Closed concept
Encyclopedia
A closed concept is a concept where all the necessary and sufficient conditions
required to include something within the concept can be listed. For example, the concept of a triangle
is closed because a three-sided polygon, and only a three-sided polygon, is a triangle. All the conditions required to call something a triangle can be, and are, listed.
Necessary and sufficient conditions
In logic, the words necessity and sufficiency refer to the implicational relationships between statements. The assertion that one statement is a necessary and sufficient condition of another means that the former statement is true if and only if the latter is true.-Definitions:A necessary condition...
required to include something within the concept can be listed. For example, the concept of a triangle
Triangle
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
is closed because a three-sided polygon, and only a three-sided polygon, is a triangle. All the conditions required to call something a triangle can be, and are, listed.
External links
- Open and Closed Concepts and the Continuum Fallacy - More on open and closed concepts
- Necessary Conditions and Sufficient Conditions - A guide to the usage and application of necessary and sufficient conditions