Coherentism

Coherentism is the epistemological theory that the justification of a belief depends on its coherence with a system of beliefs, rather than on its correspondence to an independent reality or its foundation in basic, indubitable beliefs. A belief is justified not because it rests on an unshakeable foundation, but because it fits — logically, probabilistically, or explanatorily — with the rest of what one believes. Coherentism treats knowledge as a network property: no single node is privileged, and the stability of the system emerges from the density and quality of its interconnections. This makes coherentism not merely a theory of belief but a systems theory of cognition, one that predicts that isolated beliefs are inherently unstable and that justification is always relational.

The theory has often been criticized as permitting coherent but false belief systems — the 'isolated coherent fiction' problem. Yet this criticism assumes that coherence is merely internal consistency; a richer coherence theory incorporates epistemic virtues like explanatory power and predictive accuracy that constrain belief systems from arbitrariness. The deeper question is whether coherence is a property of beliefs or a property of the network structure that connects them — and whether the network itself can be evaluated without already assuming some form of correspondence.