In
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...
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
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 ...
; 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
Class or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used differentl ...
by not having any concept of
extensionality
In logic, extensionality, or extensional equality, refers to principles that judge objects to be equal if they have the same external properties. It stands in contrast to the concept of intensionality, which is concerned with whether the internal ...
, and from the philosophical concept of
class
Class or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used differentl ...
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 properties an object has in common with other objects, such as color and shape, be considered to exist 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 von Handschuchsheim (17 July 1853 – 27 November 1920) was an Austrian philosopher, a realist known for his unique ontology. He also made contributions to philosophy of mind and theory of value.
Life
Alexius Meinong ...
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 Greek philosopher from Athens who is credited as the founder of Western philosophy and among the first moral philosophers of the ethical tradition of thought. An enigmatic figure, Socrates authored no te ...
,
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
An autological word (also called homological word) is a word that expresses a property that it also possesses (e.g., "word" is a word, "noun" is a noun, "English" is an English word, " pentasyllabic" has five syllables, and "writable" is writab ...
. Some philosophers refuse to treat
existence
Existence is the ability of an entity to interact with reality. In philosophy, it refers to the ontology, ontological Property (philosophy), property of being.
Etymology
The term ''existence'' comes from Old French ''existence'', from Medieval ...
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
In mathematical logic, Russell's paradox (also known as Russell's antinomy) is a set-theoretic paradox discovered by the British philosopher and mathematician Bertrand Russell in 1901. Russell's paradox shows that every set theory that contains a ...
and
Grelling–Nelson paradox
The Grelling–Nelson paradox is an antinomy, or a semantic self-referential paradox, concerning the applicability to itself of the word "heterological", meaning "inapplicable to itself". It was formulated in 1908 by Kurt Grelling and Leonard Nels ...
, though such moves remain controversial.
Metaphysical debates
In modern
analytic philosophy
Analytic philosophy is a branch and tradition of philosophy using analysis, popular in the Western world and particularly the Anglosphere, which began around the turn of the 20th century in the contemporary era in the United Kingdom, United Sta ...
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, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
, properties are viewed by numerous philosophers as
universals
In metaphysics, a universal is what particular things have in common, namely characteristics or qualities. In other words, universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. For exa ...
, which are typically capable of being instantiated by different objects. Philosophers opposing this view regard properties as
particulars
In metaphysics, particulars or individuals are usually contrasted with universals. Universals concern features that can be exemplified by various different particulars. Particulars are often seen as concrete, spatiotemporal entities as opposed to a ...
, 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
In metaphysics, a universal is what particular things have in common, namely characteristics or qualities. In other words, universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. For exa ...
. 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, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
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, ...
, 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 period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
and
David Malet Armstrong
David Malet Armstrong (8 July 1926 – 13 May 2014), often D. M. Armstrong, was an Australian philosopher. He is well known for his work on metaphysics and the philosophy of mind, and for his defence of a factualist ontology, a functiona ...
, contends that properties exist only if instantiated.
The anti-realist position, often referred to as
nominalism
In metaphysics, nominalism is the view that 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 existence of universalsthings t ...
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 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 ...
which hold that, although the world is constituted of just one kind of
substance—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 are o ...
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, supervenience refers to a relation between sets of properties or sets of facts. X is said to supervene on Y if and only if some difference in Y is necessary for any difference in X to be possible. Some examples include:
* Whether t ...
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 property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementar ...
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
Predicable (Lat. praedicabilis, that which may be stated or affirmed, sometimes called ''quinque voces'' or ''five words'') is, in scholastic logic, a term applied to a classification of the possible relations in which a predicate may stand to its ...
. 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 blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researcher ...
), 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
Identity may refer to:
* Identity document
* Identity (philosophy)
* Identity (social science)
* Identity (mathematics)
Arts and entertainment Film and television
* ''Identity'' (1987 film), an Iranian film
* ''Identity'' (2003 film), ...
.
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 ontological principle that states that there cannot be separate objects or entities that have all their properties in common. That is, entities ''x'' and ''y'' are identical if every predicate possessed by ''x'' ...
, which states that two things are identical if they are
indiscernible
In mathematical logic, indiscernibles are objects that cannot be distinguished by any property or relation defined by a formula. Usually only first-order formulas are considered. Examples
If ''a'', ''b'', and ''c'' are distinct and is a set ...
, 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
Twin Earth is a thought experiment proposed by philosopher Hilary Putnam in his papers "Meaning and Reference" (1973) and "The Meaning of 'Meaning (1975). It is meant to serve as an illustration of his argument for semantic externalism, or the vi ...
. 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 scientist whose research centers on the philosophy of mind, philosophy of science, and philosophy of biology, particularly as those fields relat ...
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, Russell's paradox (also known as Russell's antinomy) is a set-theoretic paradox discovered by the British philosopher and mathematician Bertrand Russell in 1901. Russell's paradox shows that every set theory that contains a ...
and the
Grelling–Nelson paradox
The Grelling–Nelson paradox is an antinomy, or a semantic self-referential paradox, concerning the applicability to itself of the word "heterological", meaning "inapplicable to itself". It was formulated in 1908 by Kurt Grelling and Leonard Nels ...
. 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
George Edward Moore (4 November 1873 – 24 October 1958) was an English philosopher, who with Bertrand Russell, Ludwig Wittgenstein and earlier Gottlob Frege was among the founders of analytic philosophy. He and Russell led the turn from ideal ...
(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.
See also
* Abstraction
Abstraction in its main sense is a conceptual process wherein general rules and concepts are derived from the usage and classification of specific examples, literal ("real" or "concrete") signifiers, first principles, or other methods.
"An abstr ...
* Autological word
An autological word (also called homological word) is a word that expresses a property that it also possesses (e.g., "word" is a word, "noun" is a noun, "English" is an English word, " pentasyllabic" has five syllables, and "writable" is writab ...
* Bradley's regress
Bradley's regress is a philosophical problem concerning the nature of relations. It is named after F. H. Bradley who discussed the problem in his 1893 book ''Appearance and Reality''. It bears a close kinship to the issue of the unity of the pro ...
, a relevant philosophical problem
* Doctrine of internal relations The doctrine of internal relations is the philosophical doctrine that all relations are internal to their bearers, in the sense that they are essential to them and the bearers would not be what they are without them. It was a term used in British ...
* 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
The Grelling–Nelson paradox is an antinomy, or a semantic self-referential paradox, concerning the applicability to itself of the word "heterological", meaning "inapplicable to itself". It was formulated in 1908 by Kurt Grelling and Leonard Nels ...
* Identity of indiscernibles
The identity of indiscernibles is an ontological principle that states that there cannot be separate objects or entities that have all their properties in common. That is, entities ''x'' and ''y'' are identical if every predicate possessed by ''x'' ...
(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, logic, mathematics, semantics, semiotics, and philosophy of language — an intension is any property or quality connoted by a word, phrase, or anoth ...
* Property (mathematics)
In mathematics, a property is any characteristic that applies to a given set. Rigorously, a property ''p'' defined for all elements of a set ''X'' is usually defined as a function ''p'': ''X'' → , that is true whenever the property holds; or eq ...
* Russell's paradox
In mathematical logic, Russell's paradox (also known as Russell's antinomy) is a set-theoretic paradox discovered by the British philosopher and mathematician Bertrand Russell in 1901. Russell's paradox shows that every set theory that contains a ...
* 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 ...
References
External links
*
*
{{Authority control
Abstraction
Concepts in logic
Concepts in metaphysics
Mereology
Metaphysical theories
Ontology