Ontological dualism

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As ontological dualism are philosophical positions referred to assume that everything is ( ontology ) in two mutually exclusive types of entities or substances decays ( dualism ), and describe whether and interactions between these modes are possible as shown. In the western philosophical tradition, material and immaterial (“spiritual”) entities are juxtaposed. Ontological dualism is historically and thematically closely intertwined with metaphysical dualism; The starting point is often the effort to find a solution to the mind-body problem .

René Descartes' illustration of dualism: stimuli are passed on from the sense organs, reach the epiphysis in the brain and there act on the immaterial mind

Ontological dualism

Diversity of ontological dualisms

Three substance dualisms; the arrows describe the path of causal interaction (red circles represent mental states, blue circles represent physical states)

Even if the classical ontological dualism distinguishes between material and immaterial, especially spiritual , entities, the immateriality of other phenomena is also repeatedly asserted, such as aesthetic and moral properties, numbers and propositions . Dualists are considered candidates for immaterial entities as all those phenomena that cannot be explained by the natural sciences and thus resist reduction . However, irreducibility cannot be taken as proof of immateriality, since there are also attempts to formulate non-reductive materialisms .

Dualisms differ not only in the answer to the question of which entities should be considered immaterial. There are also various ways of describing the immaterial entities ontologically . On the one hand, a dualism of substance is possible that is based on material and immaterial objects . On the other hand, however, a dualism of properties can also be represented which is monistic with regard to objects. Characteristic dualistic positions are very popular in the current philosophy of mind , while classical substance dualisms are rarely found there.

Substance dualisms

Interactionist dualism

Illustration by Descartes: An irritation on the foot is conducted via the nerves into the brain, where it interacts with the mind and thus creates an experience of pain.

The interactionist dualism is considered a classic version of substance dualism and was represented by René Descartes , for example . According to the interactionist dualism, there are material and immaterial entities that interact causally with each other. When a person is tickled, for example, the stimuli are registered by the material body and passed on to the brain . At some point the material processes then act on the immaterial mind and create a tickling experience. Conversely, mental states, such as thoughts or emotions , trigger physical processes. Descartes suspected that the epiphysis , a neural structure that is characterized by the fact that it occurs only once in the brain, is the place of interaction .

Again and again it was objected to the interactionist dualism that it was empirically implausible, since the neurosciences could not find such a place of interaction between mind and brain. Rather, a neural cause could be found for every neural process, so that there would be no need for the intervention of the mind anywhere . This objection to interactionist dualism can also be understood more generally: If such a position were true, then the idea of ​​the causal closure of the material world would have to be abandoned. This means that there is a purely physical cause for every physical event . An interactionist dualist must deny this, since he takes the view that some physical events are only caused by immaterial events. Now, however, it is argued by non-dualists that the causal closeness of the world is not only a plausible assumption, but also very well proven empirically.

Karl Popper and John Eccles , the best-known exponents of interactionist dualism in the 20th century, tried to avoid this objection by shifting the interaction between mind and brain to a subatomic level.

Above all, Popper argued against the closed nature of the physical world with his three worlds doctrine , which would shed new light on the body-mind problem. According to this theory, objects of world 3 (mental objects) are abstract, but nonetheless real and even particularly powerful tools for changing world 1 (physical world). The objects of world 3 , however, could not be effective of their own accord; they are dependent on being received and "realized" by world 2 (human consciousness). In this respect, they are similar to viruses, for example, which do not have their own metabolism and therefore cannot become active on their own, but can still be the cause of specific effects (viral diseases). Against the objection that we do not know how the action of mind on physical objects is possible, Popper argued that we actually do not even know exactly how it is possible for physical objects to affect other physical objects. It is just an (evident) fact that this is possible.

Non-interactionist dualism

A non-interactionist variant of substance dualism was developed by Gottfried Wilhelm Leibniz , who claimed that mind and body do not interact in any way. However, this theory, psychophysical parallelism , has the problem of having to explain how the connections between mental and material states come about. After all, the mental (or, better, mental) state of thirst usually results in the physical event of drinking, which, however, seems inexplicable if the mind cannot influence the body. Leibniz tried to refute this objection with an analogy . He explained that the mind and body behave like two parallel clocks. The events are perfectly coordinated, even if there is no causal interaction. But now one can ask why there is such a parallelism. Leibniz declared that this was an institution of God .

A related metaphysical position, occasionalism , comes from Nicolas Malebranche . According to occassionalism, the mind and body have no causal influence on each other. However, the changes in body and spirit are registered by God, who triggers the corresponding mental or physical processes. The causality, which apparently connects the spiritual and material events, is solely attributed to the fact that the person repeatedly observes the occurrence of one event as a result of the other and draws the wrong conclusion of a causal connection. This - according to the theory - is by no means proof of causality. Rather, every event is a discrete, self-contained process; the world in the course of time consists of a multitude of ever new worlds, each of which is newly created by God ex nihilo - out of nothing. In this way, occassionalists try to solve the problem of mind-matter interaction - there is no causal interaction, God alone is the cause of all - spiritual as well as material - events. Occasionalism, like psychophysical parallelism, is rarely represented today.

Another variant of dualism is epiphenomenalism , which was represented by Thomas Henry Huxley . Epiphenomenalists believe that physical states can causally affect mental ones, but mental states cannot affect physical ones. Such a position is compatible with the idea of ​​the causal closure of the world and can nevertheless explain how the connections between mind and body come about. These characteristics have led to the fact that restricted variants of epiphenomenalism are still represented today. However, these positions are mostly property-dualistic epiphenomenalisms. So they claim the existence of immaterial, causally ineffective properties and not the existence of such objects or substances. Numerous objections have also been raised against epiphenomenalism. It is doubtful, for example, how one can even know about mental states when they have no effect. It has also been argued again and again that the idea of ​​causally completely ineffective entities is not at all coherent .

Property dualisms

Property dualistic positions are more popular than substance dualisms in today's philosophical debate. Qualitative dualists argue that a person is not composed of two substances (mind and body). Rather, they claim that there is only one object (person), but that it has physical and mental properties. Qualia , i.e. the subjective content of experience, are often viewed by property dualists as non-material properties, since the ability to reduce them to physical or physical states remains doubtful.

In today's philosophy of mind , the dualistic arguments of David Chalmers and Frank Cameron Jackson are the main debates, but the historical roots of this position go back much further. Even Baruch de Spinoza neutral monism came from a substance has the material and spiritual qualities. In the 19th century an analogue position was made popular by Ernst Haeckel , for example .

Property dualism, however, has to struggle with similar problems as substance dualism, since it too has to explain the causal effectiveness of mental states, the mental causation . Should the mental properties have a causal influence on the material world, then the property dualist seems to have to deny the causal closeness of the world, which, as described above, leads to problems. If, on the other hand, the property dualist renounces the causal effectiveness of mental properties, he must represent a form of epiphenomenalism . However, not all trait dualists accept to face such a dilemma . Some argue that the world is causally closed, that there is a physical cause for every physical event, and that mental properties are nevertheless causally effective. Such philosophers must explain that some events are caused by physical and mental properties at the same time .

Arguments for dualism

Conceivability arguments

René Descartes in a portrait by Frans Hals , 1648

The classic argument for dualism was formulated by Descartes in the Meditationes de prima philosophia . Descartes argued that he could clearly imagine that mind and body were separate from one another. According to Descartes, the fact that this is conceivable also means that it is possible in principle . However, if it is only possible in principle for the mind and the body to exist separately from one another, they cannot be identical. So there has to be an immaterial mind. Such an argument must, among other things, put up with the question of why the imaginability of the separation of mind and body should prove its possibility. Descartes explained that the structure of the world is such that everything that can be clearly and clearly imagined can also be arranged accordingly by God , i.e. is possible. However, it is not clear whether such an argument can be successful. Not only does it presuppose the existence of God (cf. natural theology ), it is also not clear why a theist has to accept the assumption that God can arrange everything that can be clearly imagined.

In spite of these problems, arguments of imaginability continue to have a certain popularity, partly because they were formulated in a new way by Saul Kripke . Kripke's goal is to show that imaginability implies possibility, which would make Descartes' argument plausible again. Such an implication relationship seems unlikely at first, since relationships seem conceivable that are not possible. So it might seem conceivable that water and H 2 O are not identical. One can, for example, design the thought experiment that the early chemists did not come across H 2 O but rather another compound XYZ when studying water . This seems to be imagining a situation where water and H 2 O are not the same. However, this situation is obviously not possible because water and H 2 O are identical. And if two phenomena A and B are identical, then A can never occur without B or B without A.

Kripke now claims that the thought experiment does not lead to the idea of ​​a situation in which water is not H 2 O. Rather, imagine a case with the thought experiment in which a substance that has the same macro-properties as water (liquid, transparent, odorless, boiling at 100 ° C etc.) is not H 2 O. However, this substance is not water, since water is identical to H 2 O, but a different substance similar to water. Kripke considers this result to be generalizable: whenever a situation seems imaginable but not possible, this impression can be explained away by an analysis of the reference relationships. If Kripke's diagnosis is correct, there is no case in which X is imaginable but not possible. So if it is conceivable that the mind appears without the body, then this is also possible and then they cannot be identical. However, objections to Kripke's argument are also possible. For example, one can deny that it is even conceivable that the mind appears without the body.

Quality-based arguments

Many contemporary arguments for ontological dualism are based on the phenomenon of qualia . Qualia is the name given to the subjective experience of mental states, for example the experience of blue that is associated with the perception of a blue object. Now it is often argued that the Qualia intangible qualities are, because they are not on physical - characteristics - such as neural reduce left. Materialists counter this with various arguments. While some rely on the reducibility of the qualia, non-reductive materialists explain that the qualia can be material but irreducible properties.

Dualists have further developed the qualification arguments in various ways. A popular version comes from the Australian philosopher Frank Cameron Jackson , who formulated a thought experiment with a super scientist named "Mary": Mary is a physiologist who specializes in color vision, has been trapped in a black and white laboratory since she was born and has never seen colors . She knows all the physical facts about seeing color, but she doesn't know what colors look like. Jackson's argument against materialism is now quite brief: Mary knows all the physical facts about seeing colors. Still, she doesn't know all the facts about seeing colors. So there are non-physical facts, so the dualism is true. Jackson has now distanced himself from this argument.

See also


Web links

Individual evidence

  1. Karl Popper , John Carew Eccles : The I and its brain. 8th edition. Piper, Munich et al. 2002, ISBN 3-492-21096-1 .
  2. In F. Beck, J. Eccles: Quantum aspects of brain activity and the role of consciousness. In: Proceedings of the National Academy of Sciences of the USA. 89, 1992, pp. 11357-11361, it is postulated that the will becomes effective on the quantum mechanical level by increasing the probability of exocytosis .
  3. Gottfried Wilhelm Leibniz : Monadology. lat. 1737, French. 1840.
  4. Nicolas Malebranche : From the exploration of the truth. 1674/75
  5. ^ A b c Frank Cameron Jackson : Epiphenomenal Qualia. In: Philosophical Quartaly. 1982.
  6. ^ Peter Bieri : Trying out Epiphenomenalism. In: Knowledge. 1992.
  7. David Chalmers : The conscious Mind. Oxford University Press, Oxford 1997, ISBN 0-19-511789-1 .
  8. Ernst Haeckel : The world riddle. 1899.
  9. ^ Saul Kripke : Naming and Necessity . Blackwell Pub., Oxford 1981, ISBN 0-631-12801-8 .
  10. Frank Jackson: "Most contemporary philosophers given a choice between going with science and going with intuitions, go with science. Although I once dissented from the majority, I have capitulated and now see the interesting issue as being where the arguments from the intuitions against physicalism - the arguments that seem so compelling - go wrong. " Quoting from "Mind and Illusion" in Anthony O'Hear (Ed.): "Minds and Persons", Cambridge University Press, 2003, pp. 251-271. Online version on David Chalmers' website consc.net ( Memento from June 27, 2016 in the Internet Archive )
This version was added to the list of articles worth reading on March 29, 2006 .