A relation among a number of elements, such as propositions or concepts, that fit together well: consistency; cohesiveness. See practical reasoning for an example.

Philosophers have offered coherence theories of truth, knowledge, and ethics. For example, scientific theories can be justified on the basis of how well they cohere with evidence and other beliefs. Connectionist algorithms have been used to provide computational models of coherence-based inferences, with applications to abduction, impression formation, and analogy.
Paul Thagard