Interactionism (philosophy of mind)

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Interactionism or interactionist dualism is the theory in the philosophy of mind which holds that matter and mind are two distinct and independent substances that exert causal effects on one another. [1] It is one type of dualism, traditionally a type of substance dualism though more recently also sometimes a form of property dualism. Many philosophers and scientists have responded to this theory with arguments both supporting and opposing its relevance to life and whether the theory corresponds to reality.

Contents

Proponents

Rene Descartes's illustration of dualism. Inputs are passed on by the sensory organs to the epiphysis in the brain and from there to the immaterial spirit. Descartes mind and body.gif
René Descartes's illustration of dualism. Inputs are passed on by the sensory organs to the epiphysis in the brain and from there to the immaterial spirit.

René Descartes

Interactionism was propounded by the French rationalist philosopher René Descartes (1596–1650), and continues to be associated with him. Descartes posited that the body, being physical matter, was characterized by spatial extension but not by thought and feeling, while the mind, being a separate substance, had no spatial extension but could think and feel. [2] Nevertheless, he maintained that the two interacted with one another, suggesting that this interaction occurred in the pineal gland of the brain. [3]

Development of interactionism

In the 20th century, its most significant defenders have been the noted philosopher of science Karl Popper and the neurophysiologist John Carew Eccles. [4] Popper in fact divided reality into three "worlds"—the physical, the mental, and objective knowledge (outside the mind)—all of which interact, [5] and Eccles adopted this same "trialist" form of interactionism. [6] Other notable recent philosophers to take an interactionist stance have been Richard Swinburne, John Foster, David Hodgson, and Wilfrid Sellars, in addition to the physicist Henry Stapp. [7]

In his 1996 book The Conscious Mind , David Chalmers questioned interactionism. In 2002 he listed it along with epiphenomenalism and what he calls "Type-F Monism" as a position worth examining. Rather than invoking two distinct substances, he defines interactionism as the view that "microphysics is not causally closed, and that phenomenal properties play a causal role in affecting the physical world." (See property dualism.) He argues the most plausible place for consciousness to impact physics is the collapse of the wave function in quantum mechanics. [7]

The New Catholic Encyclopedia argues that a non-physical mind and mind-body interaction follow necessarily from the Catholic doctrines of the soul and free will. [8]

Objections

Problem of causal interaction

Today the problem of causal interaction is frequently viewed as a conclusive argument against interactionism. [9] On the other hand, it has been suggested that given many disciplines deal with things they do not entirely understand, dualists not entirely understanding the mechanism of mind-body interaction need not be seen as definitive refutation. [9] The idea that causation necessarily depends on push-pull mechanisms (which would not be possible for a substance that did not occupy space) is also arguably based on obsolete conceptions of physics. [2]

Objection from Princess Elizabeth of Bohemia

One objection often posed to interactionism is the problem of causal interaction – how the two different substances the theory posits, the mental and the physical, can exert an impact on one another. This objection was initially made by Elisabeth, Princess of Bohemia and is known as Princess Elisabeth's objection. She questions how something immaterial can make contact with the physical world. An example of a physical-physical interaction is how when a cue ball hits another billiards ball, it causes it to move. Princess Elisabeth questioned how a mental occurrence, such as intention, can cause a finger to move if immaterial things never come into direct contact with the physical world. [10]

Occasionalism

One objection often posed to interactionism is the problem of causal interaction – how the two different substances the theory posits, the mental and the physical, can exert an impact on one another. Descartes' theory that interaction between the mind and the physical world occurred in the pineal gland was seen as inadequate by a number of philosophers in his era, who offered alternate views: Nicholas Malebranche suggested occasionalism, according to which mind and body appear to interact but are in fact moved separately by God, while Gottfried Leibniz argued in The Monadology that mind and body are in a pre-established harmony. [3] On the other hand, Baruch Spinoza rejected Descartes' dualism and proposed that mind and matter were in fact properties of a single substance, [3] thereby prefiguring the modern perspective of neutral monism.

The problem of mental causation is also discussed in the context of other positions on the mind-body problem, such as property dualism and anomalous monism. [2]

Compatibility with the conservation of energy

A more recent related objection is the argument from physics, which argues that a mental substance impacting the physical world would contradict principles of physics. [1] In particular, if some external source of energy is responsible for the interactions, it would violate the law of conservation of energy. [11] Two main responses to this have been to suggest the mind influences the distribution but not the quantity of energy in the brain and to deny that the brain is a causally closed system in which conservation of energy would apply. [1] [8] It could of course also be argued that the law of conservation of energy is false in systems which realize a mind.

Causal closure

Taking the argument a step further, it has been argued that because physics fully accounts for the causes of all physical movements, there can be no place for a non-physical mind to play a role. [2] The principle, in slightly different iterations, has variously been called causal closure, completeness of the physical, physical closure, and physical comprehensiveness. [2] This has been the foremost argument against interactionism in contemporary philosophy. [7]

Some philosophers have suggested the influence of the mind on the body could be reconciled with deterministic physical laws by proposing the mind's impacts instead take place at points of quantum indeterminacy. [9] Karl Popper and John Eccles, as well as the physicist Henry Stapp, have theorized that such indeterminacy may apply at the macroscopic scale. [4] (See quantum mind.) However, Max Tegmark has argued that classical and quantum calculations show that quantum decoherence effects do not play a role in brain activity. [12] David Chalmers has noted (without necessarily endorsing) a second possibility within quantum mechanics, that consciousness' causal role is to collapse the wave function as per the Von Neumann-Wigner interpretation of quantum mechanics. [13] He acknowledges this is at odds with the interpretations of quantum mechanics held by most physicists, but notes, "There is some irony in the fact that philosophers reject interactionism on largely physical grounds (it is incompatible with physical theory), while physicists reject an interactionist interpretation of quantum mechanics on largely philosophical grounds (it is dualistic). Taken conjointly, these reasons carry little force...". [7]

There remains a literature in philosophy and science, albeit a much-contested one, that asserts evidence for emergence in various domains, which would undermine the principle of causal closure. [2] (See emergentism.) Another option that has been suggested is that the interaction may involve dark energy, dark matter or some other currently unknown scientific process. [14]

Causal Overdetermination

Another possible resolution is akin to parallelism—Eugene Mills holds that behavioral events are causally overdetermined, and can be explained by either physical or mental causes alone. An overdetermined event is fully accounted for by multiple causes at once. To imagine this argument, Amy Kind refers to a case from Mission Impossible: Rogue Nation, where three snipers each fire a bullet into an Austrian Chancellor's heart. Regardless if the Chancellor was shot with three bullets or one, the outcome was inevitable. This is an example of overdetermination because it states that both mental and physical causes invoke reactions and like the bullets, no matter if there is a physical cause or a mental cause, the outcome is the same. However, J. J. C. Smart and Paul Churchland have argued that if physical phenomena fully determine behavioral events, then by Occam's razor a non-physical mind is unnecessary. Andrew Melnyk argues that overdetermination would require an "intolerable coincidence." However, Vilanayur S. Ramachandran and William Hirstein (1997) argue that Occam's razor is not useful for scientific discovery. They exemplify the above with the discovery of relativity in physics, which was not the product of accepting Occam's razor but rather of rejecting it and asking the question of whether it could be that a deeper generalization, not required by the currently available data, was true and allowed for unexpected predictions. Most scientific discoveries arise, these authors argue, from ontologically promiscuous conjectures that do not come from current data. [15]

While causal closure remains a key obstacle for interactionism, it is not relevant to all forms of dualism; epiphenomenalism and parallelism are unaffected as they do not posit that the mind affects the body. [2]

Relationship to other positions

Four varieties of dualist causal interaction. The arrows indicate the direction of causations. Mental and physical states are shown in red and blue, respectively. DualismCausationViews3.svg
Four varieties of dualist causal interaction. The arrows indicate the direction of causations. Mental and physical states are shown in red and blue, respectively.

Interactionism can be distinguished from competing dualist theories of causation, including epiphenomenalism (which admits causation, but views causation as unidirectional rather than bidirectional), and parallelism (which denies causation, while seeking to explain the semblance of causation by other means such as pre-established harmony or occasionalism). [1]

In The Conscious Mind, David Chalmers argued that regardless of the mechanism by which the mental might impact the physical if interactionism were true, there was a deeper conceptual issue: the chosen mechanism could always be separated from its phenomenal component, leading to simply a new form of epiphenomenalism. [13] Later, he suggested that while the causal component could be separated, interactionism was like "type-F monism" (Russellian monism, panpsychism, and panprotopsychism) in that it gave entities externally characterized by physical relationships the additional intrinsic feature of conscious properties. [7]

See also

Related Research Articles

Epiphenomenalism is a position on the mind–body problem which holds that physical and biochemical events within the human body are the sole cause of mental events. According to this view, subjective mental events are completely dependent for their existence on corresponding physical and biochemical events within the human body, yet themselves have no influence over physical events. The appearance that subjective mental states influence physical events is merely an illusion. For instance, fear seems to make the heart beat faster, but according to epiphenomenalism the biochemical secretions of the brain and nervous system —not the experience of fear—is what raises the heartbeat. Because mental events are a kind of overflow that cannot cause anything physical, yet have non-physical properties, epiphenomenalism is viewed as a form of property dualism.

In philosophy, physicalism is the metaphysical thesis that "everything is physical", that there is "nothing over and above" the physical, or that everything supervenes on the physical. Physicalism is a form of ontological monism—a "one substance" view of the nature of reality as opposed to a "two-substance" (dualism) or "many-substance" (pluralism) view. Both the definition of "physical" and the meaning of physicalism have been debated.

<span class="mw-page-title-main">Mind–body dualism</span> Philosophical theory

In the philosophy of mind, mind–body dualism denotes either the view that mental phenomena are non-physical, or that the mind and body are distinct and separable. Thus, it encompasses a set of views about the relationship between mind and matter, as well as between subject and object, and is contrasted with other positions, such as physicalism and enactivism, in the mind–body problem.

In philosophy of mind, functionalism is the thesis that mental states are constituted solely by their functional role, which means, their causal relations with other mental states, sensory inputs and behavioral outputs. Functionalism developed largely as an alternative to the identity theory of mind and behaviorism.

The knowledge argument is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" (1982) and extended in "What Mary Didn't Know" (1986). The experiment describes Mary, a scientist who exists in a black and white world where she has extensive access to physical descriptions of color, but no actual human perceptual experience of color. The central question of the thought experiment is whether Mary will gain new knowledge when she goes outside the black and white world and experiences seeing in color.

<span class="mw-page-title-main">Panpsychism</span> View that mind is a fundamental feature of reality

In the philosophy of mind, panpsychism is the view that the mind or a mindlike aspect is a fundamental and ubiquitous feature of reality. It is also described as a theory that "the mind is a fundamental feature of the world which exists throughout the universe." It is one of the oldest philosophical theories, and has been ascribed to philosophers including Thales, Plato, Spinoza, Leibniz, William James, Alfred North Whitehead, Bertrand Russell, and Galen Strawson. In the 19th century, panpsychism was the default philosophy of mind in Western thought, but it saw a decline in the mid-20th century with the rise of logical positivism. Recent interest in the hard problem of consciousness and developments in the fields of neuroscience, psychology, and quantum physics have revived interest in panpsychism in the 21st century.

The hard problem of consciousness is the problem of explaining why and how humans have qualia or phenomenal experiences. This is in contrast to the "easy problems" of explaining the physical systems that give us and other animals the ability to discriminate, integrate information, and so forth. These problems are seen as relatively easy because all that is required for their solution is to specify the mechanisms that perform such functions. Philosopher David Chalmers writes that even once we have solved all such problems about the brain and experience, the hard problem will still persist.

A philosophical zombie or p-zombie argument is a thought experiment in philosophy of mind that imagines a hypothetical being that is physically identical to and indistinguishable from a normal person but does not have conscious experience, qualia, or sentience. For example, if a philosophical zombie were poked with a sharp object it would not inwardly feel any pain, yet it would outwardly behave exactly as if it did feel pain, including verbally expressing pain. Relatedly, a zombie world is a hypothetical world indistinguishable from our world but in which all beings lack conscious experience.

In philosophy, emergentism is the belief in emergence, particularly as it involves consciousness and the philosophy of mind. A property of a system is said to be emergent if it is a new outcome of some other properties of the system and their interaction, while it is itself different from them. Within the philosophy of science, emergentism is analyzed both as it contrasts with and parallels reductionism.

<span class="mw-page-title-main">Property dualism</span> Category of positions in the philosophy of mind

Property dualism describes a category of positions in the philosophy of mind which hold that, although the world is composed of just one kind of substance—the physical kind—there exist two distinct kinds of properties: physical properties and mental properties. In other words, it is the view that non-physical, mental properties exist in, or naturally supervene upon, certain physical substances.

Jaegwon Kim was a Korean-American philosopher. At the time of his death, Kim was an emeritus professor of philosophy at Brown University. He also taught at several other leading American universities during his lifetime, including the University of Michigan, Cornell University, the University of Notre Dame, Johns Hopkins University, and Swarthmore College. He is best known for his work on mental causation, the mind-body problem and the metaphysics of supervenience and events. Key themes in his work include: a rejection of Cartesian metaphysics, the limitations of strict psychophysical identity, supervenience, and the individuation of events. Kim's work on these and other contemporary metaphysical and epistemological issues is well represented by the papers collected in Supervenience and Mind: Selected Philosophical Essays (1993).

In the philosophy of mind, psychophysical parallelism is the theory that mental and bodily events are perfectly coordinated, without any causal interaction between them. As such, it affirms the correlation of mental and bodily events, but denies a direct cause and effect relation between mind and body. This coordination of mental and bodily events has been postulated to occur either in advance by means of God or at the time of the event or, finally, according to Baruch Spinoza's Ethics, mind and matter are two of infinite attributes of the only Substance-God, which go as one without interacting with each other. On this view, mental and bodily phenomena are independent yet inseparable, like two sides of a coin.

<span class="mw-page-title-main">Cartesian materialism</span>

In philosophy of mind, Cartesian materialism is the idea that at some place in the brain, there is some set of information that directly corresponds to our conscious experience. Contrary to its name, Cartesian materialism is not a view that was held by or formulated by René Descartes, who subscribed rather to a form of substance dualism.

<span class="mw-page-title-main">Type physicalism</span> Theory in the philosophy of mind

Type physicalism is a physicalist theory in the philosophy of mind. It asserts that mental events can be grouped into types, and can then be correlated with types of physical events in the brain. For example, one type of mental event, such as "mental pains" will, presumably, turn out to be describing one type of physical event.

Physical causal closure is a metaphysical theory about the nature of causation in the physical realm with significant ramifications in the study of metaphysics and the mind. In a strongly stated version, physical causal closure says that "all physical states have pure physical causes" — Jaegwon Kim, or that "physical effects have only physical causes" — Agustin Vincente, p. 150.

The problem of mental causation is a conceptual issue in the philosophy of mind. That problem, in short, is how to account for the common-sense idea that intentional thoughts or intentional mental states are causes of intentional actions. The problem divides into several distinct sub-problems, including the problem of causal exclusion, the problem of anomalism, and the problem of externalism. However, the sub-problem which has attracted most attention in the philosophical literature is arguably the exclusion problem.

<span class="mw-page-title-main">Philosophy of mind</span> Branch of philosophy concerned with the nature of the mind

Philosophy of mind is a branch of philosophy that studies the ontology and nature of the mind and its relationship with the body. The mind–body problem is a paradigmatic issue in philosophy of mind, although a number of other issues are addressed, such as the hard problem of consciousness and the nature of particular mental states. Aspects of the mind that are studied include mental events, mental functions, mental properties, consciousness and its neural correlates, the ontology of the mind, the nature of cognition and of thought, and the relationship of the mind to the body.

<span class="mw-page-title-main">Mind–body problem</span> Open question in philosophy of how abstract minds interact with physical bodies

The mind–body problem is a philosophical debate concerning the relationship between thought and consciousness in the human mind, and the brain as part of the physical body. The debate goes beyond addressing the mere question of how mind and body function chemically and physiologically. Interactionism arises when mind and body are considered as distinct, based on the premise that the mind and the body are fundamentally different in nature.

<i>The Conscious Mind</i> 1996 philosophy book by David Chalmers

The Conscious Mind: In Search of a Fundamental Theory was published in 1996, and is the first book written by David Chalmers, an Australian philosopher specialising in philosophy of mind. Although the book has been greatly influential, Chalmers maintains that it is "far from perfect", as most of it was written as part of his PhD dissertation after "studying philosophy for only four years".

The von Neumann–Wigner interpretation, also described as "consciousness causes collapse", is an interpretation of quantum mechanics in which consciousness is postulated to be necessary for the completion of the process of quantum measurement.

References

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