Concept

A concept is a mental symbol, used to denote a class of things in the world. Concepts are mental representations that allows 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. Concepts are the glue that bind entities in the world, and are distinct from 'conceptions', which are the beliefs that we hold about these entities. The use of concepts is necessary to cognitive processes such as categorization, memory, decision making, learning and inference.

Concepts are also sometimes construed as abstract entities. This debate concerns the ontological status of concepts - what they are really like. However, there is no reason to think concepts cannot be mental representations and we will continue with the above description, which is the most widely used in discussions in philosophy and psychology.

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 philosophy, psychology and cognitive science.