Coherence is a measure of the organization and internal consistency of a system or thought. It is the degree to which components of a system or concept fit together in a consistent and meaningful way. Coherence is essential for effective communication and performance, as it helps to attain a state of unity and order in which ideas connect in a meaningful, logical fashion. Coherence can be seen in the overarching structure of a text, as well as the relationships between its concepts, language, and themes. Coherence is an integral part of communication that can provide focus, organization, accuracy and believability to messages.

See also: emergence, evolution, quantum mechanics, self-organization