In epistemology, coherentism is a theory that justification is primarily a matter of coherence among beliefs. That is, justification is not founded on bedrock more certain than the beliefs themselves, as foundationalism claims, but rather it depends only on the logical relationships between various beliefs. In this respect, coherentism stands in opposition to foundationalism.
The Coherentist Picture of Knowledge
On the coherentist picture of knowledge, justification ultimately rests on an infinite regress of supporting premises. beliefs can be justified by other beliefs, which are in turn justified by other beliefs, and so on indefinitely. However, this does not mean that coherentism cannot account for certain kinds of basic knowledge. For example, if we have a belief that there is a ball in front of us, and this belief is supported by other beliefs about the ball’s color, size, etc., then we can say that our belief is justified by coherence with other beliefs. In other words, our justification for the ball-in-front-of-us belief doesn’t ultimately rest on any particular belief being more certain than any other. Rather, it rests on the logical relationships between various beliefs.
This way of thinking about justification has some important consequences. First, it means that justification is not something that can be achieved once and for all. We can never know for sure that our system of beliefs is fully coherent; new information can always come along and disrupt the coherence. Second, it means that justification is not a matter of our individual experiences or intuition; rather, it depends on how well our system of beliefs hangs together as a whole.
Coherentism is an interesting philosophy because it takes a very different approach to justifying our beliefs than other philosophies do. Where foundationalism relies on basic truths that we can know for certain, coherentism relies only on logical relations between various beliefs. This has some important implications for how we think about justification and knowledge.