The main difference between Concept and Theory is that the Concept is a mental representation or an abstract object or an ability and Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking
Concepts are the fundamental building blocks of our thoughts and beliefs. They play an important role in all aspects of cognition.
Concepts arise as abstractions or generalisations from experience; from the result of a transformation of existing ideas; or from innate properties. 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.
In metaphysics, and especially ontology, a concept is a fundamental category of existence. 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
Concepts can be organized into a hierarchy, higher levels of which are termed “superordinate” and lower levels termed “subordinate”. Additionally, there is the “basic” or “middle” level at which people will most readily categorize a concept. For example, a basic-level concept would be “chair”, with its superordinate, “furniture”, and its subordinate, “easy chair”.
A theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context, the results might, for example, include generalized explanations of how nature works. The word has its roots in ancient Greek, but in modern use it has taken on several related meanings.
Theories guide the enterprise of finding facts rather than of reaching goals, and are neutral concerning alternatives among values. A theory can be a body of knowledge, which may or may not be associated with particular explanatory models. To theorize is to develop this body of knowledge.
As already in Aristotle’s definitions, theory is very often contrasted to “practice” (from Greek praxis, πρᾶξις) a Greek term for doing, which is opposed to theory because pure theory involves no doing apart from itself. A classical example of the distinction between “theoretical” and “practical” uses the discipline of medicine: medical theory involves trying to understand the causes and nature of health and sickness, while the practical side of medicine is trying to make people healthy. These two things are related but can be independent, because it is possible to research health and sickness without curing specific patients, and it is possible to cure a patient without knowing how the cure worked.
In modern science, the term “theory” refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that any scientist in the field is in a position to understand and either provide empirical support (“verify”) or empirically contradict (“falsify”) it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge, in contrast to more common uses of the word “theory” that imply that something is unproven or speculative (which is better characterized by the word hypothesis). Scientific theories are distinguished from hypotheses, which are individual empirically testable conjectures, and from scientific laws, which are descriptive accounts of how nature behaves under certain conditions.
abstract and general idea; an abstraction
understanding retained in the mind, from experience, reasoning and/or imagination; a generalization (generic, basic form), or abstraction (mental impression), of a particular set of instances or occurrences (specific, though different, recorded manifestations of the concept).
In generic programming, a description of supported operations on a type, including their syntax and semantics.
Mental conception; reflection, consideration. 16th-18th c.
A phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed; a hypothesis confirmed by observation, experiment etc. from 17th c.
The underlying principles or methods of a given technical skill, art etc., as opposed to its practice. from 17th c.
A field of study attempting to exhaustively describe a particular class of constructs. from 18th c.
“Knot theory classifies the mappings of a circle into 3-space.”
A hypothesis or conjecture. from 18th c.
A set of axioms together with all statements derivable from them. Equivalently, a formal language plus a set of axioms (from which can then be derived theorems).
“A theory is consistent if it has a model.”
an abstract idea
“structuralism is a difficult concept”
“the concept of justice”
a plan or intention
“the centre has kept firmly to its original concept”
an idea or invention to help sell or publicize a commodity
“a new concept in corporate hospitality”
(of a car or other vehicle) produced as an experimental model to test the viability of innovative design features
“a concept car for next month’s Geneva motor show”
an idea or mental image which corresponds to some distinct entity or class of entities, or to its essential features, or determines the application of a term (especially a predicate), and thus plays a part in the use of reason or language.