Causal closure

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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, [1] or that "physical effects have only physical causes" — Agustin Vincente, p. 150. [2]

Metaphysics Branch of philosophy dealing with the nature of reality

Metaphysics is the branch of philosophy that examines the fundamental nature of reality, including the relationship between mind and matter, between substance and attribute, and between possibility and actuality. The word "metaphysics" comes from two Greek words that, together, literally mean "after or behind or among [the study of] the natural". It has been suggested that the term might have been coined by a first century CE editor who assembled various small selections of Aristotle’s works into the treatise we now know by the name Metaphysics.

A physical property is any property that is measurable, whose value describes a state of a physical system. The changes in the physical properties of a system can be used to describe its changes between momentary states. Physical properties are often referred to as observables. They are not modal properties. Quantifiable physical property is called physical quantity.

Philosophy of mind branch of philosophy on the nature of the mind

Philosophy of mind is a branch of philosophy that studies the ontology, nature, and relationship of the mind to the body. The mind–body problem is a paradigm issue in philosophy of mind, although 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, the ontology of the mind, the nature of thought, and the relationship of the mind to the body.


Those who accept the theory tend, in general although not exclusively, to the physicalist view that all entities that exist are physical entities. As Karl Popper says, "The physicalist principle of closedness of the physical ... is of decisive importance and I take it as the characteristic principle of physicalism or materialism." [3]


Physical causal closure has stronger and weaker formulations. [4]

The stronger formulations assert that no physical event has a cause outside the physical domain — Jaegwon Kim. [1] That is, they assert that for physical events, causes other than physical causes do not exist. (Physical events that are not causally determined may be said to have their objective chances of occurrence determined by physical causes.) [5]

Weaker forms of the theory state that "Every physical event has a physical cause." — Barbara Montero, [4] or that "Every physical effect (that is, caused event) has physical sufficient causes" — Agustin Vincente, [2] (According to Vincente, a number of caveats have to be observed, among which is the postulate that "physical entities" are entities postulated by a true theory of physics, a theory of which we are ignorant today, and that such a true theory "will not include mental (or in general, dubious) concepts" (Note 5, p. 168). [2] ) or that "if we trace the causal ancestry of a physical event we need never go outside the physical domain." — Jaegwon Kim. [1] Weaker forms of physical causal closure are synonymous with the causal completeness, [6] the notion that "Every physical effect that has a sufficient cause has a sufficient physical cause." [5] That is, weaker forms allow that in addition to physical causes, there may be other kinds of causes for physical events.

The notion of reductionism supplements physical causal closure with the claim that all events ultimately can be reduced to physical events. Under these circumstances, mental events are a subset of physical events and caused by them. [7]


Physical causal closure is especially important when considering dualist theories of mind. If no physical event has a cause outside the physical realm, it would follow that non-physical mental events would be causally impotent in the physical world. However, as Kim has agreed, it seems intuitively problematic to strip mental events of their causal power. [1] Only epiphenomenalists would agree that mental events do not have causal power, but epiphenomenalism is objectionable to many philosophers. One way of maintaining the causal powers of mental events is to assert token identity non-reductive physicalism—that mental properties supervene on neurological properties. That is, there can be no change in the mental without a corresponding change in the physical. Yet this implies that mental events can have two causes (physical and mental), a situation which apparently results in overdetermination (redundant causes), and denies the strong physical causal closure. [1] Kim argues that if the strong physical causal closure argument is correct, the only way to maintain mental causation is to assert type identity reductive physicalism—that mental properties are neurological properties. [7]


The validity of the physical causal closure has long been debated. [8] In modern times, it has been pointed out that science is based on removing the subject from investigations, and by seeking objectivity. This outsider status for the observer, a third-person perspective, is said by some philosophers to have automatically severed science from the ability to examine subjective issues like consciousness and free will. [9] [10] [11] A different attack upon the physical causal closure discussed by Hodgson is to claim science itself does not support the physical causal closure. [12] Some philosophers have criticized the argument for the physical causal closure by supporting teleology and mental-to-physical causation via a soul. [13]

Ignoring phenomena

There seem prima facie to be irreducible purpose-based (or teleological) explanations of some natural phenomena. For instance, the movement of a writer's fingers on the keyboard and a reader's eyes across the screen is irreducibly explained in reference to the goal of writing an intelligible sentence or of learning about the physical causal closure arguments, respectively. On the face of it, an exclusively non-teleological (descriptive) account of the neurological and biological features of hand movement and eye movement misses the point. To say, "I am moving my fingers because my brain signals are triggering muscle motion in my arms" is true, but does not exhaustively explain all the causes. Both are causes. In Aristotelian terms, a neurological account explains the efficient cause, while the purpose-based account explains the final cause. [14]

The physical causal closure thesis challenges this account. It attempts to reduce all teleological final (and formal) causes to efficient causes. Goetz and Taliaferro urge that this challenge is unjustified, partly because it would imply that the real cause of arguing for the physical causal closure is neurobiological activity in the brain, not (as we know it is) the purpose-based attempt to understand the world and explain it to others.

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Epiphenomenalism is a position on the mind–body problem which holds that physical and biochemical events within the human body are causal with respect to 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 and themselves have no causal efficacy on 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.

Free will Ability of agents to make choices free from certain kinds of constraints

Free will is the ability to choose between different possible courses of action unimpeded.

An epiphenomenon is a secondary phenomenon that occurs alongside or in parallel to a primary phenomenon. The word has two senses: one that connotes known causation and one that connotes absence of causation or reservation of judgment about it.

Mind–body dualism Philosophical theory that mental phenomena are non-physical and that matter exists independently of mind

Mind–body dualism, or mind–body duality, is a view in the philosophy of mind that mental phenomena are, in some respects, 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, and between subject and object, and is contrasted with other positions, such as physicalism and enactivism, in the mind–body problem.

Incompatibilism view that a deterministic universe is completely at odds with the notion that persons have a free will; that there is a dichotomy between determinism and free will where philosophers must choose one or the other

Incompatibilism is the view that a deterministic universe is completely at odds with the notion that persons have a free will; that there is a dichotomy between determinism and free will where philosophers must choose one or the other. This view is pursued in at least three ways: libertarians deny that the universe is deterministic, the hard determinists deny that any free will exists, and pessimistic incompatibilists deny both that the universe is determined and that free will exists.

In the philosophy of mind, emergentmaterialism is a theory which asserts that the mind is an irreducible existent in some sense, albeit not in the sense of being an ontological simple, and that the study of mental phenomena is independent of other sciences. It primarily maintains that the human mind's evolution is a product of material nature and that it cannot exist without material basis.

Libertarianism (metaphysics)

Libertarianism is one of the main philosophical positions related to the problems of free will and determinism, which are part of the larger domain of metaphysics. In particular, libertarianism, which is an incompatibilist position, argues that free will is logically incompatible with a deterministic universe and that agents have free will, and that, therefore, determinism is false. One of the first clear formulations of libertarianism is found in John Duns Scotus; in theological context metaphysical libertarianism was notably defended by Jesuit authors like Luis de Molina and Francisco Suárez against rather compatibilist Thomist Báñezianism. Other important metaphysical libertarians in the early modern period were René Descartes, George Berkeley, Immanuel Kant, and Thomas Reid. Roderick Chisholm was a prominent defender of libertarianism in the 20th century, and contemporary libertarians include Robert Kane, Peter van Inwagen and Robert Nozick.

In philosophy, emergentism is the belief in emergence, particularly as it involves consciousness and the philosophy of mind, and as it contrasts with reductionism. 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. Emergent properties are not identical with, reducible to, or deducible from the other properties. The different ways in which this independence requirement can be satisfied lead to variant types of emergence.

Benjamin Libet American academic

Benjamin Libet was a pioneering scientist in the field of human consciousness. Libet was a researcher in the physiology department of the University of California, San Francisco. In 2003, he was the first recipient of the Virtual Nobel Prize in Psychology from the University of Klagenfurt, "for his pioneering achievements in the experimental investigation of consciousness, initiation of action, and free will".

Property dualism philosophical theory (there is only 1 kind of substance in reality (matter),but that substance has 2 types of properties, material and mental);view that non-physical, mental properties (beliefs,desires,emotions) inhere in physical substances (brains)

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 inhere in or supervene upon certain physical substances. As a doctrine, 'property dualism' is epistemic, as distinct from ontic.

Jaegwon Kim is a Korean-American philosopher who is now an emeritus professor at Brown University, but who also taught at several other leading American universities. 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 or at the time of the event. On this view, mental and bodily phenomena are independent but yet inseparable, like two sides of a coin.

Multiple realizability, in the philosophy of mind, is the thesis that the same mental property, state, or event can be implemented by different physical properties, states, or events. The idea has its roots in the late 1960s and early 1970s when a number of philosophers, most prominently Hilary Putnam and Jerry Fodor (1975), put it forth as an argument against reductionist accounts of the relation between mental and physical kinds. In short, a theory of mind that includes multiple realizability allows for the existence of strong AI. The original targets of these arguments were the type-identity theory and eliminative materialism. The same arguments from multiple realizability were also used to defend many versions of functionalism, especially Machine state functionalism.

Type physicalism in the philosophy of mind, a physicalist theory asserting that mental events can be grouped into types, and can then be correlated with types of physical events in the brain

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.

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.

Mind–body problem open question in philosophy of how abstract minds interact with physical bodies

The mind–body problem is a philosophical problem concerning the relationship between thought and consciousness in the human mind, and the brain as part of the physical body. It is distinct from the question of how mind and body function chemically and physiologically since that question presupposes an interactionist account of mind-body relations. This question arises when mind and body are considered as distinct, based on the premise that the mind and the body are fundamentally different in nature.

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. It is one type of dualism, traditionally a type of substance dualism though more recently also sometimes a form of property dualism.

Peter Ulric Tse is an American cognitive neuroscientist in the Department of Psychological and Brain Sciences, Dartmouth College. He directs the NSF EPSCoR Attention Consortium. He was awarded a Guggenheim Fellowship in 2014.


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  8. Benjamin Libet; Anthony Freeman; Keith Sutherland (2000). "Editors' introduction: The volitional brain". The Volitional Brain: Towards a Neuroscience of Free Will. Academic. pp. ixxxii. ISBN   9780907845119.
  9. > FT Hong (2005). Vladimir B. Bajić; Tin Wee Tan (eds.). Information Processing and Living Systems. Imperial College Press. p. 388. ISBN   9781860946882. The origination of free will is an illusion from the third-person perspective. However, it is a reality from the first-person perspective...
  10. > Thomas Nagel (2012). "Chapter 4: Cognition". Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False. Oxford University Press. p. 71. ISBN   9780199919758. [Higher-level cognitive capacities] cannot be understood through physical science alone, and..their existence cannot be explained by a version of evolutionary theory that is physically reductive.
  11. U Mohrhoff (2000). "The physics of interactionism". In Benjamin Libet; Anthony Freeman; Keith Sutherland (eds.). The Volitional Brain: Towards a Neuroscience of Free Will. Academic. p. 166. ISBN   9780907845119. But the laws of physics presuppose causal closure...Hence it follows that the behaviour of matter in the presence of a causally efficacious non-material mind cannot be fully governed by those laws.
  12. David Hodgson (2012). "Chapter 7: Science and determinism". Rationality + Consciousness = Free Will. Oxford University Press. ISBN   9780199845309. Hodgson relies upon the free will theorem 1, 2 of scientists John Conway and Simon Kochen based upon the role of the observer in quantum mechanics, which supports the view that "belief in determinism may thus come to be seen as notably unscientific." (p. 121)
  13. Stewart Goetz; Charles Taliaferro (2008). "Strict naturalism, purposeful explanation, and freedom". Naturalism (Intervensions) (Paperback ed.). Eerdmans. p. 26. ISBN   978-0802807687.
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