Concept

Coherentism

Intro

"What if no belief is special, and each belief stands or falls by how well it fits with all the others?"

Coherentism is one of the two main answers to a basic question in Epistemology: how are beliefs justified?

The competing answer, foundationalism, says some beliefs are basic. They stand on their own. Other beliefs are justified by tracing them back through reasoning to those basic ones. The structure looks like a building. There is a foundation, and there are walls and rooms that rest on it.

Coherentism says no. There are no foundational beliefs. The structure of knowledge looks more like a web. Each strand of the web supports and is supported by the strands next to it. A belief is justified by how well it fits with the other things you believe. The more your beliefs hang together as a coherent system, the more justified each individual belief is.

The classic motivation is dissatisfaction with foundationalism. Foundationalists have a hard time explaining what makes a belief truly foundational. Beliefs about your own current sensations seem like good candidates, but they are surprisingly hard to defend as the kind of secure starting point the whole structure of knowledge needs. Wilfrid Sellars famously attacked this idea as "the Myth of the Given." Coherentism tries to do without the Given entirely.

The most influential modern defenders have been Laurence BonJour (in his earlier work) and Donald Davidson. Both argued in different ways that justification is a property of whole sets of beliefs, not of individual beliefs in isolation.

Two cautions on terminology. There is a coherence theory of truth, which says a belief is true to the extent that it coheres with other beliefs. There is also a coherence theory of justification, which says a belief is justified by coherence, while remaining open about whether truth is something else. Coherentism about justification is what this page covers. The two are logically separable.

Coherentism has real strengths. It explains why scientific theories sometimes need to revise even apparently secure observations when they conflict with the broader system. It captures the way ordinary people actually adjust their beliefs in light of each other. But it also faces serious objections. The most famous is the "isolation objection." If justification is purely internal to a system of beliefs, how do beliefs ever connect to the world? You could have a perfectly coherent web of beliefs that has nothing to do with reality.

For Christian apologetics, coherentism is significant for two reasons. First, the Cumulative Case for Christian Theism is partly a coherentist argument: many independent lines of evidence cohere around the conclusion of theism. Second, Presuppositionalism makes coherentist-style claims about competing worldviews: only the Christian worldview as a whole hangs together.

In full

Coherentism is the epistemological theory of justification holding that a belief is justified by virtue of its coherence with other beliefs in a system, rather than by being inferred from privileged foundational beliefs. There are no purely basic beliefs; justification is a holistic property of a web of beliefs. The view stands opposed to Foundationalism and is typically motivated by dissatisfaction with both the foundationalist's "myth of the given" and the regress problem.

It is important to distinguish coherentism about justification, this entry, from the coherence theory of truth (covered in Theories of Truth). The two often travel together but are logically separable: one can hold that beliefs are justified by coherence while accepting a correspondence account of truth.

Core claim

A belief B is justified for a subject S iff B coheres appropriately with S's other beliefs. "Coherence" includes:

Logical consistency, no contradictions within the system.
Mutual support, beliefs explain and entail one another.
Explanatory richness, beliefs hang together in a way that reveals deep structure.
Comprehensiveness, the system covers a wide range of evidence.

Coherentism rejects the foundationalist regress-stopper. Instead of beliefs justifying beliefs in a linear chain that bottoms out, the structure is holistic, like a raft (Quine's image) rather than a pyramid.

Historical development

Idealist roots

F. H. Bradley, Appearance and Reality (1893); Essays on Truth and Reality (1914), British absolute idealism. Coherence is constitutive of truth and justification.
Brand Blanshard, The Nature of Thought (1939, 2 vols.), the most thorough idealist coherentist account.

Mid-20th century holism

W. V. O. Quine, Two Dogmas of Empiricism (1951); Word and Object (1960), "web of belief" metaphor. No statement is immune to revision; revisions propagate through the holistic web. Quine is more naturalist-holist than coherentist proper, but paved the way.
Wilfrid Sellars, Empiricism and the Philosophy of Mind (1956), attacks "the myth of the given," removing foundationalism's empirical foundation.

The classical defenders

Laurence BonJour, The Structure of Empirical Knowledge (1985), the most rigorous defense of coherentism. (BonJour later renounced coherentism and returned to a moderate foundationalism in In Defense of Pure Reason, 1998, see his Epistemology textbook for the developed view.)
Keith Lehrer, Knowledge (1974); Theory of Knowledge (1990, rev. 2000), coherentism with a "trustworthiness" condition.
Donald Davidson, "A Coherence Theory of Truth and Knowledge" (1983), coherence is a sufficient condition for truth-tracking given a charity-of-interpretation framework.

Strengths

Avoids the regress problem without positing arbitrary foundations.
Avoids the myth of the given: no need to identify a pristine observational layer immune to interpretation.
Matches scientific practice: scientific theories are accepted / revised on holistic grounds, fit with established theory, explanatory power, simplicity, conservation.
Captures reflective equilibrium: Rawls's method in ethics and Goodman's method in logic are coherentist in spirit.

Weaknesses

1. The isolation objection

A coherent belief-system may be entirely isolated from reality. A detailed Tolkien-mythology belief-set is internally coherent but false. Coherence alone cannot guarantee that any belief tracks the world, it is necessary but not sufficient for truth.

This is the most common and most powerful objection (Bertrand Russell, Philosophical Essays, 1910; Schlick, "The Foundation of Knowledge," 1934).

2. The plurality / alternative-systems objection

For any coherent system S, there are indefinitely many alternative coherent systems S', S'', S''', etc., each internally consistent but mutually incompatible. Coherentism alone offers no principled way to choose among them.

3. The input problem

Coherentism gives no privileged role to perception. But surely a new perceptual experience should be allowed to force revision of beliefs from outside the system. If perception is just one belief among others, the system can always "explain it away" by adjusting internal beliefs. This violates our intuition that the world speaks back.

4. Circularity

If belief A is justified by B, B by C, and C by A, the "justification" looks circular. Coherentists reply that the system is justified as a whole, not via small circles, but critics insist that holistic circularity is still circularity.

Two responses

Sophisticated coherentists have tried to address these:

Observation-as-spontaneous-belief (BonJour 1985): perception generates spontaneously formed beliefs that the system must accommodate. This restores something like an input mechanism.
Methodological coherentism (Quine, Lehrer): coherence as the operating method of justification while remaining metaphysically realist about truth.
Foundherentism (Susan Haack, Evidence and Inquiry, 1993): hybrid model, basic experiential anchors + coherence-style mutual support.

Christian engagement

Christian theology engages coherentism in several ways:

Systematic theology is implicitly coherentist, a doctrine is evaluated partly by its fit with the larger doctrinal system (Trinity, Christology, soteriology hang together). cites this directly: "Defending a theological system where doctrines reinforce one another."
Worldview apologetics (Schaeffer, Carson, Sire, Pearcey), the Christian worldview is recommended in part by its coherence across metaphysics, epistemology, ethics, and aesthetics, vs naturalism's internal tensions.
Critique: Christians typically reject pure coherentism in favor of a hybrid in which Scripture / revelation supplies the reality-anchor against the isolation objection (correspondence with God's actual self-disclosure), with coherence as a secondary test.
Presuppositionalist usage: Van Til and Bahnsen use coherence- style internal critique to expose contradictions in non-Christian worldviews, coherence as a negative test even if not the positive constitution of justification.