Dualism
Dualism is a family of views proposing a fundamental division into two separate principles or kinds. It typically emphasizes a sharp distinction between independent or antagonistic sides, but in a broader sense, it also includes theories in which the two sides are correlated or complementary. Dualism contrasts with monism, which rejects any fundamental division, and with forms of pluralism that posit more than two basic principles.
Dualist views span many domains and disciplines. Mind–body dualism holds that mind and body are fundamentally different. It includes substance dualism, which interprets mind and body as distinct substances able to exist independently, and property dualism, which characterizes them as separate kinds of properties of the same substance. Ethical dualism targets the contrast between good and evil, regarding them as antagonistic forces that govern human conduct and the cosmic order. Platonic dualism divides reality into the intelligible realm of timeless Forms and the sensory realm of mutable matter, with similarities to the distinction between abstract and concrete objects in the contemporary discourse. Epistemological dualism holds that the object of perception is different from the real object, positing an essential gap between experience and reality. Dualist views also include the Chinese doctrine of yin and yang, conceiving reality as an interplay of two correlated forces, theological dualisms that distinguish God from the world, and the nature–culture divide contrasting the innate state of nature with human practices and institutions. Other dualisms are found in value theory, legal theory, physics, and indigenous belief systems. Critics of dualist thought argue that it ignores continuities, oversimplifies reality, creates pseudoproblems, or introduces evaluative biases.
Dualist thought has its roots in antiquity as a key theme of various religious traditions, such as Zoroastrianism, Jainism, the yinyang school, Samkhya, Gnosticism, and Manichaeism. Abrahamic religions were generally suspicious of dualism, while competing schools of thought along the monism-dualism spectrum emerged in medieval India. Mind–body substance dualism became a central topic in early modern Western philosophy following the works of René Descartes. It was largely replaced by materialist monism in the course of the 20th century.
Definition and related terms
Dualism is a family of views that analyze a domain or phenomenon by proposing a fundamental division into two principles or aspects. Dualist theories differ from each other by the type of division and principles they posit. For example, mind–body dualism argues for a basic contrast between mind and body as distinct substances or properties to explain the fundamental makeup of the world and human experience. Dualists maintain that the two principles are independent and cannot be reduced to one another. They typically emphasize contrast and separation, and some characterize the relationship between the two sides as an antagonistic conflict between opposing forces, such as the clash between good and evil in ethical dualism. In a broad sense, dualism also includes views where the two sides are correlated or complementary rather than opposed.Dualist theories also vary in their scope of analysis and the domain they seek to explain, with some focusing on reality at large while others target specific areas. For instance, the scope of dualism in international law is limited to legal theory about the relation between international and domestic law. Dualism is a widely used theoretical approach found in many fields, including philosophy of mind, metaphysics, theology, mythology, science, ethics, and political theory.
Dualism contrasts with monism, which rejects any fundamental division. Monists argue that the domain in question is unified, meaning that all apparent distinctions ultimately arise from a single principle. For example, materialist monism rejects the mind–body division, arguing that mind is not an independent principle since everything is fundamentally matter. Because dualism posits two basic principles, it is a form of pluralism. It contrasts with other pluralistic theories that posit more than two basic principles. For instance, the metaphysical pluralism of the pre-Socratic philosopher Empedocles holds that everything is composed of four root elements: fire, earth, air, and water. Since monism, dualism, and other forms of pluralism analyze a domain in terms of one or more principles, they differ from nihilist or eliminativist theories, which deny the reality of the analyzed phenomena.
Dualism is closely related to duality, dichotomy, and binary opposition. Although these terms overlap and are sometimes used interchangeably, they are not identical and carry distinct nuances. Duality is the quality of being twofold or having two distinct parts. Dualities are often associated with correlated parts, whereas dualisms tend to emphasize the opposition between the two sides. A dichotomy is a division or splitting of something into two contrasting or mutually exclusive parts. Such divisions may or may not have a deeper philosophical significance and need not reflect reality, as in a false dichotomy. A binary opposition is a relation between two terms with opposite meanings. The concept plays a central role in structuralist and post-structuralist theories as the idea that cultural and linguistic systems generate and stabilize meaning through oppositional pairs.
The term dualism comes from the Latin word dualis, meaning. It entered the English language as the term dual in the 16th century. In the late 18th century, the abstract noun dualism was formed with the suffix -ism to denote a theory. The first known use was in 1794 by the satirist and scholar Thomas James Mathias.
Mind–body dualism
Mind–body dualism is the view that mind and body are fundamentally different. It holds that mental phenomena, such as thoughts, emotions, volitions, and consciousness, exist as nonphysical entities in addition to physical entities, such as the brain. A key motivation for this distinction is that physical and mental phenomena seem to have different characteristics. Physical objects encountered in everyday life have size, shape, color, weight, and spatial location. They appear objective, can be perceived through the senses, and can be measured using scientific instruments. Mental phenomena, by contrast, appear private and subjective without a clearly identifiable size, color, or spatial location. The mind–body problem is the challenge of explaining the relation between the two, and dualism is one approach to addressing it. Dualists debate the exact nature of body, mind, and their relation, giving rise to a variety of dualist theories.Variations
Substance dualism asserts that body and mind are distinct substances. In metaphysics, a substance is a fundamental entity with independent existence. Accordingly, substance dualists typically assert that body and mind can each exist on their own, at least in principle. This view leaves open the possibility that the mind or soul may persist after bodily death, potentially in an afterlife. An influential substance dualism was formulated by René Descartes, who argued that bodies are extended things, while minds are thinking things.Substance dualism contrasts with property dualism, which asserts that there are only physical substances, which have both physical and mental properties. In metaphysics, properties are features of entities, describing their characteristics or what those entities are like. Accordingly, the mind is characterized as an aspect of a substance but not as something that can exist on its own. The dualistic outlook of this view rests on the idea that mental properties cannot be reduced to physical descriptions, such as brain states, meaning that a scientific account of the world based only on physical attributes would be incomplete.
Various dualist theories in Indian philosophy resemble Western mind–body dualism but differ in some key aspects. In Samkhya philosophy, the foundational division is between purusha and prakriti. A purusha is an individual self, understood as a pure, contentless consciousnessan inactive and unchanging observer. Prakriti is materiality, encompassing not only ordinary material objects but also contents of consciousness, including cognitions and emotions. Similar dualisms with some variations are also found in the schools of Yoga, Vaisheshika, and Nyaya.
Problem of interaction
A central topic in mind–body dualism is the problem of interaction: explaining whether or in which way mind and body causally influence each other. According to interactionism, this influence goes both ways, with the senses transmitting causal influences from body to mind and volitions translating mental plans into actions. For instance, a bodily injury can produce a mental pain experience, and a mental fear can cause the body to flee. A difficulty for this view is the principle of conservation of energy, according to which the total energy of a closed physical system can neither increase nor decrease, making it unclear how the mind can influence without altering the energy balance. Another objection is based on the problem of overdetermination, according to which physical causes already explain all physical effects and do not require additional mental causes.Epiphenomenalism, a different approach, holds that the interaction is only one-way: bodily phenomena cause mental phenomena, but mental phenomena have no effects. Accordingly, the mind is characterized as an epiphenomenon: a byproduct of brain processes without causal influence of its own. One criticism of this view focuses on the counterintuitive implication that mental states like fear do not influence behavior. The evolutionary challenge, another objection, questions how the mind could have developed at all if it is irrelevant to survival or reproduction.
Parallelism proposes that no interaction between mind and body takes place. It maintains that a mental cause-effect chain and a physical cause-effect chain run in parallel without influencing each other. A central problem for this view is explaining how or why the two separate realms are synchronized.