A theory maintaining that a proposition will be true if it forms part of a system of mutually coherent propositions which is wider than any rival system. The coherence or consistency in question must of course be definable independently of truth, which may be difficult.
Idealists tend to add, however, that only the system as a whole is fully true, the individual component propositions being only partly true or true to some degree. (Also see: degrees of truth.)
Weaker versions of the theory say that such coherence provides a criterion of truth in some or all cases, truth itself being defined - if at all - in some other way.
H Joachim, The Nature of Truth (1906)