Concepts are mental representations, abstract objects or abilities that make up the fundamental building blocks of thoughts and beliefs. They play an important role in all aspects of cognition.
In contemporary philosophy, there are at least three prevailing ways to understand what a concept is:
In contemporary philosophy, there are at least three prevailing ways to understand what a concept is:
- Concepts as mental representations, where concepts are entities that exist in the mind (mental objects)
- Concepts as abilities, where concepts are abilities peculiar to cognitive agents (mental states)
- Concepts as Fregean senses (see sense and reference), where concepts are abstract objects, as opposed to mental objects and mental states
When the mind makes a generalization such as the concept of tree, it extracts similarities from numerous examples; the simplification enables higher-level thinking.
A concept is instantiated (reified) by all of its actual or potential instances, whether these are things in the real world or other ideas.
Concepts are studied as components of human cognition in the cognitive science disciplines of linguistics, psychology and philosophy,
where an ongoing debate asks whether all cognition must occur through
concepts. Concepts are used as formal tools or models in mathematics, computer science, databases and artificial intelligence where they are sometimes called classes, schema or categories. In informal use the word concept often just means any idea.
Concepts in the representational theory of mind
Within the framework of the representational theory of mind, the structural position of concepts can be understood as follows: Concepts serve as the building blocks of what are called mental representations (colloquially understood as ideas in the mind). Mental representations, in turn, are the building blocks of what are called propositional attitudes
(colloquially understood as the stances or perspectives we take towards
ideas, be it "believing", "doubting", "wondering", "accepting", etc.).
And these propositional attitudes, in turn, are the building blocks of
our understanding of thoughts that populate everyday life, as well as
folk psychology. In this way, we have an analysis that ties our common
everyday understanding of thoughts down to the scientific and
philosophical understanding of concepts.
Nature of concepts
A central question in the study of concepts is the question of what concepts are. Philosophers construe this question as one about the ontology
of concepts – what they are really like. The ontology of concepts
determines the answer to other questions, such as how to integrate
concepts into a wider theory of the mind, what functions are allowed or
disallowed by a concept's ontology, etc. There are two main views of the
ontology of concepts: (1) Concepts are abstract objects, and (2)
concepts are mental representations.
Platonist views of the mind construe concepts as abstract objects.
There is debate as to the relationship between concepts and natural language.
However, it is necessary at least to begin by understanding that the
concept "dog" is philosophically distinct from the things in the world
grouped by this concept – or the reference class or extension. Concepts that can be equated to a single word are called "lexical concepts".
Study of concepts and conceptual structure falls into the disciplines of linguistics, philosophy, psychology, and cognitive science.
In the simplest terms, a concept is a name or label that regards
or treats an abstraction as if it had concrete or material existence,
such as a person, a place, or a thing. It may represent a natural object
that exists in the real world like a tree, an animal, a stone, etc. It
may also name an artificial (man-made) object like a chair, computer,
house, etc. Abstract ideas and knowledge domains such as freedom,
equality, science, happiness, etc., are also symbolized by concepts. It
is important to realize that a concept is merely a symbol, a
representation of the abstraction. The word is not to be mistaken for
the thing. For example, the word "moon" (a concept) is not the large,
bright, shape-changing object up in the sky, but only represents that celestial object. Concepts are created (named) to describe, explain and capture reality as it is known and understood.
A priori concepts
Kant maintained the view that human minds possess pure or a priori
concepts. Instead of being abstracted from individual perceptions, like
empirical concepts, they originate in the mind itself. He called these
concepts categories, in the sense of the word that means predicate, attribute, characteristic, or quality. But these pure categories are predicates of things in general,
not of a particular thing. According to Kant, there are twelve
categories that constitute the understanding of phenomenal objects. Each
category is that one predicate which is common to multiple empirical
concepts. In order to explain how an a priori concept can relate to individual phenomena, in a manner analogous to an a posteriori concept, Kant employed the technical concept of the schema.
He held that the account of the concept as an abstraction of experience
is only partly correct. He called those concepts that result from
abstraction "a posteriori concepts" (meaning concepts that arise out of
experience). An empirical or an a posteriori concept is a general representation (Vorstellung) or non-specific thought of that which is common to several specific perceived objects (Logic, I, 1., §1, Note 1).
A concept is a common feature or characteristic. Kant investigated the way that empirical a posteriori concepts are created.
The logical acts of the understanding by which concepts are generated as to their form are:
In order to make our mental images into concepts, one must thus be able to compare, reflect, and abstract, for these three logical operations of the understanding are essential and general conditions of generating any concept whatever. For example, I see a fir, a willow, and a linden. In firstly comparing these objects, I notice that they are different from one another in respect of trunk, branches, leaves, and the like; further, however, I reflect only on what they have in common, the trunk, the branches, the leaves themselves, and abstract from their size, shape, and so forth; thus I gain a concept of a tree.
- comparison, i.e., the likening of mental images to one another in relation to the unity of consciousness;
- reflection, i.e., the going back over different mental images, how they can be comprehended in one consciousness; and finally
- abstraction or the segregation of everything else by which the mental images differ ...
— Logic, §6
Embodied content
In cognitive linguistics,
abstract concepts are transformations of concrete concepts derived from
embodied experience. The mechanism of transformation is structural
mapping, in which properties of two or more source domains are
selectively mapped onto a blended space. A common class of blends are metaphors. This theory contrasts with the rationalist view that concepts are perceptions (or recollections, in Plato's
term) of an independently existing world of ideas, in that it denies
the existence of any such realm. It also contrasts with the empiricist
view that concepts are abstract generalizations of individual
experiences, because the contingent and bodily experience is preserved
in a concept, and not abstracted away. While the perspective is
compatible with Jamesian pragmatism, the notion of the transformation of
embodied concepts through structural mapping makes a distinct
contribution to the problem of concept formation.
Ontology
Plato
was the starkest proponent of the realist thesis of universal concepts.
By his view, concepts (and ideas in general) are innate ideas that were
instantiations of a transcendental world of pure forms that lay behind
the veil of the physical world. In this way, universals were explained
as transcendent objects. Needless to say this form of realism was tied
deeply with Plato's ontological projects. This remark on Plato is not of
merely historical interest. For example, the view that numbers are
Platonic objects was revived by Kurt Gödel as a result of certain puzzles that he took to arise from the phenomenological accounts.
Gottlob Frege,
founder of the analytic tradition in philosophy, famously argued for
the analysis of language in terms of sense and reference. For him, the
sense of an expression in language describes a certain state of affairs
in the world, namely, the way that some object is presented. Since many
commentators view the notion of sense as identical to the notion of
concept, and Frege regards senses as the linguistic representations of
states of affairs in the world, it seems to follow that we may
understand concepts as the manner in which we grasp the world.
Accordingly, concepts (as senses) have an ontological status
(Morgolis:7).
According to Carl Benjamin Boyer, in the introduction to his The History of the Calculus and its Conceptual Development,
concepts in calculus do not refer to perceptions. As long as the
concepts are useful and mutually compatible, they are accepted on their
own. For example, the concepts of the derivative and the integral
are not considered to refer to spatial or temporal perceptions of the
external world of experience. Neither are they related in any way to
mysterious limits
in which quantities are on the verge of nascence or evanescence, that
is, coming into or going out of existence. The abstract concepts are now
considered to be totally autonomous, even though they originated from
the process of abstracting or taking away qualities from perceptions
until only the common, essential attributes remained.
Mental representations
In a physicalist theory of mind,
a concept is a mental representation, which the brain uses to denote a
class of things in the world. This is to say that it is literally, a
symbol or group of symbols together made from the physical material of
the brain.
Concepts are mental representations that allow us to draw appropriate
inferences about the type of entities we encounter in our everyday
lives. Concepts do not encompass all mental representations, but are merely a subset of them. The use of concepts is necessary to cognitive processes such as categorization, memory, decision making, learning, and inference.
Concepts are thought to be stored in long term cortical memory, in contrast to episodic memory of the particular objects and events which they abstract, which are stored in hippocampus. Evidence for this separation comes from hippocampal damaged patients such as patient HM.
The abstraction from the day's hippocampal events and objects into
cortical concepts is often considered to be the computation underlying
(some stages of) sleep and dreaming. Many people (beginning with
Aristotle) report memories of dreams which appear to mix the day's
events with analogous or related historical concepts and memories, and
suggest that they were being sorted or organized into more abstract
concepts. ("Sort" is itself another word for concept, and "sorting"
thus means to organize into concepts.)
Notable theories on the structure of concepts
Classical theory
The classical theory of concepts, also referred to as the empiricist theory of concepts, is the oldest theory about the structure of concepts (it can be traced back to Aristotle), and was prominently held until the 1970s. The classical theory of concepts says that concepts have a defined structure.
Adequate definitions of the kind required by this theory usually take
the form of a list of features. These features must have two important
qualities to provide a comprehensive definition. Features entailed by the definition of a concept must be both necessary and sufficient for membership in the class of things covered by a particular concept.
A feature is considered necessary if every member of the denoted class
has that feature. A feature is considered sufficient if something has
all the parts required by the definition. For example, the classic example bachelor is said to be defined by unmarried and man.
An entity is a bachelor (by this definition) if and only if it is both
unmarried and a man. To check whether something is a member of the
class, you compare its qualities to the features in the definition. Another key part of this theory is that it obeys the law of the excluded middle, which means that there are no partial members of a class, you are either in or out.
The classical theory persisted for so long unquestioned because
it seemed intuitively correct and has great explanatory power. It can
explain how concepts would be acquired, how we use them to categorize
and how we use the structure of a concept to determine its referent
class. In fact, for many years it was one of the major activities in philosophy – concept analysis.
Concept analysis is the act of trying to articulate the necessary and
sufficient conditions for the membership in the referent class of a
concept. For example, Shoemaker's classic "Time Without Change"
explored whether the concept of the flow of time can include flows
where no changes take place, though change is usually taken as a
definition of time.
Arguments against the classical theory
Given that most later theories of concepts were born out of the rejection of some or all of the classical theory,
it seems appropriate to give an account of what might be wrong with
this theory. In the 20th century, philosophers such as Wittgenstein and
Rosch argued against the classical theory. There are six primary
arguments summarized as follows:
- It seems that there simply are no definitions – especially those based in sensory primitive concepts.
- It seems as though there can be cases where our ignorance or error about a class means that we either don't know the definition of a concept, or have incorrect notions about what a definition of a particular concept might entail.
- Quine's argument against analyticity in Two Dogmas of Empiricism also holds as an argument against definitions.
- Some concepts have fuzzy membership. There are items for which it is vague whether or not they fall into (or out of) a particular referent class. This is not possible in the classical theory as everything has equal and full membership.
- Rosch found typicality effects which cannot be explained by the classical theory of concepts, these sparked the prototype theory.
- Psychological experiments show no evidence for our using concepts as strict definitions.
Prototype theory
Prototype theory came out of problems with the classical view of conceptual structure. Prototype theory says that concepts specify properties that members of a class tend to possess, rather than must possess. Wittgenstein, Rosch, Mervis, Berlin, Anglin, and Posner are a few of the key proponents and creators of this theory. Wittgenstein describes the relationship between members of a class as family resemblances. There are not necessarily any necessary conditions for membership, a dog can still be a dog with only three legs. This view is particularly supported by psychological experimental evidence for prototypicality effects.
Participants willingly and consistently rate objects in categories like
'vegetable' or 'furniture' as more or less typical of that class. It seems that our categories are fuzzy psychologically, and so this structure has explanatory power.
We can judge an item's membership to the referent class of a concept by
comparing it to the typical member – the most central member of the
concept. If it is similar enough in the relevant ways, it will be
cognitively admitted as a member of the relevant class of entities.
Rosch suggests that every category is represented by a central exemplar
which embodies all or the maximum possible number of features of a
given category.
According to Lech, Gunturkun, and Suchan explain that categorization
involves many areas of the brain, some of these are; visual association
areas, prefrontal cortex, basal ganglia, and temporal lobe.
Theory-theory
Theory-theory is a reaction to the previous two theories and develops them further. This theory postulates that categorization by concepts is something like scientific theorizing. Concepts are not learned in isolation, but rather are learned as a part of our experiences with the world around us.
In this sense, concepts' structure relies on their relationships to
other concepts as mandated by a particular mental theory about the state
of the world.
How this is supposed to work is a little less clear than in the
previous two theories, but is still a prominent and notable theory.
This is supposed to explain some of the issues of ignorance and error
that come up in prototype and classical theories as concepts that are
structured around each other seem to account for errors such as whale as
a fish (this misconception came from an incorrect theory about what a
whale is like, combining with our theory of what a fish is).
When we learn that a whale is not a fish, we are recognizing that
whales don't in fact fit the theory we had about what makes something a
fish. In this sense, the Theory–Theory of concepts is responding to some
of the issues of prototype theory and classic theory.
Ideasthesia
According to the theory of ideasthesia
(or "sensing concepts"), activation of a concept may be the main
mechanism responsible for creation of phenomenal experiences. Therefore,
understanding how the brain processes concepts may be central to
solving the mystery of how conscious experiences (or qualia) emerge within a physical system e.g., the sourness of the sour taste of lemon. This question is also known as the hard problem of consciousness. Research on ideasthesia emerged from research on synesthesia where it was noted that a synesthetic experience requires first an activation of a concept of the inducer. Later research expanded these results into everyday perception.
There is a lot of discussion on the most effective theory in
concepts. Another theory is semantic pointers, which use perceptual and
motor representations and these representations are like symbols.
Etymology
The term "concept" is traced back to 1554–60 (Latin conceptum – "something conceived").
