Reductionism is any of several related
philosophical ideas regarding the associations between
phenomena
A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried W ...
which can be described in terms of other simpler or more fundamental phenomena.
It is also described as an intellectual and philosophical position that interprets a complex system as the sum of its parts.
Definitions
''
The Oxford Companion to Philosophy
''The Oxford Companion to Philosophy'' (1995; second edition 2005) is a reference work in philosophy edited by the philosopher Ted Honderich and published by Oxford University Press
Oxford University Press (OUP) is the university press of t ...
'' suggests that reductionism is "one of the most used and abused terms in the philosophical lexicon" and suggests a three-part division:
# Ontological reductionism: a belief that the whole of reality consists of a minimal number of parts.
# Methodological reductionism: the scientific attempt to provide an explanation in terms of ever-smaller entities.
# Theory reductionism: the suggestion that a newer theory does not replace or absorb an older one, but reduces it to more basic terms. Theory reduction itself is divisible into three parts: translation, derivation, and explanation.
Reductionism can be applied to any
phenomenon
A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried W ...
, including
objects
Object may refer to:
General meanings
* Object (philosophy), a thing, being, or concept
** Object (abstract), an object which does not exist at any particular time or place
** Physical object, an identifiable collection of matter
* Goal, an ...
, problems,
explanation
An explanation is a set of Statement (logic), statements usually constructed to description, describe a set of facts which clarifies the causality, causes, wiktionary:context, context, and Logical consequence, consequences of those facts. It may ...
s,
theories
A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be s ...
, and meanings.
For the sciences, application of methodological reductionism attempts explanation of entire systems in terms of their individual, constituent parts and their interactions. For example, the temperature of a gas is reduced to nothing beyond the average kinetic energy of its molecules in motion.
Thomas Nagel
Thomas Nagel (; born July 4, 1937) is an American philosopher. He is the University Professor of Philosophy and Law Emeritus at New York University, where he taught from 1980 to 2016. His main areas of philosophical interest are legal philosophy, ...
and others speak of 'psychophysical reductionism' (the attempted reduction of psychological phenomena to physics and chemistry), and 'physico-chemical reductionism' (the attempted reduction of biology to physics and chemistry).
In a very simplified and sometimes contested form, reductionism is said to imply that a system is nothing but the sum of its parts.
However, a more nuanced opinion is that a system is composed entirely of its parts, but the system will have features that none of the parts have (which, in essence is the basis of
emergentism
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 int ...
).
"The point of mechanistic explanations is usually showing how the higher level features arise from the parts."
Other definitions are used by other authors. For example, what
John Polkinghorne
John Charlton Polkinghorne (16 October 1930 – 9 March 2021) was an English theoretical physicist, theologian, and Anglican priest. A prominent and leading voice explaining the relationship between science and religion, he was professor of ma ...
terms 'conceptual' or 'epistemological' reductionism
is the definition provided by
Simon Blackburn and by
Jaegwon Kim:
that form of reductionism which concerns a program of replacing the facts or entities involved in one type of discourse with other facts or entities from another type, thereby providing a relationship between them. Richard Jones distinguishes ontological and epistemological reductionism, arguing that many ontological and epistemological reductionists affirm the need for different concepts for different degrees of complexity while affirming a reduction of theories.
The idea of reductionism can be expressed by "levels" of explanation, with higher levels reducible if need be to lower levels. This use of levels of understanding in part expresses our human limitations in remembering detail. However, "most philosophers would insist that our role in conceptualizing reality
ur need for a hierarchy of "levels" of understandingdoes not change the fact that different levels of organization in reality do have different 'properties'."
Reductionism should be distinguished from
eliminationism
Eliminationism is the belief that one's political opponents are, in the words of Oklahoma City University School of Law professor Phyllis E. Bernard, "a cancer on the body politic that must be excised—either by separation from the public at la ...
: reductionists do not deny the existence of phenomena, but explain them in terms of another reality; eliminationists deny the existence of the phenomena themselves. For example, eliminationists deny the existence of life by their explanation in terms of physical and chemical processes.
Reductionism does not preclude the existence of what might be termed
emergent phenomena
In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole.
Emergence ...
, but it does imply the ability to understand those phenomena completely in terms of the processes from which they are composed. This reductionist understanding is very different from ontological or strong
emergentism
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 int ...
, which intends that what emerges in "emergence" is more than the sum of the processes from which it emerges, respectively either in the ontological sense or in the epistemological sense. Some physicists, however, claim that reductionism and emergentism are complementary: both are needed to explain natural processes.
Types
Most philosophers delineate three types of reductionism and anti-reductionism.
Ontological reductionism
Ontological reductionism is the belief that reality is composed of a minimum number of kinds of entities or substances.
This claim is usually
metaphysical
Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
, and is most commonly a form of
monism
Monism attributes oneness or singleness (Greek: μόνος) to a concept e.g., existence. Various kinds of monism can be distinguished:
* Priority monism states that all existing things go back to a source that is distinct from them; e.g., i ...
, in effect claiming that all objects, properties, and events are reducible to a single substance. (A
dualist
Dualism most commonly refers to:
* Mind–body dualism, a philosophical view which holds that mental phenomena are, at least in certain respects, not physical phenomena, or that the mind and the body are distinct and separable from one another
** ...
who is an ontological reductionist would believe that everything is reducible to two substances—as one possible example, a dualist might claim that reality is composed of "
matter
In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...
" and "
spirit
Spirit or spirits may refer to:
Liquor and other volatile liquids
* Spirits, a.k.a. liquor, distilled alcoholic drinks
* Spirit or tincture, an extract of plant or animal material dissolved in ethanol
* Volatile (especially flammable) liquids, ...
".)
Richard Jones divides ontological reductionism into two: the reductionism of substances (e.g., the reduction of mind to matter) and the reduction of the number of structures operating in nature (e.g., the reduction of one physical force to another). This permits scientists and philosophers to affirm the former while being anti-reductionists regarding the latter.
Nancey Murphy
Nancey Murphy (born 12 June 1951) is an American philosopher and theologian who is Professor of Christian Philosophy at Fuller Theological Seminary, Pasadena, CA. She received the B.A. from Creighton University (philosophy and psychology) in 1973 ...
has claimed that there are two species of ontological reductionism: one that claims that wholes are nothing more than their parts; and atomist reductionism, claiming that wholes are not "really real". She admits that the phrase "really real" is apparently senseless but she has tried to explicate the supposed difference between the two.
Ontological reductionism denies the idea of ontological
emergence
In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole.
Emergence ...
, and claims that emergence is an
epistemological
Epistemology (; ), or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics.
Episte ...
phenomenon that only exists through analysis or description of a system, and does not exist fundamentally.
Ontological reductionism takes two forms: token ontological reductionism and type ontological reductionism.
Token ontological reductionism is the idea that every item that exists is a sum item. For perceivable items, it affirms that every perceivable item is a sum of items with a lesser degree of complexity. Token ontological reduction of biological things to chemical things is generally accepted.
Type ontological reductionism is the idea that every type of item is a sum type of item, and that every perceivable type of item is a sum of types of items with a lesser degree of complexity. Type ontological reduction of biological things to chemical things is often rejected.
Michael Ruse
Michael Ruse (born 21 June 1940) is a British-born Canadian philosopher of science who specializes in the philosophy of biology and works on the relationship between science and religion, the creation–evolution controversy, and the demarcatio ...
has criticized ontological reductionism as an improper argument against
vitalism
Vitalism is a belief that starts from the premise that "living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things." Wher ...
.
Methodological reductionism
Methodological reductionism is the position that the best scientific strategy is to attempt to reduce explanations to the smallest possible entities.
In a biological context, this means attempting to explain all biological phenomena in terms of their underlying biochemical and molecular processes. Claim of efficacy is demonstrated that the gene—unit of classical heredity—is the deoxyribonucleic acid (DNA), a macro-molecule.
Theory reductionism
Theory reduction is the process by which a more general theory absorbs a special theory.
For example, both
Kepler's laws of the motion of the
planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
s and
Galileo
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He was ...
's theories of motion formulated for terrestrial objects are reducible to Newtonian theories of mechanics because all the explanatory power of the former are contained within the latter. Furthermore, the reduction is considered beneficial because
Newtonian mechanics
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows:
# A body remains at rest, or in motion ...
is a more general theory—that is, it explains more events than Galileo's or Kepler's. Besides scientific theories, theory reduction more generally can be the process by which one explanation subsumes another.
In science
Reductionist thinking and methods form the basis for many of the well-developed topics of modern
science
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science may be as old as the human species, and some of the earliest archeological evidence for ...
, including much of
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
,
chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
and
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
.
Classical mechanics
Classical mechanics is a physical theory describing the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars, and galaxies. For objects governed by classical ...
in particular is seen as a reductionist framework. For instance, we understand the solar system in terms of its components (the sun and the planets) and their interactions.
Statistical mechanics
In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic be ...
can be considered as a reconciliation of
macroscopic thermodynamic laws
The laws of thermodynamics are a set of scientific laws which define a group of physical quantities, such as temperature, energy, and entropy, that characterize thermodynamic systems in thermodynamic equilibrium. The laws also use various paramet ...
with the reductionist method of explaining macroscopic properties in terms of
microscopic
The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens (optics), lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded a ...
components, although it has been argued that reduction in physics 'never goes all the way in practice'.
In science, reductionism implies that certain topics of study are based on areas that study smaller spatial scales or organizational units. While it is commonly accepted that the foundations of
chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
are based in
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
, and
molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
is based on chemistry, similar statements become controversial when one considers less rigorously defined intellectual pursuits. For example, claims that
sociology
Sociology is a social science that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of Empirical ...
is based on
psychology
Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries betwe ...
, or that
economics
Economics () is the social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services.
Economics focuses on the behaviour and intera ...
is based on
sociology
Sociology is a social science that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of Empirical ...
and
psychology
Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries betwe ...
would be met with reservations. These claims are difficult to substantiate even though there are obvious associations between these topics (for instance, most would agree that
psychology
Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries betwe ...
can affect and inform
economics
Economics () is the social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services.
Economics focuses on the behaviour and intera ...
). The limit of reductionism's usefulness stems from
emergent properties
In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole.
Emergence ...
of
complex systems
A complex system is a system composed of many components which may interact with each other. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communication s ...
, which are more common at certain levels of organization. For example, certain aspects of
evolutionary psychology
Evolutionary psychology is a theoretical approach in psychology that examines cognition and behavior from a modern evolutionary perspective. It seeks to identify human psychological adaptations with regards to the ancestral problems they evolv ...
and
sociobiology are rejected by some who claim that complex systems are inherently irreducible and that a
holistic method is needed to understand them.
Some strong reductionists believe that the behavioral sciences should become "genuine" scientific disciplines based on genetic biology, and on the systematic study of culture (see Richard Dawkins's concept of
memes). In his book ''
The Blind Watchmaker
''The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe without Design'' is a 1986 book by Richard Dawkins, in which the author presents an explanation of, and argument for, the theory of evolution by means of natural selecti ...
'',
Dawkins Dawkins is an English surname. Notable people with the surname include:
* Aubrey Dawkins (born 1995), American basketball player
* Ben Dawkins, Australian politician
* Benjamin C. Dawkins Jr. (1911–1984), US District Judge in Louisiana
* B ...
introduced the term "hierarchical reductionism" to describe the opinion that complex systems can be described with a hierarchy of organizations, each of which is only described in terms of objects one level down in the hierarchy. He provides the example of a computer, which using hierarchical reductionism is explained in terms of the operation of
hard drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
s, processors, and memory, but not on the level of
logic gates
A logic gate is an idealized or physical device implementing a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate ...
, or on the even simpler level of electrons in a
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
medium.
Others argue that inappropriate use of reductionism limits our understanding of complex systems. In particular, ecologist
Robert Ulanowicz
Robert Edward Ulanowicz ( ) is an American theoretical ecologist and philosopher of Polish descent who in his search for a ''unified theory of ecology'' has formulated a paradigm he calls ''Process Ecology''. He was born September 17, 1943 in Bal ...
says that science must develop techniques to study ways in which larger scales of organization influence smaller ones, and also ways in which feedback loops create structure at a given level, independently of details at a lower level of organization. He advocates (and uses)
information theory
Information theory is the scientific study of the quantification (science), quantification, computer data storage, storage, and telecommunication, communication of information. The field was originally established by the works of Harry Nyquist a ...
as a framework to study
propensities in natural systems. Ulanowicz attributes these criticisms of reductionism to the philosopher
Karl Popper
Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian-British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the cl ...
and biologist
Robert Rosen.
Stuart Kauffman has argued that
complex systems
A complex system is a system composed of many components which may interact with each other. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communication s ...
theory and phenomena such as
emergence
In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole.
Emergence ...
pose limits to reductionism. Emergence is especially relevant when systems exhibit
historicity. Emergence is strongly related to
nonlinearity. The limits of the application of reductionism are claimed to be especially evident at levels of organization with greater
complexity
Complexity characterises the behaviour of a system or model whose components interaction, interact in multiple ways and follow local rules, leading to nonlinearity, randomness, collective dynamics, hierarchy, and emergence.
The term is generall ...
, including living
cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
,
[online]
/ref> neural networks
A neural network is a network or circuit of biological neurons, or, in a modern sense, an artificial neural network, composed of artificial neurons or nodes. Thus, a neural network is either a biological neural network, made up of biological ...
, ecosystems, society
A society is a group of individuals involved in persistent social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same political authority and dominant cultural expectations. Socie ...
, and other systems formed from assemblies of large numbers of diverse components linked by multiple feedback loops.
Nobel laureate
The Nobel Prizes ( sv, Nobelpriset, no, Nobelprisen) are awarded annually by the Royal Swedish Academy of Sciences, the Swedish Academy, the Karolinska Institutet, and the Norwegian Nobel Committee to individuals and organizations who make out ...
Philip Warren Anderson
Philip Warren Anderson (December 13, 1923 – March 29, 2020) was an American theoretical physicist and Nobel laureate. Anderson made contributions to the theories of localization, antiferromagnetism, symmetry breaking (including a paper in 19 ...
used the idea that symmetry breaking is an example of an emergent phenomenon in his 1972 ''Science
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science may be as old as the human species, and some of the earliest archeological evidence for ...
'' paper "More is different" to make an argument about the limitations of reductionism. One observation he made was that the sciences can be arranged roughly in a linear hierarchy—particle physics
Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...
, solid state physics
Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the l ...
, chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
, molecular biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...
, cellular biology
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and ...
, physiology
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...
, psychology
Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries betwe ...
, social sciences
Social science is one of the branches of science, devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of soci ...
—in that the elementary entities of one science obeys the principles of the science that precedes it in the hierarchy; yet this does not imply that one science is just an applied version of the science that precedes it. He writes that "At each stage, entirely new laws, concepts and generalizations are necessary, requiring inspiration and creativity to just as great a degree as in the previous one. Psychology is not applied biology nor is biology applied chemistry."
Disciplines such as cybernetics
Cybernetics is a wide-ranging field concerned with circular causality, such as feedback, in regulatory and purposive systems. Cybernetics is named after an example of circular causal feedback, that of steering a ship, where the helmsperson m ...
and systems theory imply non-reductionism, sometimes to the extent of explaining phenomena at a given level of hierarchy in terms of phenomena at a higher level, in a sense, the opposite of reductionism.
In mathematics
In mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
, reductionism can be interpreted as the philosophy that all mathematics can (or ought to) be based on a common foundation, which for modern mathematics is usually axiomatic set theory
Set theory is the branch of mathematical logic that studies Set (mathematics), sets, which can be informally described as collections of objects. Although objects of any kind can be collected into a set, set theory, as a branch of mathematics, ...
. Ernst Zermelo
Ernst Friedrich Ferdinand Zermelo (, ; 27 July 187121 May 1953) was a German logician and mathematician, whose work has major implications for the foundations of mathematics. He is known for his role in developing Zermelo–Fraenkel axiomatic se ...
was one of the major advocates of such an opinion; he also developed much of axiomatic set theory. It has been argued that the generally accepted method of justifying mathematical axioms by their usefulness in common practice can potentially weaken Zermelo's reductionist claim.
Jouko Väänänen has argued for second-order logic as a foundation for mathematics instead of set theory, whereas others have argued for category theory
Category theory is a general theory of mathematical structures and their relations that was introduced by Samuel Eilenberg and Saunders Mac Lane in the middle of the 20th century in their foundational work on algebraic topology. Nowadays, cate ...
as a foundation for certain aspects of mathematics.
The incompleteness theorems of Kurt Gödel
Kurt Friedrich Gödel ( , ; April 28, 1906 – January 14, 1978) was a logician, mathematician, and philosopher. Considered along with Aristotle and Gottlob Frege to be one of the most significant logicians in history, Gödel had an imme ...
, published in 1931, caused doubt about the attainability of an axiomatic foundation for all of mathematics. Any such foundation would have to include axioms powerful enough to describe the arithmetic of the natural numbers (a subset of all mathematics). Yet Gödel proved that, for any ''consistent'' recursively enumerable axiomatic system powerful enough to describe the arithmetic of the natural numbers, there are (model-theoretically) ''true'' propositions about the natural numbers that cannot be proved from the axioms. Such propositions are known as formally undecidable propositions. For example, the continuum hypothesis is undecidable in the Zermelo–Fraenkel set theory
In set theory, Zermelo–Fraenkel set theory, named after mathematicians Ernst Zermelo and Abraham Fraenkel, is an axiomatic system that was proposed in the early twentieth century in order to formulate a theory of sets free of paradoxes such as ...
as shown by Cohen.
In computer science
The role of reduction in computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...
can be thought as a precise and unambiguous mathematical formalization of the philosophical idea of " theory reductionism". In a general sense, a problem (or set) is said to be reducible to another problem (or set), if there is a computable/feasible method to translate the questions of the former into the latter, so that, if one knows how to computably/feasibly solve the latter problem, then one can computably/feasibly solve the former. Thus, the latter can only be at least as "hard
Hard may refer to:
* Hardness, resistance of physical materials to deformation or fracture
* Hard water, water with high mineral content
Arts and entertainment
* ''Hard'' (TV series), a French TV series
* Hard (band), a Hungarian hard rock super ...
" to solve as the former.
Reduction in theoretical computer science
Theoretical computer science (TCS) is a subset of general computer science and mathematics that focuses on mathematical aspects of computer science such as the theory of computation, lambda calculus, and type theory.
It is difficult to circumsc ...
is pervasive in both: the mathematical abstract foundations of computation; and in real-world performance or capability analysis of algorithms. More specifically, reduction is a foundational and central concept, not only in the realm of mathematical logic and abstract computation in computability (or recursive) theory, where it assumes the form of e.g. Turing reduction, but also in the realm of real-world computation in time (or space) complexity analysis of algorithms, where it assumes the form of e.g. polynomial-time reduction
In computational complexity theory, a polynomial-time reduction is a method for solving one problem using another. One shows that if a hypothetical subroutine solving the second problem exists, then the first problem can be solved by transforming ...
.
In religion
Religious reductionism generally attempts to explain religion by explaining it in terms of nonreligious causes. A few examples of reductionistic explanations for the presence of religion are: that religion can be reduced to humanity's conceptions of right and wrong, that religion is fundamentally a primitive attempt at controlling our environments, that religion is a way to explain the existence of a physical world, and that religion confers an enhanced survivability for members of a group and so is reinforced by natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
. Anthropologists Edward Burnett Tylor and James George Frazer
Sir James George Frazer (; 1 January 1854 – 7 May 1941) was a Scottish social anthropologist and folklorist influential in the early stages of the modern studies of mythology and comparative religion.
Personal life
He was born on 1 Janua ...
employed some religious reductionist arguments.
In linguistics
Linguistic reductionism is the idea that everything can be described or explained by a language with a limited number of concepts, and combinations of those concepts. An example is the language Toki Pona
Toki Pona (rendered as ''toki pona'' and often translated as 'the language of good'; ; ) is a philosophical artistic constructed language (philosophical artlang) known for its small vocabulary, simplicity, and ease of acquisition. It was create ...
.
In philosophy
The concept of downward causation In philosophy, downward causation is a causal relationship from higher levels of a system to lower-level parts of that system: for example, mental events acting to cause physical events. The term was originally coined in 1974 by the philosopher and ...
poses an alternative to reductionism within philosophy. This opinion is developed by Peter Bøgh Andersen, Claus Emmeche
Claus Emmeche (born 1956) is a Danish theoretical biologist and philosopher, one of founders of contemporary biosemiotics. He is associate professor at the University of Copenhagen, and is head of the Center for the Philosophy of Nature and Sci ...
, Niels Ole Finnemann, and Peder Voetmann Christiansen, among others. These philosophers explore ways in which one can talk about phenomena at a larger-scale level of organization exerting causal influence on a smaller-scale level, and find that some, but not all proposed types of downward causation are compatible with science. In particular, they find that constraint is one way in which downward causation can operate. The notion of causality as constraint has also been explored as a way to shed light on scientific concepts such as self-organization
Self-organization, also called spontaneous order in the social sciences, is a process where some form of overall order arises from local interactions between parts of an initially disordered system. The process can be spontaneous when suffi ...
, natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
, adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
, and control.
Free will
Philosophers of the Enlightenment
Enlightenment or enlighten may refer to:
Age of Enlightenment
* Age of Enlightenment, period in Western intellectual history from the late 17th to late 18th century, centered in France but also encompassing (alphabetically by country or culture): ...
worked to insulate human free will from reductionism. Descartes separated the material world of mechanical necessity from the world of mental free will. German philosophers introduced the concept of the "noumenal
In philosophy, a noumenon (, ; ; noumena) is a posited object or an event that exists independently of human sense and/or perception. The term ''noumenon'' is generally used in contrast with, or in relation to, the term ''phenomenon'', which ...
" realm that is not governed by the deterministic laws of "phenomenal
A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried W ...
" nature, where every event is completely determined by chains of causality. The most influential formulation was by Immanuel Kant
Immanuel Kant (, , ; 22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and ...
, who distinguished between the causal deterministic framework the mind imposes on the world—the phenomenal realm—and the world as it exists for itself, the noumenal realm, which, as he believed, included free will. To insulate theology from reductionism, 19th century post-Enlightenment German theologians, especially Friedrich Schleiermacher
Friedrich Daniel Ernst Schleiermacher (; 21 November 1768 – 12 February 1834) was a German Reformed theologian, philosopher, and biblical scholar known for his attempt to reconcile the criticisms of the Enlightenment with traditional P ...
and Albrecht Ritschl, used the Romantic
Romantic may refer to:
Genres and eras
* The Romantic era, an artistic, literary, musical and intellectual movement of the 18th and 19th centuries
** Romantic music, of that era
** Romantic poetry, of that era
** Romanticism in science, of that e ...
method of basing religion on the human spirit, so that it is a person's feeling or sensibility about spiritual matters that comprises religion.
Causation
Most common philosophical understandings of causation involve reducing it to some collection of non-causal facts. Opponents of these reductionist views have given arguments that the non-causal facts in question are insufficient to determine the causal facts.
Criticism
Antireductionism
A contrast to reductionism is holism
Holism () is the idea that various systems (e.g. physical, biological, social) should be viewed as wholes, not merely as a collection of parts. The term "holism" was coined by Jan Smuts in his 1926 book ''Holism and Evolution''."holism, n." OED Onl ...
or emergentism
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 int ...
. Holism is the idea that, in the whole, items can have properties, known as ''emergent properties'', that are not explainable from the sum of their parts. The principle of holism was summarized concisely by Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
in the Metaphysics
Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
: "The whole is more than the sum of its parts".
Fragmentalism
An alternative term for ontological reductionism is ''fragmentalism'', often used in a pejorative
A pejorative or slur is a word or grammatical form expressing a negative or a disrespectful connotation, a low opinion, or a lack of respect toward someone or something. It is also used to express criticism, hostility, or disregard. Sometimes, a ...
sense. Anti-realists use the term ''fragmentalism'' in arguments that the world does not exist of separable entities
An entity is something that exists as itself, as a subject or as an object, actually or potentially, concretely or abstractly, physically or not. It need not be of material existence. In particular, abstractions and legal fictions are usually ...
, instead consisting of wholes. For example, advocates of this idea claim that:
The linear deterministic approach to nature and technology promoted a fragmented perception of reality, and a loss of the ability to foresee, to adequately evaluate, in all their complexity, global crises in ecology, civilization and education.
The term ''fragmentalism'' is usually applied to reductionist modes of thought, often with the related pejorative term ''scientism
Scientism is the opinion that science and the scientific method are the best or only way to render truth about the world and reality.
While the term was defined originally to mean "methods and attitudes typical of or attributed to natural scientis ...
''. This usage is popular among some ecological activists: There is a need now to move away from scientism
Scientism is the opinion that science and the scientific method are the best or only way to render truth about the world and reality.
While the term was defined originally to mean "methods and attitudes typical of or attributed to natural scientis ...
and the ideology of cause-and-effect determinism toward a radical empiricism
In philosophy, empiricism is an epistemological theory that holds that knowledge or justification comes only or primarily from sensory experience. It is one of several views within epistemology, along with rationalism and skepticism. Empir ...
, such as William James
William James (January 11, 1842 – August 26, 1910) was an American philosopher, historian, and psychologist, and the first educator to offer a psychology course in the United States.
James is considered to be a leading thinker of the lat ...
proposed, as an epistemology
Epistemology (; ), or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics.
Episte ...
of science.
These perspectives are not new; during the early 20th century, William James
William James (January 11, 1842 – August 26, 1910) was an American philosopher, historian, and psychologist, and the first educator to offer a psychology course in the United States.
James is considered to be a leading thinker of the lat ...
noted that rationalist science emphasized what he called fragmentation and disconnection.
Such opinions also motivate many criticisms of the scientific method:
The scientific method only acknowledges monophasic consciousness. The method is a specialized system that emphasizes studying small and distinctive parts in isolation, which results in fragmented knowledge.
Alternatives
The development of systems thinking
Systems thinking is a way of making sense of the complexity of the world by looking at it in terms of wholes and relationships rather than by splitting it down into its parts. It has been used as a way of exploring and developing effective actio ...
has provided methods that seek to describe issues in a holistic rather than a reductionist way, and many scientists use a holistic paradigm. When the terms are used in a scientific context, holism and reductionism refer primarily to what sorts of models
A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure.
Models c ...
or theories offer valid explanations of the natural world; the scientific method of falsifying hypotheses, checking empirical data against theory, is largely unchanged, but the method guides which theories are considered.
In many cases (such as the kinetic theory of gases
Kinetic (Ancient Greek: κίνησις “kinesis”, movement or to move) may refer to:
* Kinetic theory, describing a gas as particles in random motion
* Kinetic energy, the energy of an object that it possesses due to its motion
Art and enter ...
), given a good understanding of the components of the system, one can predict all the important properties of the system as a whole. In other systems, especially concerned with life and life's emergent properties ( morphogenesis, autopoiesis, and metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
), emergent properties
In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole.
Emergence ...
of the system are said to be almost impossible to predict from knowledge of the parts of the system. Complexity theory studies systems and properties of the latter type.
Alfred North Whitehead
Alfred North Whitehead (15 February 1861 – 30 December 1947) was an English mathematician and philosopher. He is best known as the defining figure of the philosophical school known as process philosophy, which today has found applicat ...
's metaphysics opposed reductionism. He refers to this as the "fallacy of the misplaced concreteness". His scheme was to frame a rational, general understanding of phenomena, derived from our reality.
Ecologist
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...
Sven Erik Jorgensen
Sven (in Danish and Norwegian, also Svend and also in Norwegian most commonly Svein) is a Scandinavian first name which is also used in the Low Countries and German-speaking countries. The name itself is Old Norse for "young man" or "young warri ...
makes both theoretical and practical arguments for a holistic method in certain topics of science, especially ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...
. He argues that many systems are so complex that they can never be described in complete detail. In analogy to the Heisenberg uncertainty principle
In quantum mechanics, the uncertainty principle (also known as Heisenberg's uncertainty principle) is any of a variety of mathematical inequalities asserting a fundamental limit to the accuracy with which the values for certain pairs of physic ...
in physics, he argues that many interesting ecological phenomena cannot be replicated in laboratory conditions, and so cannot be measured or observed without changing the system in some way. He also indicates the importance of inter-connectedness in biological systems. He believes that science can only progress by outlining questions that are unanswerable and by using models that do not try to explain everything in terms of smaller hierarchical levels of organization, but instead model them on the scale of the system itself, taking into account some (but not all) factors from levels higher and lower in the hierarchy.
In cognitive psychology
Cognitive psychology is the scientific study of mental processes such as attention, language use, memory, perception, problem solving, creativity, and reasoning.
Cognitive psychology originated in the 1960s in a break from behaviorism, which ...
, George Kelly developed "constructive alternativism" as a form of personal construct psychology
Within personality psychology, personal construct theory (PCT) or personal construct psychology (PCP) is a theory of personality and cognition developed by the American psychologist George Kelly in the 1950s.For example: (first published 1955 ...
and an alternative to what he considered "accumulative fragmentalism". For this theory, knowledge is seen as the construction of successful mental models of the exterior world, rather than the accumulation of independent "nuggets of truth".
See also
* Antireductionism
* Antiscience
Antiscience is a set of attitudes that involve a rejection of science and the scientific method. People holding antiscientific views do not accept science as an objective method that can generate universal knowledge. Antiscience commonly manifes ...
* Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
* Eliminativism
Eliminative materialism (also called eliminativism) is a materialist position in the philosophy of mind. It is the idea that majority of the mental states in folk psychology do not exist. Some supporters of eliminativism argue that no coherent ...
* Emergentism
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 int ...
* Fallacy of composition
The fallacy of composition is an informal fallacy that arises when one infers that something is true of the whole from the fact that it is true of some part of the whole. A trivial example might be: "This tire is made of rubber, therefore the ve ...
* Further facts
* Holism
Holism () is the idea that various systems (e.g. physical, biological, social) should be viewed as wholes, not merely as a collection of parts. The term "holism" was coined by Jan Smuts in his 1926 book ''Holism and Evolution''."holism, n." OED Onl ...
* Holistic science Holism in science, holistic science, or methodological holism is an approach to research that emphasizes the study of complex systems. Systems are approached as coherent wholes whose component parts are best understood in context and in relation to ...
* Materialism
Materialism is a form of philosophical monism which holds matter to be the fundamental substance in nature, and all things, including mental states and consciousness, are results of material interactions. According to philosophical materiali ...
* Multiple realizability was used as a source of arguments against reductionism.
* Philosophy of 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 addre ...
* Physicalism
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 substanc ...
* Physical ontology
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 substanc ...
* Scientism
Scientism is the opinion that science and the scientific method are the best or only way to render truth about the world and reality.
While the term was defined originally to mean "methods and attitudes typical of or attributed to natural scientis ...
* Symmetry breaking
* Theology
Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...
* Technological determinism
* ''Two Dogmas of Empiricism
"Two Dogmas of Empiricism" is a paper by analytic philosopher Willard Van Orman Quine published in 1951. According to University of Sydney professor of philosophy Peter Godfrey-Smith, this "paper ssometimes regarded as the most important in all ...
''
References
Further reading
* Churchland, Patricia (1986),
Neurophilosophy: Toward a Unified Science of the Mind-Brain
'. MIT Press.
* Dawkins, Richard (1976), '' The Selfish Gene''. Oxford University Press; 2nd edition, December 1989.
* Dennett, Daniel C. (1995) ''Darwin's Dangerous Idea''. Simon & Schuster.
* Descartes (1637), ''Discourses'', Part V.
* Dupre, John (1993),
The Disorder of Things
'. Harvard University Press.
* Galison, Peter and David J. Stump, eds. (1996), ''The Disunity of the Sciences: Boundaries, Contexts, and Power''. Stanford University Press.
* Jones, Richard H. (2013), ''Analysis & the Fullness of Reality: An Introduction to Reductionism & Emergence''. Jackson Square Books.
* Laughlin, Robert (2005), ''A Different Universe: Reinventing Physics from the Bottom Down.'' Basic Books.
* Nagel, Ernest (1961), ''The Structure of Science''. New York.
* Pinker, Steven (2002), ''The Blank Slate: The Modern Denial of Human Nature''. Viking Penguin.
* Ruse, Michael (1988), ''Philosophy of Biology''. Albany, NY.
* Rosenberg, Alexander
Alexander Rosenberg (who generally publishes as "Alex") is an American philosopher and novelist. He is the R. Taylor Cole Professor of Philosophy at Duke University, well known for contributions to philosophy of biology and philosophy of economic ...
(2006), ''Darwinian Reductionism or How to Stop Worrying and Love Molecular Biology''. University of Chicago Press.
* Eric Scerri The reduction of chemistry to physics has become a central aspect of the philosophy of chemistry. See several articles by this author.
* Weinberg, Steven
Steven Weinberg (; May 3, 1933 – July 23, 2021) was an American theoretical physicist and Nobel laureate in physics for his contributions with Abdus Salam and Sheldon Glashow to the unification of the weak force and electromagnetic interactio ...
(1992), ''Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature'', Pantheon Books.
* Weinberg, Steven
Steven Weinberg (; May 3, 1933 – July 23, 2021) was an American theoretical physicist and Nobel laureate in physics for his contributions with Abdus Salam and Sheldon Glashow to the unification of the weak force and electromagnetic interactio ...
(2002) describes what he terms the culture war among physicists in his review of '' A New Kind of Science''.
* Capra, Fritjof (1982), ''The Turning Point''.
* Lopez, F., Il pensiero olistico di Ippocrate. Riduzionismo, antiriduzionismo, scienza della complessità nel trattato sull'Antica Medicina, vol. IIA, Ed. Pubblisfera, Cosenza Italy 2008.
* Maureen L Pope, ''Personal construction of formal knowledge,'' Humanities Social Science and Law, 13.4, December, 1982, pp. 3–14
* Tara W. Lumpkin, ''Perceptual Diversity: Is Polyphasic Consciousness Necessary for Global Survival?'' December 28, 2006
bioregionalanimism.com
* Vandana Shiva, 1995, ''Monocultures, Monopolies and the Masculinisation of Knowledge.'' International Development Research Centre (IDRC) Reports: Gender Equity. 23: 15–17
* The Anti-Realist Side of the Debate: A Theory's Predictive Success does not Warrant Belief in the Unobservable Entities it Postulates Andre Kukla and Joel Walmsley.
External links
* Alyssa Ney
"Reductionism"
in: ''Internet Encyclopedia of Philosophy
The ''Internet Encyclopedia of Philosophy'' (''IEP'') is a scholarly online encyclopedia, dealing with philosophy, philosophical topics, and philosophers. The IEP combines open access publication with peer reviewed publication of original pape ...
''.
* Ingo Brigandt and Alan Love
"Reductionism in Biology"
in: ''The Stanford Encyclopedia of Philosophy''.
an interview at the Galilean Library covering criticisms of reductionism.
Monica Anderson: Reductionism Considered Harmful
Reduction and Emergence in Chemistry
''Internet Encyclopedia of Philosophy''.
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Metatheory of science
Metaphysical theories
Sociological theories
Analytic philosophy
Epistemology of science
Cognition
Epistemological theories
Emergence