The mind-body problem is the philosophical inquiry into the relationship between the mind and the body, or between mental properties and physical properties.
If one rejects analytical accounts of mental predicates, such as behaviorism or functionalism, the conceivability argument suggests that the dependence of the mind on the body does not follow the standard models of dependence found in other scientific cases.
Physicalists generally accept David Hume's bundle theory unless they wish to ascribe the unity of the mind to the brain or the organism as a whole.
Sydney Shoemaker authored 'Identity, Cause, and Mind', published by Cambridge University Press in 1984.
Common sense suggests that the mind and body interact because everyday experience indicates that thoughts and feelings are sometimes caused by bodily events and sometimes cause bodily responses.
Before Saul Kripke's work in 1972/1980, philosophers generally believed in contingent identity, which made the transition from the possibility of a mind existing without a body to the conclusion that the mind is a different entity from the body seem invalid.
The conceivability argument establishes a prima facie case that the mind possesses only a causal ontological dependence on the body.
David Hume claimed the mind is nothing but a 'bundle' or 'heap' of impressions and ideas, which are particular mental states or events without an owner.
Interactionism is the view that the mind and body, or mental events and physical events, causally influence each other.
David Hume described the mind as a theatre, stating: "The mind is a kind of theatre where several perceptions successively make their appearance; pass, re-pass, glide away and mingle in an infinite variety of postures and situations."
To avoid ontological dualism, the mind possessing a perspective must be considered part of the physical reality it observes.
Psychology is widely considered an irreducible special science, meaning that if its subject matter is physical, it requires a mind to perceive that matter as psychological.
René Descartes believed in a natural form of interaction between the immaterial mind and the material body.
Averill and Keating (1981) suggested that the mind might influence the distribution of energy within a physical system without altering the total quantity of energy.
Some theorists, including Hodgson (1988) and Stapp (1993), argue that quantum indeterminacy manifests directly at a high level when acts of observation collapse the wave function, suggesting the mind may play a direct role in affecting the state of the world.
Dualism defines the mind in contrast to the body, though the specific aspects of the mind that receive focus have shifted throughout history.
The zombie argument establishes only property dualism, and a property dualist might consider disembodied existence inconceivable if they believe the identity of a mind through time depends on its relation to a body.
Substance dualism faces the problem of explaining the nature of an immaterial substance that accounts for the unity of the mind.
G. H. von Wright authored the article 'On mind and matter', published in the Journal of Theoretical Biology in 1994.
David Hume's bundle theory is a theory about the nature of the unity of the mind and is not necessarily dualist.
The perspectivality of special sciences suggests a link to property dualism because having a perspective is a psychological state, implying that irreducible special sciences presuppose the existence of a mind.
Herbert Feigl (1958) defines 'nomological danglers' as brute facts that are added to the body of integrated physical law, specifically referring to the laws linking mind and brain.
Bundle dualism is a position where the mind is viewed as a bundle of impressions and ideas, and it is a special case of the general bundle theory of substance, which posits that objects are organized collections of properties.
Gilbert Ryle described the mind, as conceived by the dualist, as a 'ghost in a machine'.
Gottfried Wilhelm Leibniz proposed that God set up the universe so that the mind and body always behave as if they were interacting, without requiring specific intervention on each occasion.
For the mind, mere causal connection is insufficient to explain the unity of the bundle; some further relation of co-consciousness is required.
The argument against the bundle theory of the self states that if the bundle theory were true, it should be possible to identify mental events independently of or prior to identifying the person or mind to which they belong; since it is not possible to identify mental events in this way, the bundle theory is false.
While David Hume accepted the consequence that mental contents could exist alone, most philosophers regard the idea of a mind consisting of a lone pain or red after-image as absurd.
The metaphor of the mind as a theatre is associated with the Cartesian picture, which invokes a medium, arena, or field to bind different contents together into a single mind.
Substance dualism posits that the mind is an immaterial substance that exists over and above its immaterial states, rather than being merely a collection of thoughts.
René Descartes identified the pineal gland as the site of interaction between the mind and the body, primarily because it is not duplicated on both sides of the brain and thus serves as a candidate for a unique, unifying function.
Nicolas Malebranche argued that natural interaction between mind and body was impossible, requiring God to intervene specifically on each occasion where interaction was needed.
The problem of embodiment asks what it means for a mind to be housed in a body and what it means for a body to belong to a particular subject.
Explaining the nature of the unity of the immaterial mind is a challenge for both those who believe the mind is a substance and those who believe it is a bundle of properties.
According to the mechanist view, the world is 'closed under physics,' meaning everything that happens follows from and is in accord with the laws of physics, leaving no scope for interference in the physical world by the mind.
George Berkeley rejected the existence of material substance because he rejected the existence of anything outside the mind.
The mind must be simple, and this is only possible if the mind is something like a Cartesian substance, because physical constitution allows for degrees and overlap which are not applicable to the subjective point of view.
Modern Humeans, including Derek Parfit (1971; 1984) and Barry Dainton (2008), replace the metaphor of the mind as a theatre with the concept of a co-consciousness relation.
If an irreducible mind is considered physical, it creates a circular dependency where a mind is required to perceive that mind as physical.
Arguments against physicalism are also arguments for the irreducible and immaterial nature of the mind, and consequently, arguments for dualism.
If the mind is a bundle of properties without a mental substance, the unity of the mind must be explained by postulating a primitive relation of co-consciousness between the various elements.
René Descartes was a substance dualist who believed in two distinct kinds of substance: matter, which is defined by spatial extension, and mind, which is defined by the property of thinking.
In the Appendix to his work, David Hume expressed dissatisfaction with his own bundle theory of the self because he could not reconcile two principles: that all distinct perceptions are distinct existences, and that the mind never perceives any real connection between distinct existences.
René Descartes' conception of the relationship between the mind and the body differed significantly from the Aristotelian tradition.
D.M. Armstrong (1968) objects to bundle theories by arguing that if individual mental contents are the elements of a mind, those contents should be able to exist alone, similar to individual bricks from a house.
Property dualism regarding the mind is defended by those who argue that the qualitative nature of consciousness is a genuinely emergent phenomenon rather than merely a way of categorizing brain states or behavior.
Proponents of the dualist argument claim that one can know a priori through introspection that the mind is not more-than-causally dependent on a radically different nature, such as a brain or body.
George Berkeley suggested that once genuine interaction between mind and body is ruled out, it is best to allow that God creates the physical world directly within the mental realm as a construct of experience.
Bundle theory posits that the mind consists of the objects of awareness and the co-consciousness relations that hold between them, with the nexus of these relations constituting the sense of the subject and the act of awareness.
David Hume believed that an impression might 'float free' from the mind to which it belonged, implying that the identity conditions of individual mental states are independent of the identity of the person who possesses them.
Anthony Kenny (1989) argues that Aristotle's theory of the mind as a form is similar to Gilbert Ryle's (1949) account, as both equate the soul to the dispositions possessed by a living body.