpretation of [[quantum mechanics]] is correct then microscopic events are [[indeterminism|indeterminate]], where the degree of [[determinism]] increases with the scale of the system. Philosophers [[Karl Popper]] and [[John Carew Eccles|John Eccles]] and physicist [[Henry Stapp]] have theorized that such indeterminacy may apply at the macroscopic scale.<ref>[[Karl Popper|Popper, Karl R.]], and [[John Eccles (neurophysiologist)|John C. Eccles]]. 1977. ''The Self and Its Brain''. Berlin: Springer.</ref> However, [[Max Tegmark]] has argued that classical and quantum calculations show that [[quantum decoherence]] effects do not play a role in brain activity.<ref>{{cite journal|last=Tegmark|first=Max|title=Importance of quantum decoherence in brain processes|journal=Phys. Rev. E|date=April 2000|volume=61|issue=4|pages=4194–4206|doi=10.1103/PhysRevE.61.4194|pmid=11088215|arxiv=quant-ph/9907009|bibcode=2000PhRvE..61.4194T|s2cid=17140058}}</ref>

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, [[Thomism|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.<ref>{{cite web |url=http://edwardfeser.blogspot.com/2016/09/mind-body-interaction-whats-problem.html |title=Edward Feser: Mind-body interaction: What's the problem? |access-date=2017-04-24 |url-status=live |archive-url=https://web.archive.org/web/20170425032034/http://edwardfeser.blogspot.com/2016/09/mind-body-interaction-whats-problem.html |archive-date=2017-04-25 |date=2016-09-17}}</ref>

===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.<ref>[[Paul Churchland|Churchland, Paul]]. 1988. ''Matter and Consciousness'' (rev. ed.). Cambridge, MA: MIT Press.</ref>

[[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,<ref>(September 2008). "Phineas Gage – Unravelling the myth". The Psychologist. 21 (9): 828–31.</ref> and that he made a reasonable social and mental recovery.<ref>{{cite journal | last1 = Lena | first1 = M. L. | year = 2010 | title = Rehabilitating Phineas Gage | url = | journal = Neuropsychological Rehabilitation | volume = 20 | issue = 5| pages = 641–58 | doi = 10.1080/09602011003760527 | pmid = 20480430 }}</ref> The changes in question have almost always been distorted and exaggerated by scientific and popular literature, often relying on hearsay.<ref>Macmillan, Malcolm B. (2014). "Phineas Gage". Encyclopedia of the Neurological Sciences. Academic Press. p. 383.</ref><ref>Kotowicz, Z. (2007). "The strange case of Phineas Gage". History of the Human Sciences. 20 (1): 115–31.</ref><ref>Grafman, J. (2002). "The Structured Event Complex and the Human Prefrontal Cortex". In Stuss, D. T.; Knight, R. T. (eds.). Principles of Frontal Lobe Function. pp. 292–310.</ref> Similar examples abound; neuroscientist [[David Eagleman]] describes the case of another individual who exhibited escalating [[pedophile|pedophilic]] tendencies at two different times, and in each case was found to have tumors growing in a particular part of his brain.<ref>Choi, Charles. 21 October 2002. "[https://www.newscientist.com/article/dn2943-brain-tumour-causes-uncontrollable-paedophilia.htmlNewScientist.com, Brain tumour causes uncontrollable paedophilia]." ''[[New Scientist]]''. {{webarchive|url=https://web.archive.org/web/20150412195711/http://www.newscientist.com/article/dn2943-brain-tumour-causes-uncontrollable-paedophilia.htmlNewScientist.com,|date=2015-04-12}}.</ref><ref>[[Nigel Warburton|Warburton, Nigel]], and [[David Edmonds (philosopher)|David Edmonds]], hosts. 22 May 2011. "[https://philosophybites.com/2011/05/david-eagleman-on-morality-and-the-brain.html David Eagleman on Morality and the Brain]." ''[[Philosophy Bites]]'' (podcast).</ref>

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,<ref>{{cite journal|pmid=11190987 | volume=25 | issue=1 | title=Verbal and visual memory improve after choline supplementation in long-term total parenteral nutrition: a pilot study | year=2001 | journal=JPEN J Parenter Enteral Nutr | pages=30–35 |vauthors=Buchman AL, Sohel M, Brown M |doi=10.1177/014860710102500130|display-authors=etal}}</ref> but also from research on [[neurostimulation]] (direct electrical stimulation of the brain, including [[transcranial magnetic stimulation]]).<ref>''Alterations of sociomoral judgement and glucose use in the frontomedial cortex induced by electrical stimulation of the subthalamic nucleus (STN) in Parkinsonian patients (2004):'' {{cite journal |journal=Genman Medical Science |url=http://www.egms.de/de/meetings/dgnc2004/04dgnc0207.shtml |title=Alterations of sociomoral judgement and glucose utilization in the frontomedial cortex induced by electrical stimulation of the subthalamic nucleus (STN) in Parkinsonian patients |pages=DocDI.06.06 |access-date=2008-09-08 |url-status=live |archive-url=https://web.archive.org/web/20040903084719/http://www.egms.de/de/meetings/dgnc2004/04dgnc0207.shtml |archive-date=2004-09-03 |date=2004-04-23}}</ref>

====Replies====

[[Property dualism]] and [[William Hasker]]'s "emergent dualism"<ref>[http://plato.stanford.edu/entries/properties-emergent/ Stanford Encyclopedia of Philosophy, "Emergent Properties"]. Excerpt: "William Hasker (1999) goes one step further in arguing for the existence of the mind conceived as a non-composite substance which 'emerges' from the brain at a certain point in its development. He dubs his position 'emergent dualism,' and claims for it all the philosophical advantages of traditional, Cartesian substance dualism while being able to overcome a central difficulty, viz., explaining how individual brains and mental substances come to be linked in a persistent, 'monogamous' relationship. Here, Hasker, is using the term to express a view structurally like one (vitalism) that the British emergentists were anxious to disavow, thus proving that the term is capable of evoking all manner of ideas for metaphysicians."</ref> 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 {{as written|i|t's}} origin of action." Thus, if the body is dysfunctional, the intellect will not actualize as it intends to.<ref>{{Cite web|url=https://www.newadvent.org/summa/1075.htm|title=Summa Theologiae: Man who is composed of a spiritual and a corporeal substance: and in the first place, concerning what belongs to the essence of the soul}} Article 2, Reply to Objection 3.</ref> According to the philosopher [[C. Stephen Evans|Stephen Evans]]:

{{blockquote|We did not need [[neurophysiology]] to come to know that a person whose head is bashed in with a club quickly loses his or her ability to think or have any conscious processes. Why should we not think of neurophysiological findings as giving us detailed, precise knowledge of something that human beings have always known, or at least could have known, which is that the mind (at least in this mortal life) requires and depends on a functioning brain? We now know a lot more than we used to know about precisely ''how'' the mind depends on the body. However, ''that'' the mind depends on the body, at least prior to death, is surely not something discovered in the 20th century".<ref>{{cite journal | last1 = Evans | first1 = C. Stephen | authorlink = C. Stephen Evans | year = 2005 | title = Separable Souls: Dualism, Selfhood, and the Possibility of Life After Death | url = | journal = Christian Scholars Review | volume = 34 | issue = | pages = 333–34 }}</ref>}}

===Argument from neuroscience <span class="anchor" id="Argument from brain scans' ability to discern mental states"></span> ===
{{see also|Neurophilosophy|Neuroscience of free will|Thought identification}}

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.<ref>{{cite journal |title=Unconscious determinants of free decisions in the human brain |journal=Nature Neuroscience |volume=11 |issue=5 |pages=543–545 |doi=10.1038/nn.2112 |pmid=18408715 |date=May 2008 |last1=Haynes |first1=John-Dylan |last2=Heinze |first2=Hans-Jochen |last3=Brass |first3=Marcel |last4=Soon |first4=Chun Siong|s2cid=2652613 }}</ref> Subjective experiences and covert attitudes can be detected,<ref name=readstates>{{cite journal|last=Haynes|first=John-Dylan|author2=Rees, Geraint|title=Decoding mental states from brain activity in humans|journal=Nature Reviews Neuroscience|date=July 2006|volume=7|pages=523–534|doi=10.1038/nrn1931|issue=7|pmid=16791142|s2cid=16025026}}</ref> as can [[mental imagery]].<ref>{{cite web|url=http://despolab.berkeley.edu/files/publications/pdf/imagerot.pdf |title=Archived copy |access-date=2011-06-29 |url-status=dead |archive-url=https://web.archive.org/web/20110921093335/http://despolab.berkeley.edu/files/publications/pdf/imagerot.pdf |archive-date=2011-09-21}}</ref> This is cited as [[empirical evidence]] that [[cognitive processes]] have a physical basis in the brain.<ref name=Cognition>{{cite journal|last=Dehaene|first=Stanislas|author2=Naccache, Lionel|title=Towards a cognitive neuroscience of consciousness: basic evidence and a workspace framework|journal=Cognition|date=April 2001|volume=79|issue=1–2|pages=1–37|doi=10.1016/S0010-0277(00)00123-2 |pmid=11164022|s2cid=1762431}}<!--|access-date=21 February 2013--></ref><ref name="Dehaene">{{cite book|last=Dehaene|first=Stanislas|publisher=MIT|title=The Cognitive Neuroscience of Consciousness|year=2002|page=4|isbn=978-0262541312}}</ref>

====Replies====
[[Thomism|Thomist]] philosopher [[Edward Feser]] criticises the use of neuroscience to support a [[naturalism (philosophy)|naturalist]] account of the mind, drawing from philosopher [[Tyler Burge]]<ref>{{Cite web|url=https://archive.nytimes.com/opinionator.blogs.nytimes.com/2010/12/19/a-real-science-of-mind/|title= Tyler Burge, A Real Science of Mind - The New York Times|date= 19 December 2010}}</ref> 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.<ref>{{Cite web|url=https://edwardfeser.blogspot.com/2011/01/against-neurobabble.html|title= Edward Feser: Against "Neurobabble"|date= 20 January 2011}}</ref>

===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.

This argument was criticized by [[Peter Glassen]] in a debate with [[J. J. C. Smart]] in the pages of ''[[Philosophy (journal)|Philosophy]]'' in the late 1970s and early 1980s.<ref>{{cite journal | last1 = Glassen | first1 = Peter | year = 1976 | title = J. J. C. Smart, Materialism and Occam's Razor | journal = Philosophy | volume = 51 | issue = 197| pages = 349–352 | doi=10.1017/s0031819100019392| s2cid = 170163667 }}</ref><ref>{{cite journal | last1 = Smart | first1 = J. J. C. | year = 1978 | title = Is Occam's Razor a Physical Thing? | journal = Philosophy | volume = 53 | issue = 205| pages = 382–385 | doi=10.1017/s0031819100022439| s2cid = 170593277 }}</ref><ref>{{cite journal | last1 = Glassen | first1 = Peter | year = 1983 | title = Smart, Materialism and Believing | journal = Philosophy | volume = 58 | issue = 223| pages = 95–101 | doi=10.1017/s0031819100056291| s2cid = 170472361 }}</ref> 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).<ref name=Stanford>[http://plato.stanford.edu/entries/simplicity/ Plato Stanford Encyclopedia of Philosophy: Simplicity]. Excerpt: "Perhaps scientists apply an unrestricted version of Occam's Razor to that portion of reality in which they are interested, namely the concrete, causal, spatiotemporal world. Or perhaps scientists apply a 'concretized' version of Occam's Razor unrestrictedly. Which is the case? The answer determines which general philosophical principle we end up with: ought we to avoid the multiplication of objects of whatever kind, or merely the multiplication of concrete objects? The distinction here is crucial for a number of central philosophical debates. Unrestricted Occam's Razor favors monism over dualism, and nominalism over platonism. By contrast, 'concretized' Occam's Razor has no bearing on these debates, since the extra entities in each case are not concrete".</ref>

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.<ref name="Mousavirad 2023"/>

==See also==
* [[Explanatory gap]]
* [[Mentalism (psychology)]]
* [[Nonduality (spirituality)|Nondualism]]
* [[Hard problem of consciousness]]
* [[Bipartite (theology)]]
* ''[[The Concept of Mind]]'' by [[Gilbert Ryle]]
* [[Trialism]]
* [[Advaita vedanta]]
* [[Vertiginous question]]

==References==
{{Reflist|30em}}

==Further reading==
* Amoroso, Richard L. 2010. ''Complementarity of Mind and Body: Realizing the Dream of Descartes, Einstein and Eccles''. {{ISBN|978-1-61668-203-3}}. History making volume with first comprehensive model of dualism-interactionism, that is also empirically testable.
* {{cite journal | last1 = Bracken | first1 = Patrick | last2 = Thomas | first2 = Philip | year = 2002 | title = Time to move beyond the mind–body split | url = | journal = [[British Medical Journal]] | volume = 325 | issue = 7378| pages = 1433–1434 | doi = 10.1136/bmj.325.7378.1433 | pmid = 12493651 | pmc = 1124895 }} A controversial perspective on the use and possible overuse of the Mind–Body split and its application in medical practice.
* [[Antonio Damasio|Damasio, Antonio]]. 1994. ''[[Descartes' Error]]''.
* Sinclair, Alistair J. 2015. ''The Promise of Dualism''. Almostic Publications. {{ASIN|0957404433}}. Introducing dualism as being interactive and distinct from the substance dualism of Descartes.
* Spenard, Michael. 2011. {{usurped|1=[https://web.archive.org/web/20110928230010/http://www.memeoid.net/books/Spenard/Dueling_with_Dualism-Spenard.pdf ''Dueling with Dualism: the forlorn quest for the immaterial soul'']}}. {{ISBN|978-0-578-08288-2}}. An historical account of mind body dualism and a comprehensive conceptual and an empirical critique of the position.
* {{cite journal | last1 = Sperry | first1 = R. W. | year = 1980 | title = Mind-brain interaction: Mentalism, yes; dualism, no. | url = | journal = [[Neuroscience (journal)|Neuroscience]] | volume = 5 | issue = 2| pages = 195–206 | doi = 10.1016/0306-4522(80)90098-6 | pmid = 7374938 }}

==External links==
{{wikiquote}}
* {{Wikibooks inline|Consciousness Studies}}
* "[https://web.archive.org/web/20110709120241/http://philosophy.uwaterloo.ca/MindDict/dualism.html Dualism]." ''Dictionary of Philosophy of Mind''
* "[http://plato.stanford.edu/entries/dualism/ Dualism]." the ''[[Stanford Encyclopedia of Philosophy]]''
* "[http://plato.stanford.edu/entries/zombies/ Zombies]." ''Stanford Encyclopedia of Philosophy''
* {{cite IEP |url-id=dualism |title=Dualism and Mind}}
* {{PhilPapers|category|dualism|Dualism}}
* {{InPho|taxonomy|2199|Dualism}}
* [https://serendipstudio.org/Mind/Table.html Mind and body, Rene Descartes to William James]
* [https://archive.today/20121212013222/http://www.u.arizona.edu/~chalmers/online1.html%23materialism Online Papers on Materialism and Dualism]
* [https://theessaytopic.org/dualism-arguments-pros-amp-cons Dualism Arguments: Pros & Cons] {{Webarchive|url=https://web.archive.org/web/20181002141837/https://theessaytopic.org/dualism-arguments-pros-amp-cons |date=2 October 2018 }}

{{Metaphysics}}
{{Mind–body dualism}}
{{Philosophy of mind}}
{{Consciousness}}
{{Catholic philosophy footer}}

{{DEFAULTSORT:Mind-body dualism}}
[[Category:Dualism (philosophy of mind)| ]]
[[Category:Arguments in philosophy of mind]]
[[Category:Baruch Spinoza]]
[[Category:Cartesianism]]
[[Category:Concepts in epistemology]]
[[Category:Concepts in metaphysics]]
[[Category:Concepts in the philosophy of mind]]
[[Category:Consciousness]]
[[Category:Metaphysics of mind]]
[[Category:Ontology]]
[[Category:René Descartes]]
[[Category:Theory of mind]]