A wide variety of solutions have been proposed. Most of them can be placed into categories known as Dualism and Monism. Dualist solutions maintain a rigid distinction between the realm of mind and the realm of matter. Monist solutions maintain that there is really only one realm of being, of which mind and matter are both aspects. Each of these categories itself contains numerous variants. The two main types of dualism are substance dualism (which holds that the mind is formed of a distinct type of substance not governed by the laws of physics) and property dualism (which holds that the laws of physics are universally valid but cannot be used to explain the mind). The three main types of monism are physicalism (which holds that the mind consists of matter organized in a particular way), idealism (which holds that only thought truly exists and matter is merely an illusion), and neutral monism (which holds that both mind and matter are aspects of a distinct essence that is itself identical to neither of them). A third category of solution, not very popular among western philosophers but widely held in eastern religions such as Buddhism, is nihilism, the belief that both mind and matter are illusions.
A dualist view of reality may lead one to consider the corporeal as little valued and trivial. The rejection of the mind–body dichotomy is found in French Structuralism, and is a position that generally characterized post-war French philosophy. The absence of an empirically identifiable meeting point between the non-physical mind and its physical extension has proven problematic to dualism and many modern philosophers of mind maintain that the mind is not something separate from the body. These approaches have been particularly influential in the sciences, particularly in the fields of sociobiology, computer science, evolutionary psychology, and the neurosciences.
 Mind-body interaction and mental causationPhilosophers David Robb and John Heil introduce mental causation in terms of the mind-body problem of interaction:
Contemporary neurophilosopher, Georg Northoff suggests that mental causation is compatible with classical formal and final causality:Mind-body interaction has a central place in our pretheoretic conception of agency... Indeed, mental causation often figures explicitly in formulations of the mind-body problem... Some philosophers (e.g., Davidson 1963; Mele 1992) insist that the very notion of psychological explanation turns on the intelligibility of mental causation. If your mind and its states, such as your beliefs and desires, were causally isolated from your bodily behavior, then what goes on in your mind could not explain what you do. [For contrary views, see Ginet 1990; Sehon 2005...] If psychological explanation goes, so do the closely related notions of agency and moral responsibility (cf. Horgan 2007)... Clearly, a good deal rides on a satisfactory solution to the problem of mental causation [and] there is more than one way in which puzzles about the mind's “causal relevance” to behavior (and to the physical world more generally) can arise.[René Descartes] set the agenda for subsequent discussions of the mind-body relation. According to Descartes, minds and bodies are distinct kinds of substance. Bodies, he held, are spatially extended substances, incapable of feeling or thought; minds, in contrast, are unextended, thinking, feeling substances... If minds and bodies are radically different kinds of substance, however, it is not easy to see how they could causally interact... Princess Elizabeth of Bohemia puts it forcefully to him in a 1643 letter...
how the human soul can determine the movement of the animal spirits in the body so as to perform voluntary acts—being as it is merely a conscious substance. For the determination of movement seems always to come about from the moving body's being propelled—to depend on the kind of impulse it gets from what sets it in motion, or again, on the nature and shape of this latter thing's surface. Now the first two conditions involve contact, and the third involves that the impelling thing has extension; but you utterly exclude extension from your notion of soul, and contact seems to me incompatible with a thing's being immaterial (in Anscombe and Geach 1954, pp. 274-5)Elizabeth is expressing the prevailing mechanistic view as to how causation of bodies works... Causal relations countenanced by contemporary physics can take several forms, not all of which are of the push-pull variety.—David Robb and John Heil, "Mental Causation" in The Stanford Encyclopedia of Philosophy
Biologist, theoretical neuroscientist and philosopher, Walter J. Freeman, suggests that explaining mind-body interaction in terms of "circular causation" is more relevant than linear causation:The restriction of causality to 'efficient causality' lead to the neglect of 'goal-orientation' since it was no longer necessary within [that] framework... Not considering 'goal-orientation' resulted in the neglect of 'embedment' and the consequential presupposition of 'isolation' with separation between brain, body, and environment. Neglecting 'embedment' lead to the equation of perception/action with sensory impression/movement which could be well accounted for by 'efficient causality'. Accordingly, since dominated by 'efficient causality', qualia and intentionality, as related to perception/action rather than to sensory impression/movement, were excluded from science and consequently regarded [as] purely philosophical problems. Analogous to 'final causes', 'formal causes' were eliminated as well... 'Efficient causality' is not compatible with 'embedded coding' [which] is necessarily tied with 'formal causality' and 'final causality'... Finally, the possibility of mental causation remains incompatible with 'efficient causality'. It can, however, be properly described by 'formal and final causality'.—Georg Northoff, Philosophy of the Brain: The Brain Problem
The distinction between "circular causality" and simple feedback is detailed as follows::Through my readings in physics and philosophy, I learned the concept of circular causality, which invokes hierarchical interactions of immense numbers of semiautonomous elements such as neurons, which form nonlinear systems. These exchanges lead to the formation of macroscopic population dynamics that shapes the pattern of activity of the contributing individuals...Circular causality departs so strongly from the classical tenets of necessity, invariance, and precise temporal order that the only reason to call it that is to satisfy the human habitual need for causes. The most subtle shift is the disappearance of agency, which is equivalent to loss of Aristotle's efficient cause...The very strong appeal of agency to explain events may come from the subjective experience of cause and effect that develops early in human life, before the acquisition of language...the question I raise here is whether brains share this property with other material objects in the world. The answer I propose is that assignment of cause and effect to one's self and to others having self-awareness is entirely appropriate, but that investing insensate objects with causation is comparable to investing them with teleology and soul. The further question is: Does it matter whether or not causality is assigned to objects? The answer is "Very much." Several examples are given of scientific errors attributed to thinking in terms of linear causality. The most important, with wide ramifications, is the assumption of universal determinacy, by which the causes of human behavior are limited to environmental and genetic factors, and the causal power of self-determination is excluded from scientific consideration.—Walter J. Freeman, "Consciousness, intentionality and causality" in Does Consciousness Cause Behavior?
Kelso's explanation distinguishes "circular causality" from feedback in linear systems. A further example of this term taken from the field of complex feedback systems is the "slaving principle" (a generalization from analysis of lasers), detailed as follows:But add a few more parts interlaced together and very quickly it becomes impossible to treat the system in terms of feedback circuits. In such complex systems, ... the concept of feedback is inadequate.[...] there is no reference state with which feedback can be compared and no place where comparison operations are performed [...] An order parameter is created by the correlation between the parts, but in turn influences the behavior of the parts. This is what we mean by circular causality.—JA Scott Kelso, Dynamic Patterns: The Self-Organization of Brain and Behavior
Its implications for the mind-body interaction still are under discussion.Note we are dealing here with circular causality. On the one hand the order parameter enslaves the atoms, but on the other hand it is itself generated by the joint action of the atoms...Over the past years, it has been shown that these concepts apply to a large number of quite different physical, chemical and biological systems.—Hermann Haken, Information and Self-Organization: A Macroscopic Approach to Complex Systems
In neuroscience much has been learned about correlations between brain activity and subjective, conscious experiences. Many suggest that neuroscience will ultimately explain consciousness: "...consciousness is a biological process that will eventually be explained in terms of molecular signaling pathways used by interacting populations of nerve cells..." However, this view has been criticized because consciousness has yet to be shown to be a process.  and the "hard problem" of relating consciousness directly to brain activity remains elusive.
Cognitive science today gets increasingly interested in the embodiment of human perception, thinking, and action. Abstract information processing models are no longer accepted as satisfactory accounts of the human mind. Interest has shifted to interactions between the material human body and its surroundings and to the way in which such interactions shape the mind. Proponents of this approach have expressed the hope that it will ultimately dissolve the Cartesian divide between the immaterial mind and the material existence of human beings (Damasio, 1994; Gallagher, 2005). A topic that seems particularly promising for providing a bridge across the mind-body cleavage is the study of bodily actions, which are neither reflexive reactions to external stimuli nor indications of mental states, which have only arbitrary relationships to the motor features of the action (e.g., pressing a button for making a choice response). The shape, timing, and effects of such actions are inseparable from their meaning. One might say that they are loaded with mental content, which cannot be appreciated other than by studying their material features. Imitation, communicative gesturing, and tool use are examples of these kinds of actions.—Georg Goldenberg, "How the Mind Moves the Body: Lessons From Apraxia" in Oxford Handbook of Human Action
 Historical backgroundThe following is a very brief accounting of some contributions to the mind-body problem.
 PlatoPlato(429–347 B.C.E.) argued that, as the body is from the material world, the soul is from the world of ideas and is thus immortal. He believed the soul was temporarily united with the body and would only be separated at death, when it would return to the world of Forms. Since the soul does not exist in time and space, as the body does, it can access universal truths.
For Plato, ideas (or Forms) are the true reality, and are experienced by the soul. The body is for Plato empty in that it can not access the abstract reality of the world; it can only experience shadows. This is determined by Plato's essentially rationalistic epistemology.'Forms'...exist outside of space and time and that are both the objects of knowledge and somehow the cause of whatever transpires in the physical world [...] the immortal soul, in a disembodied state prior to its incarceration in a body, viewed these Forms, a knowledge of which is then recalled by incarcerated souls through a laborious process.—Alan Silverman, Plato's Middle Period Metaphysics and Epistemology
 AristotleFor Aristotle(384–322 BC) mind is a faculty of the soul. Regarding the soul, he said:
- “It is not necessary to ask whether soul and body are one, just as it is not necessary to ask whether the wax and its shape are one, nor generally whether the matter of each thing and that of which it is the matter are one. For even if one and being are spoken of in several ways, what is properly so spoken of is the actuality” (De Anima ii 1, 412b6–9)
 AvicennaIbn Sīnā, (Avicenna) proposed that there are two types of causality (the "being responsible for something else") whereby he categorized Aristotle's four causes. The first kind of causes is that which is included in the effect and is part of it. The second kind of causes does not reside in the effect and is separate from it.
In the first category, Avicenna placed the causa materialis or material cause, (the material out of which something is made), and the causa formalis or formal cause (the shape or form). In the second category of external causes he placed causa efficiencs or efficient cause, (the agent bringing about a change, the usual 'cause' of science as stimulus and response) and the causa finalis or final cause (the purpose or goal).
 DescartesRené Descartes (1596–1650) believed that mind exerted control over the brain via the pineal gland:
My view is that this gland is the principal seat of the soul, and the place in which all our thoughts are formed.—René Descartes, Treatise of man
His posited relation between mind and body is called Cartesian dualism or substance dualism. He held that mind was distinct from matter, but could influence matter. How such an interaction could be exerted remains a contentious issue.[The] mechanism of our body is so constructed that simply by this gland's being moved in any way by the soul or by any other cause, it drives the surrounding spirits towards the pores of the brain, which direct them through the nerves to the muscles; and in this way the gland makes the spirits move the limbs.—René Descartes, Passions of the soul
 KantFor Kant(1724–1804) beyond mind and matter there exists a world of a priori forms, some of which, space and time being examples, are pre-programmed in the brain.
Kant views the mind-body interaction as taking place through forces that may be of different kinds for mind and body....whatever it is that impinges on us from the mind-independent world does not come located in a spatial or a temporal matrix,...The mind has two pure forms of intuition built into it to allow it to... organize this 'manifold of raw intuition'.—Andrew Brook , Kant's view of the mind and consciousness of self: Transcendental aesthetic
 HuxleyFor Huxley(1825-1895) the conscious mind was a by-product of the brain that has no influence upon the brain, a so-called epiphenomenon.
On the epiphenomenalist view, mental events play no causal role. Huxley, who held the view, compared mental events to a steam whistle that contributes nothing to the work of a locomotive.—William Robinson, Epiphenomenalism
 PopperFor Popper (1902-1994) there are three aspects of the mind-body problem: the worlds of mind, matter, and of the creations of the mind, such as mathematics. In his view, the third-world creations of the mind could be interpreted by the second-world mind and used to affect the first-world of matter. An example might be radio, an example of the interpretation of the third-world (Maxwell's electromagnetic theory) by the second-world mind to suggest modifications of the external first world.
The body-mind problem is the question of whether and how our thought processes in World 2 are bound up with brain events in World 1. ...I would argue that the first and oldest of these attempted solutions is the only one that deserves to be taken seriously [namely]: World 2 and World 1 interact, so that when someone reads a book or listens to a lecture, brain events occur that act upon the World 2 of the reader's or listener's thoughts; and conversely, when a mathematician follows a proof, his World 2 acts upon his brain and thus upon World 1. This, then, is the thesis of body-mind interaction.—Karl Popper, Notes of a realist on the body-mind problem
 SearleFor Searle (1932-) the mind-body problem is a false dichotomy, that is, mind is a perfectly ordinary aspect of the brain. In some sense this is also the point of view of Aristotle, outlined above.
According to Searle then, there is no more a mind-body problem that there is a macro-micro economics problem. They are different levels of description of the same set of phenomena. [...] But Searle is careful to maintain that the mental – the domain of qualitative experience and understanding – is autonomous and has no counterpart on the microlevel; any redescription of of these macroscopic features amounts to a kind of evisceration, ...—Joshua Rust, John Searle
 See also
- Chinese room
- Cognitive neuroscience
- Descartes' Error
- Dualism (philosophy of mind)
- Embodied cognition
- Explanatory gap
- Free will
- Ghost in the Machine
- Hard problem of consciousness
- Namarupa (Buddhist concept)
- Neural correlates of consciousness
- Neuroscience of free will
- Philosophical zombie
- Philosophy of artificial intelligence
- Philosophy of mind
- Problem of other minds
- Quantum mind–body problem
- Sacred–profane dichotomy
- Strange loop (self-reflective thoughts)
- The Mind's I (book on the subject)
- Turing test
 Notes and citations
- Descartes, R. (2008). Meditations on First Philosophy (Michael Moriarity translation of 1641 ed.). Oxford University Press. http://books.google.com/books?id=n2PHP3bf5d0C&printsec=frontcover.
- Crane, Tim and Patterson, Sarah (2001). "Introduction". In Crane, Tim and Patterson, Sarah, eds. History of the Mind-Body Problem. Psychology Press. pp. 1-2. ISBN 0415242363. http://books.google.com/books?id=OcKt0hNHAc8C&printsec=frontcover.
- Robert M. Young (1996). "The mind-body problem". In RC Olby, GN Cantor, JR Christie, MJS Hodges, eds. Companion to the History of Modern Science (Paperback reprint of Routledge 1990 ed.). Taylor and Francis. pp. 702-11. ISBN 0415145783. http://human-nature.com/rmyoung/papers/pap102h.html.
- Robinson, Howard (Nov 3, 2011). "Dualism". In Edward N. Zalta, ed. The Stanford Encyclopedia of Philosophy (Winter 2011 Edition). http://plato.stanford.edu/archives/win2011/entries/dualism/.
- Henrik Lagerlund (2010). "Introduction". In Henrik Lagerlund, ed. Forming the Mind: Essays on the Internal Senses and the Mind/Body Problem from Avicenna to the Medical Enlightenment (Paperback reprint of 2007 ed.). Springer Science+Business Media. p. 3. ISBN 9048175305. http://books.google.com/books?id=IV-dcQAACAAJ.
- Bryan S. Turner (2008). The Body and Society: Explorations in Social Theory (3rd ed.). Sage Publications. p. 78. ISBN 1412929873. http://books.google.com/books?id=FYKjzsc6SkAC. "...a rejection of any dualism between mind and body, and a consequent insistence on the argument that the body is never simply a physical object but always an embodiment of consciousness."
- Kim, Jaegwan (1995). "Emergent properties". In Honderich, Ted. Problems in the Philosophy of Mind. Oxford Companion to Philosophy. Oxford: Oxford University Press. p. 240. http://books.google.com/books?id=sI4YAAAAIAAJ&dq=editions:qiO-uKvXxpQC.
- Pinel, J. (2009). Psychobiology (7th ed.). Pearson/Allyn and Bacon. ISBN 020554892X. http://books.google.com/books?id=eW1FAQAAIAAJ.
- LeDoux, J. (2002). The Synaptic Self: How Our Brains Become Who We Are. Viking Penguin. ISBN 88-7078-795-8. http://books.google.com/books?id=3Zpr6NOy5tsC&printsec=frontcover.
- Russell, S. and Norvig, P. (2010). Artificial Intelligence: A Modern Approach (3rd ed.). Prentice Hall. ISBN 0136042597. http://books.google.com/books?id=8jZBksh-bUMC.
- Dawkins, R. (2006). The Selfish Gene (3rd ed.). Oxford University Press. ISBN 0199291144. http://books.google.com/books?id=0ICKantUfvoC&printsec=frontcover.
- Robb, David; Heil, John (2009). "Mental Causation". In Edward N. Zalta. The Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/archives/sum2009/entries/mental-causation/.
- Georg Northoff (2004). Philosophy of the Brain: The Brain Problem (Volume 52 of Advances in Consciousness Research ed.). John Benjamins Publishing. pp. 137-139. ISBN 1588114171. http://books.google.com/books?id=CJq4QDixIg0C&pg=PT148&lpg=PT148.
- Walter J Freeman (2009). "Consciousness, intentionality and causality". In Susan Pockett, WP Banks, Shaun Gallagher, eds. Does Consciousness Cause Behavior?. MIT Press. pp. 4-5,88-90. ISBN 0262512572. http://books.google.com/books?id=G5CaTnNksgkC&pg=PA4. "Walter Freeman, with his usual originality, suggest that we may be looking at the whole thing in completely the wrong way when we ask whether consciousness causes or is caused by neural activity. He suggests that circular causation is a more relevant concept in this regard than linear causation. Consciousness and neural activity are certainly interdependent, but it is impossible in principle to say that either causes the other. Thus the whole concept of consciousness as agent is simply a misreading of the true situation." Quote is a summary of Freeman's position by the editors.
- J. A. Scott Kelso (1995). Dynamic Patterns: The Self-Organization of Brain and Behavior. MIT Press. pp. 9,16. ISBN 0262611317. http://books.google.com/books?id=zpjejjytkiIC&pg=PA16&lpg=PA16.
- Hermann Haken (2006). Information and Self-Organization: A Macroscopic Approach to Complex Systems (3rd ed ed.). Springer. pp. 25-26. ISBN 3540330216. http://books.google.com/books?id=tAfj4-xzyGwC&pg=PA25&lpg=PA25.
- Eric R. Kandel (2007). In Search of Memory: The Emergence of a New Science of Mind. WW Norton. pp. p. 9. ISBN 0393329372. http://books.google.com/books?id=PFnRwWXzypgC&pg=PA9&lpg=PA9.
- Oswald Hanfling (2002). Wittgenstein and the Human Form of Life. Psychology Press. pp. 108-109. ISBN 0415256453. http://books.google.com/books?id=TRIkWPqy-JgC&pg=PA108&lpg=PA108.
- A term attributed to David Chalmers by Eugene O Mills (1999). "Giving up on the hard problem of consciousness". In Jonathan Shear, ed. Explaining Consciousness: The Hard Problem. MIT Press. pp. 109. ISBN 026269221X. http://books.google.com/books?id=t4KNDxsj7fcC&pg=PA109&lpg=PA109.
- Goldenberg, Georg (2008). "Chapter 7, How the Mind Moves the Body: Lessons From Apraxia". In Morsella, E.; Bargh, J.A. and Gollwitzer, P.M.. Oxford Handbook of Human Action. Social Cognition and Social Neuroscience. Oxford University Press, USA. p. 136. ISBN 9780195309980. LCCN 2008004997. http://books.google.com/books?id=zFP1AZYlNmcC&pg=PA136.
- Silverman, Allan (December 10, 2008). "Plato's Middle Period Metaphysics and Epistemology". In Edward N. Zalta (ed.). The Stanford Encyclopedia of Philosophy (Summer 2012 Edition). http://plato.stanford.edu/archives/sum2012/entries/plato-metaphysics/. .
- Shields, Christopher. "Aristotle's Psychology". In Edward N. Zalta (ed.). The Stanford Encyclopedia of Philosophy (Spring 2011 Edition). http://plato.stanford.edu/archives/spr2011/entries/aristotle-psychology/.
- Nader El-Bizri (2000). The Phenomenological Quest Between Avicenna and Heidegger. Global Academic Publishing. pp. 97-98. ISBN 1586840053. http://books.google.com/books?id=DEVc6o-mOp4C&pg=PA97&lpg=PA97.
- Lokhorst, Gert-Jan (Nov 5, 2008). "Descartes and the Pineal Gland". In Edward N. Zalta, ed. The Stanford Encyclopedia of Philosophy (Summer 2011 Edition). http://plato.stanford.edu/archives/sum2011/entries/pineal-gland/. Lokhorst quotes Descartes in his Treatise of man
- Lokhorst, Gert-Jan (Nov 5, 2008). "Descartes and the Pineal Gland". In Edward N. Zalta, ed. The Stanford Encyclopedia of Philosophy (Summer 2011 Edition). http://plato.stanford.edu/archives/sum2011/entries/pineal-gland/. Lokhorst quotes Descartes in his Passions of the soul
- Brook, Andrew (October 20, 2008). "Kant's View of the Mind and Consciousness of Self". In Edward N. Zalta (ed.). The Stanford Encyclopedia of Philosophy (Winter 2011 Edition). http://plato.stanford.edu/archives/win2011/entries/kant-mind/.
- Eric Watkins (2004). "Causality in context". Kant and the Metaphysics of Causality. Cambridge University Press. p. 108. ISBN 0521543614. http://books.google.com/books?id=XIIsaGoHshoC&pg=PA108&lpg=PA108.
- Robinson, William, (January 27, 2011). "Epiphenomenalism". In Edward N. Zalta (ed.). The Stanford Encyclopedia of Philosophy (Summer 2012 Edition). http://plato.stanford.edu/archives/sum2012/entries/epiphenomenalism/.
- Karl Raimund Popper (1999). "Notes of a realist on the body-mind problem". All Life is Problem Solving (A lecture given in Mannheim, 8 May, 1972 ed.). Psychology Press. pp. 29 ff. ISBN 0415174864. http://books.google.com/books?id=Pa3cZYwdq28C&pg=PA269&lpg=PA29. "The body-mind relationship...includes the problem of man's position in the physical world...'World 1'. The world of conscious human processes I shall call 'World 2', and the world of the objective creations of the human mind I shall call 'World 3'."
- Joshua Rust (2009). John Searle. Continuum International Publishing Group. pp. 27-28. ISBN 0826497527. http://books.google.com/books?id=9CWdaJq-apUC&pg=PA28&lpg=PA28.
- Turner, Bryan S. Body and Society: Exploration in social theory 1996
- Kim, J., "Mind–Body Problem", Oxford Companion to Philosophy. Ted Honderich (ed.). Oxford:Oxford University Press. 1995.
- Jaegwon Kim (2010). Essays in the Metaphysics of Mind. Oxford University Press. ISBN 019162506X. http://books.google.com/books?id=Ms6gBG-o65MC&printsec=frontcover.
- Feigl, Herbert (1958). "The 'Mental' and the 'Physical'". In Feigl, Herbert; Scriven, Michael; Maxwell, Grover. Concepts, Theories, and the Mind-Body Problem. Minnesota Studies in the Philosophy of Science. 2. Minneapolis: University of Minnesota Press. pp. 370–457. http://ditext.com./feigl/mp/mp.html.