TheInfoList

OR:

In
logic Logic is the study of correct reasoning. It includes both Mathematical logic, formal and informal logic. Formal logic is the science of Validity (logic), deductively valid inferences or of logical truths. It is a formal science investigating h ...
and
philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...
(especially
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 ...
), a property is a characteristic of an object; a red object is said to have the property of redness. The property may be considered a form of object in its own right, able to possess other properties. A property, however, differs from individual objects in that it may be instantiated, and often in more than one object. It differs from the logical/mathematical concept of class by not having any concept of
extensionality In logic Logic is the study of correct reasoning. It includes both Mathematical logic, formal and informal logic. Formal logic is the science of Validity (logic), deductively valid inferences or of logical truths. It is a formal science inves ...
, and from the philosophical concept of class in that a property is considered to be distinct from the objects which possess it. Understanding how different individual entities (or particulars) can in some sense have some of the same properties is the basis of the
problem of universals The problem of universals is an ancient question from metaphysics that has inspired a range of philosophical topics and disputes: Should the property (philosophy), properties an object has in common with other objects, such as color and shape, be ...
.

# Terms and usage

A property is any member of a class of entities that are capable of being attributed to objects. Terms similar to ''property'' include ''predicable'', ''attribute'', ''quality'', ''feature'', ''characteristic'', ''type'', ''exemplifiable'', ''predicate'', and ''intensional entity''. Generally speaking, an object is said to ''exemplify'', ''instantiate'', ''bear'', ''have'' or ''possess'' a property if the property can be truly predicated of the object. The collection of objects that possess a property is called the ''extension'' of the property. Properties are said to ''characterize'' or ''inhere in'' objects that possess them. Followers of
Alexius Meinong Alexius Meinong Ritter Ritter (German for "knight") is a designation used as a title of nobility in German-speaking areas. Traditionally it denotes the second-lowest Royal and noble ranks, rank within the nobility, standing above "Edler" an ...
assert the existence of two kinds of predication: existent objects ''exemplify'' properties, while nonexistent objects are said to ''exemplify'', ''satisfy'', ''immanently contain'' or ''be consubstantiated by'' properties that are ''actually'' possessed and are said to ''encode'', ''be determined by'', ''be consociated with'' or ''be constituted by'' properties that are ''merely'' ascribed to objects. For example, since
Pegasus Pegasus ( grc-gre, Πήγασος, Pḗgasos; la, Pegasus, Pegasos) is one of the best known creatures in Greek mythology. He is a winged divine stallion usually depicted as pure white in color. He was sired by Poseidon, in his role as hor ...
is merely mythical, Pegasus encodes the property of being a horse, but Pegasus exemplifies the property of being a character of
Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
as well. Edward Jonathan Lowe even treated ''instantiation'', ''characterization'' and ''exemplification'' as three separate kinds of predication. Broadly construed, examples of properties include redness, the property of being two, the property of being nonexistent, the property of being identical to
Socrates Socrates (; ; –399 BC) was a Greeks, Greek philosopher from Classical Athens, Athens who is credited as the founder of Western philosophy and among the first moral philosophers of the Ethics, ethical tradition of thought. An enigmati ...
, the property of being a desk, the property of being a property, the property of being both round and square, and the property of being heterological. Some philosophers refuse to treat
existence Existence is the ability of an entity to interact with reality. In philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and la ...
as a property, and Peter van Inwagen suggested that one should deny the existence of certain “properties” so as to avoid paradoxes such as Russell’s paradox and Grelling–Nelson paradox, though such moves remain controversial.

# Metaphysical debates

In modern
analytic philosophy Analytic philosophy is a Academic discipline, branch and Philosophical tradition, tradition of philosophy using philosophical analysis, analysis, popular in the Western world and particularly the Anglosphere, which began around the turn of the 2 ...
there are several debates about the fundamental nature of properties. These center around questions such as: Are properties universals or particulars? Are properties real? Are they categorical or dispositional? Are properties physical or mental?

## Universals vs. particulars

At least since
Plato Plato ( ; grc-gre, wikt:Πλάτων, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greeks, Greek philosopher born in Athens during the Classical Greece, Classical period in Ancient Greece. He founded the Platonist school of thou ...
, properties are viewed by numerous philosophers as universals, which are typically capable of being instantiated by different objects. Philosophers opposing this view regard properties as particulars, namely tropes.

## Realism vs. anti-realism

A realist about properties asserts that properties have genuine, mind-independent existence. One way to spell this out is in terms of exact, repeatable, instantiations known as universals. The other realist position asserts that properties are particulars (tropes), which are unique instantiations in individual objects that merely resemble one another to various degrees. Transcendent realism, proposed by
Plato Plato ( ; grc-gre, wikt:Πλάτων, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greeks, Greek philosopher born in Athens during the Classical Greece, Classical period in Ancient Greece. He founded the Platonist school of thou ...
and favored by
Bertrand Russell Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ar ...
, asserts that properties exist even if uninstantiated. Immanent realism, defended by
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
and
David Malet Armstrong David Malet Armstrong (8 July 1926 – 13 May 2014), often D. M. Armstrong, was an Australian philosophy, Australian philosopher. He is well known for his work on metaphysics and the philosophy of mind, and for his defence of a factualist o ...
, contends that properties exist only if instantiated. The anti-realist position, often referred to as
nominalism In metaphysics, nominalism is the view that Universal (metaphysics), universals and abstract objects do not actually exist other than being merely names or labels. There are at least two main versions of nominalism. One version denies the existen ...
claims that properties are names we attach to particulars. The properties themselves have no existence.

## Categoricalism vs. dispositionalism

Properties are often classified as either ''categorical'' and ''dispositional''. Categorical properties concern what something is like, e.g. what qualities it has. Dispositional properties, on the other hand, involve what powers something has, what it is able to do, even if it is not actually doing it. For example, the shape of a sugar cube is a categorical property while its tendency to dissolve in water is a dispositional property. For many properties there is a lack of consensus as to how they should be classified, for example, whether colors are categorical or dispositional properties. According to categoricalism, dispositions reduce to causal bases. On this view, the fragility of a wine glass, a dispositional property, is not a fundamental feature of the glass since it can be explained in terms of the categorical property of the glass's micro-structural composition. Dispositionalism, on the other hand, asserts that a property is nothing more than a set of causal powers. Fragility, according to this view, identifies a real property of the glass (e.g. to shatter when dropped on a sufficiently hard surface). Several intermediary positions exist. The Identity view states that properties are both categorical (qualitative) and dispositional; these are just two ways of viewing the same property. One hybrid view claims that some properties are categorical and some are dispositional. A second hybrid view claims that properties have both a categorical (qualitative) and dispositional part, but that these are distinct ontological parts.

## Physicalism, idealism, and property dualism

Property dualism describes a category of positions in the
philosophy of mind Philosophy of mind is a branch of philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often ...
which hold that, although the world is constituted of just one kind of
substance Substance may refer to: * Matter, anything that has mass and takes up space Chemistry * Chemical substance, a material with a definite chemical composition * Drug substance ** Substance abuse, drug-related healthcare and social policy diagnosis o ...
—the physical kind—there exist two distinct kinds of properties:
physical properties A physical property is any property that is measurable, whose value describes a state of a physical system. The changes in the physical properties of a system can be used to describe its changes between momentary states. Physical properties ar ...
and mental properties. In other words, it is the view that non-physical, mental properties (such as beliefs, desires and emotions) inhere in some physical substances (namely brains). This stands in contrast to physicalism and idealism. Physicalism claims that all properties, include mental properties, ultimately reduce to, or
supervene In philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied o ...
on, physical properties. Metaphysical idealism, by contrast, claims that "something mental (the mind, spirit, reason, will) is the ultimate foundation of all reality, or even exhaustive of reality."

# Types

## Intrinsic and extrinsic

An intrinsic property is a property that an object or a thing has of itself, independently of other things, including its context. An extrinsic (or ''relational'') property is a property that depends on a thing's relationship with other things. The latter is sometimes also called an ''attribute'', since the value of that property is ''given'' to the object via its relation with another object. For example,
mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a body. It was traditionally believed to be related to the physical quantity, quantity of matter in a Physical object, physical body, until the discovery of the atom and par ...
is a physical intrinsic property of any
physical object In common usage and classical mechanics, a physical object or physical body (or simply an object or body) is a collection of matter within a defined contiguous boundary in three-dimensional space. The boundary must be defined and identified by t ...
, whereas
weight In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a Euclidean vector, vector quantity, the gravitational force acting on the object. Others define weigh ...
is an extrinsic property that varies depending on the strength of the gravitational field in which the
respect Respect, also called esteem, is a positive feeling or action shown towards someone or something considered important or held in high esteem or regard. It conveys a sense of admiration for good or valuable qualities. It is also the process of ...
ive object is placed. Another example of a relational property is the ''name'' of a person (an attribute given by the person's parents).

## Essential and accidental

In classical Aristotelian terminology, a ''property'' (Greek: ''idion'', Latin: ''proprium'') is one of the predicables. It is a non- essential quality of a species (like an
accident An accident is an unintended, normally unwanted event that was not directly caused by humans. The term ''accident'' implies that nobody should be Blame, blamed, but the event may have been caused by Risk assessment, unrecognized or unaddressed ...
), but a quality which is nevertheless characteristically present in members of that species. For example, "ability to laugh" may be considered a special characteristic of human beings. However, "laughter" is not an essential quality of the species ''human'', whose Aristotelian definition of "rational animal" does not require laughter. Therefore, in the classical framework, ''properties'' are characteristic qualities that are not truly required for the continued existence of an entity but are, nevertheless, possessed by the entity.

## Determinate and determinable

A property may be classified as either determinate or determinable. A determinable property is one that can get more specific. For example, color is a determinable property because it can be restricted to redness, blueness, etc. A determinate property is one that cannot become more specific. This distinction may be useful in dealing with issues of identity.

## Pure and impure

Impure properties are properties that, unlike pure properties, involve reference to a particular substance in their definition. So, for example, ''being a wife'' is a pure property while ''being the wife of Socrates'' is an impure property due to the reference to the particular "Socrates". Sometimes, the terms ''qualitative'' and ''non-qualitative'' are used instead of ''pure'' and ''impure''. Most but not all ''impure properties'' are extrinsic properties. This distinction is relevant for the principle of
identity of indiscernibles The identity of indiscernibles is an ontology, ontological principle that states that there cannot be separate object (philosophy), objects or wikt:entity, entities that have all their property (philosophy), properties in common. That is, entities ...
, which states that two things are identical if they are indiscernible, i.e. if they share all their properties. This principle is usually defined in terms of pure properties only. The reason for this is that impure properties are not relevant for similarity or discernibility but taking them into consideration nonetheless would result in the principle being trivially true. Another application of this distinction concerns the problem of duplication, for example, in the Twin Earth thought experiment. It is usually held that duplication only involves qualitative identity but perfect duplicates can still differ concerning their ''non-qualitative'' or ''impure'' properties.

## Lovely and suspect

Daniel Dennett Daniel Clement Dennett III (born March 28, 1942) is an American philosopher, writer, and Cognitive science, cognitive scientist whose research centers on the philosophy of mind, philosophy of science, and philosophy of biology, particularly as t ...
distinguishes between lovely properties (such as loveliness itself), which, although they require an observer to be recognised, exist latently in perceivable objects; and suspect properties which have no existence at all until attributed by an observer (such as being suspected of a crime).

# Properties and predicates

The ontological fact that something has a property is typically represented in language by applying a
predicate Predicate or predication may refer to: * Predicate (grammar), in linguistics * Predication (philosophy) * several closely related uses in mathematics and formal logic: **Predicate (mathematical logic) **Propositional function **Finitary relation, o ...
to a subject. However, taking any grammatical predicate whatsoever to be a property, or to have a corresponding property, leads to certain difficulties, such as
Russell's paradox In mathematical logic Mathematical logic is the study of formal logic within 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 ...
and the Grelling–Nelson paradox. Moreover, a real property can imply a host of true predicates: for instance, if X has the property of weighing more than 2 kilos, then the predicates "..weighs more than 1.9 kilos", "..weighs more than 1.8 kilos", etc., are all true of it. Other predicates, such as "is an individual", or "has some properties" are uninformative or vacuous. There is some resistance to regarding such so-called " Cambridge properties" as legitimate. These properties in the widest sense are sometimes referred to as ''abundant properties''. They are contrasted with ''sparse properties'', which include only properties "responsible for the objective resemblances and causal powers of things".

# Role in similarity

The traditional conception of similarity holds that properties are responsible for similarity: two objects are similar because they have a property in common. The more properties they share, the more similar they are. They resemble each other exactly if they share all their properties. For this conception of similarity to work, it is important that only properties relevant to resemblance are taken into account, sometimes referred to as ''sparse properties'' in contrast to ''abundant properties''.

# Relations

The distinction between properties and relations can hardly be given in terms that do not ultimately presuppose it. Relations are true of several particulars, or shared amongst them. Thus the relation "... is taller than ..." holds "between" two individuals, who would occupy the two ellipses ('...'). Relations can be expressed by N-place predicates, where N is greater than 1. Relations should be distinguished from relational properties. For example, ''marriage'' is a relation since it is between two people, but ''being married to X'' is a relational property had by a certain person since it concerns only one person. There are at least some apparent relational properties which are merely derived from non-relational (or 1-place) properties. For instance "A is heavier than B" is a relational ''predicate'', but it is derived from the two non relational properties: the mass of A and the mass of B. Such relations are called external relations, as opposed to the more genuine internal relations. G. E. Moore (December 15, 1919)
"External and Internal Relations"
/ref> Some philosophers believe that all relations are external, leading to a scepticism about relations in general, on the basis that external relations have no fundamental existence.

*
Abstraction Abstraction in its main sense is a conceptual process wherein general rules and concept Concepts are defined as abstract ideas. They are understood to be the fundamental building blocks of the concept behind principles, thoughts and beliefs. T ...
* Autological word * Bradley's regress, a relevant philosophical problem * Doctrine of internal relations *
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 ...
* Grelling–Nelson paradox *
Identity of indiscernibles The identity of indiscernibles is an ontology, ontological principle that states that there cannot be separate object (philosophy), objects or wikt:entity, entities that have all their property (philosophy), properties in common. That is, entities ...
(or "
Leibniz Gottfried Wilhelm (von) Leibniz . ( – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat. He is one of the most prominent figures in both the history of philosophy and the history of mathema ...
's law") *
Intension In any of several fields of study that treat the use of signs — for example, in linguistics Linguistics is the scientific study of human language. It is called a scientific study because it entails a comprehensive, systematic, objectiv ...
*
Property (mathematics) In mathematics, a property is any characteristic that applies to a given Set (mathematics), set. Rigour, Rigorously, a property ''p'' defined for all elements of a set ''X'' is usually defined as a function ''p'': ''X'' → , that is true whenever ...
*
Russell's paradox In mathematical logic Mathematical logic is the study of formal logic within 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 ...
*
Similarity (philosophy) In philosophy, similarity or resemblance is a relation between objects that constitutes how much these objects are alike. Similarity comes in degrees: e.g. oranges are more similar to apples than to the moon. It is traditionally seen as an Relation ...