Reduction (philosophy)
Encyclopedia
In philosophy
, reduction is the process by which one object, property, concept, theory, etc., is shown to be explicable in terms of another, lower level, entity. For example, we say that physical
properties such as the boiling point
of a substance are reducible to that substance’s molecular
properties, because statistical mechanics
explain why a liquid boils at a certain temperature using only the properties of its constituent atoms. Thus we might also describe reduction as a process analogous to absorption, by which one theory (or concept, or property, and so on) is wholly subsumed under another.
In science
, such reduction is generally desirable, because it explains why and how the thing which is being reduced exists, and because it promotes conceptual and theoretical economy. Reducing chemical properties to properties of atoms thus explains these properties and integrates them into a single explanatory framework, that of atomic structure.
Reductionism
may therefore be divided into three general areas – methodological, theoretical, and ontological
– and reduction (the process) into two – theoretical and ontological.
Theoretical reductionism is the position that all scientific theories either can or should be reduced to a single super-theory through the process of theoretical reduction.
Finally, ontological reductionism is the belief that reality is composed of a minimum number of kinds of entities or substances. This claim is usually metaphysical
, and is most commonly a form of monism
, in effect claiming that all objects, properties and events are reducible to a single substance. (A dualist
who is an ontological reductionist would presumably believe that everything is reducible to one of two substances.)
laws of the motion of the planets and Galileo
’s theories of motion worked out 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 to be beneficial because Newtonian mechanics is a more general theory — that is, it explains more events than Galileo's or Kepler's. Theoretical reduction, therefore, is the reduction of one explanation or theory to another — that is, it is the absorption of one of our ideas about a particular thing into another idea.
By contrast, ontological reduction is the process of reducing things themselves to one another. For example, it was once believed that life was an irreducible property of objects
. An ontology of such properties might therefore have read:
All the other properties of an object, such as its shape, color, or mobility are considered to be nothing more than the effects of these irreducible properties. Shape, for example, is a function of in what way the object is extended in space, as is color, since it is determined by how light bounces off a surface, which is in turn determined by how that object is extended in space.
Science now considers that all life forms are alive by virtue of the fact that they are physically organized in such a way that they can reproduce themselves, not because they possess a special property distinct from and in addition to their physical organization. Biologists therefore say the property of life is reducible to the physical properties of an organism; being alive is simply nothing more than having certain physical properties.
. Philosophers welcome this, because every ontological primitive demands a special explanation for its existence. If we maintain that life is not a physical property, for example, then we must give a separate explanation of why some objects possess it and why others do not. This is more often than not a daunting task, and such explanations often have the flavor of ad hoc
contrivances or deus ex machina
. Also, since every ontological primitive must be acknowledged as one of the fundamental principles of the natural world, we must also account for why this element in particular should be considered one of those underlying principles. (To return to an earlier example, it would be extremely difficult to explain why planets are so fundamental that special laws of motion should apply to them.) This is often extremely hard to do, especially in the face of our strong preference for simple explanations. Pursuing ontological reduction thus serves to unify and simplify our ontology, while guarding against needless multiplication of entities in the process.
At the same time, the requirements for satisfactorily showing that one thing is reducible to another are extremely steep. First and foremost, all features of the original property or object must be accounted for. For example, lightning
would not be reducible to the electrical activity of air molecules if the reduction explained why lightning is deadly, but not why it always seeks the highest point to strike. Our preference for simple and unified explanations is a strong force for reductionism, but our demand that all relevant phenomena be accounted for is at least as strong a force against it.
, the Bundle theory
says that objects can be reduced to collections of properties;
so whenever we talk about objects, we can be understood to be talking about bundles of properties. Does this mean that the bundle theory says that objects do not exist? Perhaps not objects as we had thought of them, but the theory is trying to give an account of what objects are; namely, they are bundles of properties. So, the bundle theorist is not denying that objects exist; he or she is affirming that objects are the same as bundles of properties. The only reason one would have for maintaining, then, that the bundle theory holds that objects do not exist is if you think that, according to our ordinary concepts, something simply cannot both be a bundle of properties and an object.
Philosophers mean about the same thing when they talk about what exists ultimately. For example, the bundle theory says that ultimately, properties and bundles thereof exist, rather than objects. The things that exist "ultimately" are precisely the things to which other things are reduced.
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
, reduction is the process by which one object, property, concept, theory, etc., is shown to be explicable in terms of another, lower level, entity. For example, we say that physical
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
properties such as the boiling point
Boiling point
The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
of a substance are reducible to that substance’s molecular
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
properties, because statistical mechanics
Statistical mechanics
Statistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
explain why a liquid boils at a certain temperature using only the properties of its constituent atoms. Thus we might also describe reduction as a process analogous to absorption, by which one theory (or concept, or property, and so on) is wholly subsumed under another.
In science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
, such reduction is generally desirable, because it explains why and how the thing which is being reduced exists, and because it promotes conceptual and theoretical economy. Reducing chemical properties to properties of atoms thus explains these properties and integrates them into a single explanatory framework, that of atomic structure.
Reductionism
Reductionism
Reductionism can mean either an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things or a philosophical position that a complex system is nothing but the sum of its parts, and that an account of it can...
may therefore be divided into three general areas – methodological, theoretical, and ontological
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
– and reduction (the process) into two – theoretical and ontological.
Types of reductionism
Methodological reductionism is the position that the best scientific strategy is to attempt to reduce explanations to the smallest possible entities. Methodological reductionism would thus hold that the atomic explanation of a substance’s boiling point is preferable to the chemical explanation, and that an explanation based on even smaller particles (quarks, perhaps) would be even better.Theoretical reductionism is the position that all scientific theories either can or should be reduced to a single super-theory through the process of theoretical reduction.
Finally, 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
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
, and is most commonly a form of monism
Monism
Monism is any philosophical view which holds that there is unity in a given field of inquiry. Accordingly, some philosophers may hold that the universe is one rather than dualistic or pluralistic...
, in effect claiming that all objects, properties and events are reducible to a single substance. (A dualist
Dualism
Dualism denotes a state of two parts. The term 'dualism' was originally coined to denote co-eternal binary opposition, a meaning that is preserved in metaphysical and philosophical duality discourse but has been diluted in general or common usages. Dualism can refer to moral dualism, Dualism (from...
who is an ontological reductionist would presumably believe that everything is reducible to one of two substances.)
Types of reduction
The distinction between the processes of theoretical and ontological reduction is equally important. Theoretical reduction is the process by which one theory is absorbed into another; for example, both Kepler'sJohannes Kepler
Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...
laws of the motion of the planets and Galileo
Galileo Galilei
Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...
’s theories of motion worked out 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 to be beneficial because Newtonian mechanics is a more general theory — that is, it explains more events than Galileo's or Kepler's. Theoretical reduction, therefore, is the reduction of one explanation or theory to another — that is, it is the absorption of one of our ideas about a particular thing into another idea.
By contrast, ontological reduction is the process of reducing things themselves to one another. For example, it was once believed that life was an irreducible property of objects
Vitalism
Vitalism, as defined by the Merriam-Webster dictionary, is#a doctrine that the functions of a living organism are due to a vital principle distinct from biochemical reactions...
. An ontology of such properties might therefore have read:
- extension in space
- location in space
- is alive
- and so on.
All the other properties of an object, such as its shape, color, or mobility are considered to be nothing more than the effects of these irreducible properties. Shape, for example, is a function of in what way the object is extended in space, as is color, since it is determined by how light bounces off a surface, which is in turn determined by how that object is extended in space.
Science now considers that all life forms are alive by virtue of the fact that they are physically organized in such a way that they can reproduce themselves, not because they possess a special property distinct from and in addition to their physical organization. Biologists therefore say the property of life is reducible to the physical properties of an organism; being alive is simply nothing more than having certain physical properties.
Benefits of reduction
An ontological reduction reduces the number of ontological primitives that exist within our ontologyOntology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
. Philosophers welcome this, because every ontological primitive demands a special explanation for its existence. If we maintain that life is not a physical property, for example, then we must give a separate explanation of why some objects possess it and why others do not. This is more often than not a daunting task, and such explanations often have the flavor of ad hoc
Ad hoc
Ad hoc is a Latin phrase meaning "for this". It generally signifies a solution designed for a specific problem or task, non-generalizable, and not intended to be able to be adapted to other purposes. Compare A priori....
contrivances or deus ex machina
Deus ex machina
A deus ex machina is a plot device whereby a seemingly inextricable problem is suddenly and abruptly solved with the contrived and unexpected intervention of some new event, character, ability, or object.-Linguistic considerations:...
. Also, since every ontological primitive must be acknowledged as one of the fundamental principles of the natural world, we must also account for why this element in particular should be considered one of those underlying principles. (To return to an earlier example, it would be extremely difficult to explain why planets are so fundamental that special laws of motion should apply to them.) This is often extremely hard to do, especially in the face of our strong preference for simple explanations. Pursuing ontological reduction thus serves to unify and simplify our ontology, while guarding against needless multiplication of entities in the process.
At the same time, the requirements for satisfactorily showing that one thing is reducible to another are extremely steep. First and foremost, all features of the original property or object must be accounted for. For example, lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
would not be reducible to the electrical activity of air molecules if the reduction explained why lightning is deadly, but not why it always seeks the highest point to strike. Our preference for simple and unified explanations is a strong force for reductionism, but our demand that all relevant phenomena be accounted for is at least as strong a force against it.
Examples
In metaphysicsMetaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
, the Bundle theory
Bundle theory
Bundle theory, originated by the 18th century Scottish philosopher David Hume, is the ontological theory about objecthood in which an object consists only of a collection of properties, relations or tropes....
says that objects can be reduced to collections of properties;
so whenever we talk about objects, we can be understood to be talking about bundles of properties. Does this mean that the bundle theory says that objects do not exist? Perhaps not objects as we had thought of them, but the theory is trying to give an account of what objects are; namely, they are bundles of properties. So, the bundle theorist is not denying that objects exist; he or she is affirming that objects are the same as bundles of properties. The only reason one would have for maintaining, then, that the bundle theory holds that objects do not exist is if you think that, according to our ordinary concepts, something simply cannot both be a bundle of properties and an object.
Philosophers mean about the same thing when they talk about what exists ultimately. For example, the bundle theory says that ultimately, properties and bundles thereof exist, rather than objects. The things that exist "ultimately" are precisely the things to which other things are reduced.