Coherentism

Coherentism rejects the idea that some beliefs are self-standing foundations and instead holds that a belief is justified by how well it hangs together with the rest of one's beliefs, so that justification is a property of the whole system rather than of beliefs taken one at a time.

Definition

Coherentism is the theory that the justification of a belief consists wholly in its standing in appropriate coherence relations to other beliefs in the same system, with no beliefs justified independently of that system.

Scope

This topic covers the coherentist alternative to foundationalism: the claim that justification is holistic and that nothing outside the believer's system of beliefs can confer justification. It includes accounts of what coherence consists in — logical consistency, explanatory and probabilistic relations, and mutual support — and the standard objections of isolation, alternative coherent systems, and the role of perceptual input. Foundationalism and infinitism appear only as contrasts.

Core questions

• What relations among beliefs constitute coherence — consistency, mutual support, explanatory connection?
• Can a system be justified by internal coherence alone, with no input from experience?
• Why should the coherence of a belief system make its members likely to be true?
• How can coherentism accommodate the apparent role of perception in justifying beliefs?

Key theories

Holistic coherentism

Justification is a property the whole belief system has primarily and individual beliefs only derivatively; a belief is justified if it belongs to a system whose members are mutually supporting and explanatorily integrated.

Coherence with the observation requirement

To avoid isolation from the world, BonJour adds that a coherent system must include reliable spontaneous beliefs answering to experience, so that perceptual input constrains the system without functioning as a foundation.

History

Coherentist themes appear in idealist theories of truth and in Neurath's image of rebuilding a ship plank by plank at sea, and were sharpened in reaction to the difficulties of empiricist foundationalism. BonJour's 1985 statement is the most developed defence; he later abandoned coherentism for a form of foundationalism, illustrating the unresolved tension between the two structures that Sosa dramatised as the raft versus the pyramid.

Debates

The isolation and alternative-systems objections

Critics charge that coherence alone cannot connect a belief system to reality, since a perfectly coherent system could be wholly false and equally coherent rival systems could exist; coherentists respond by building observational constraints into coherence, which critics say reintroduces foundations.

Key figures

• Laurence BonJour
• Keith Lehrer
• Ernest Sosa

Seminal works

• bonjour1985
• sosa1980

Frequently asked questions

How does coherentism differ from foundationalism?

Foundationalism posits a special class of basic beliefs that are justified independently of others; coherentism denies any such class and holds that every belief owes its justification to its fit with the surrounding system, making justification holistic rather than linear.

What is the isolation objection?

It is the worry that a belief system could be internally coherent yet completely cut off from the world and from experience, so that coherence by itself gives no reason to think the beliefs are true. Coherentists answer by requiring that the system be responsive to observation.