Overview

Coherentism is a theory of justification which holds that a belief is justified if and only if it coheres with a system of other beliefs. It rejects the idea that there are “basic” beliefs that serve as a foundation for all others.

Core Idea

The core idea is that beliefs are like a web or a raft. No single belief stands alone; each supports and is supported by others. Justification is holistic rather than linear.

Formal Definition

Coherentism is the view that the justification of any belief depends on that belief’s coherence with the agent’s entire system of beliefs. Coherence typically involves logical consistency, explanatory relations, and inductive support.

Intuition

Think of a crossword puzzle. You fill in “cat” for 1-Across. You are justified in this not just because the clue suggests it, but because it fits with “act” at 1-Down and “top” at 2-Down. If a new word doesn’t fit the pattern, you question it or the surrounding words. The whole puzzle supports itself.

Examples

  • Scientific Theories: A theory is accepted because it fits well with existing data, other accepted theories, and mathematical principles.
  • Criminal Investigation: Detectives build a case where the motive, opportunity, and physical evidence all fit together into a coherent narrative.
  • The “Web of Belief”: Quine’s metaphor that our beliefs form a web; experience touches the edges, but changes ripple through the system to maintain consistency.

Common Misconceptions

  • Misconception: Any consistent story is true (e.g., a perfect fairy tale).
    • Correction: Coherence is a necessary condition for justification, but most coherentists also require some connection to empirical input (though how this works without foundations is a challenge).
  • Misconception: Coherentism is circular reasoning.
    • Correction: Coherentists argue it is not a vicious circle but a virtuous, mutually supporting system.
  • Foundationalism: The opposing view that knowledge rests on basic, self-justifying beliefs.
  • Holism: The idea that parts cannot be understood independently of the whole.
  • Neurath’s Boat: A metaphor comparing knowledge to a boat that must be repaired plank by plank while at sea (we cannot dismantle it all at once).

Applications

  • Artificial Intelligence: Consistency checking in knowledge bases.
  • Legal Reasoning: Assessing the coherence of a witness’s story or a legal argument.
  • Hermeneutics: Interpreting texts by making the parts cohere with the whole.

Criticism and Limitations

  • Isolation Objection: A system of beliefs could be perfectly coherent but completely detached from reality (like a detailed delusion).
  • Alternative Systems: There could be two incompatible systems that are equally coherent. How do we choose?
  • Input Problem: How does sensory experience enter the system if justification is only about the relation between beliefs?

Further Reading

  • The Coherence Theory of Truth by Brand Blanshard
  • Empiricism and the Philosophy of Mind by Wilfrid Sellars
  • Two Dogmas of Empiricism by W.V.O. Quine