Friday, July 13, 2012

Criticism of the coherentist theory of knowledge

To: Christian M.
From: Geoffrey Klempner
Subject: Criticism of the coherentist theory of knowledge

Dear Chris,

Thank you for your email of 16 December, with your University of London Epistemology essay, in response to the question, 'My beliefs could form a coherent set even if none of them is true, so the coherence account of knowledge must be wrong.' Discuss.

This is a solid essay.

There is more to say about the question. My first response to the question is that the hypothesis which it puts forward is utterly fantastical. We are talking about the totality of 'my beliefs', not just some set of beliefs. And the claim put forward is that they could ALL be false. Is that really credible?

Consider the belief that 1+1=2. Or, as an example of an empirical belief, 'If you put something somewhere, it stays there until it is moved.' It is very difficult to see how one could even begin to make sense of a person's belief system if it were really claimed that every single belief in the system was false.

I think it is legitimate to attack the question in this way, even though the question can easily be re-formulated in order to meet this point. In my experience, examiners will give you credit for questioning the precise wording of the question, because it shows that you are able to think 'on your feet', and are not just trotting out an essay which you memorized beforehand.

The assumption is that my beliefs are consistent. For most persons this is probably not true: we just don't have the time to compare all our beliefs and determine whether they are all consistent. Logicians give the name 'omega inconsistency' the existence an inconsistency which one is unable to track down: it is not the least bit irrational to admit that one has omega-inconsistent beliefs.

On the assumption that my beliefs are consistent, however, one may hypothesize that very many of my beliefs -- or the most important of my beliefs, such as, 'I am a human being', 'the earth has existed for more than 5 minutes' -- may be false, even though the set as a whole is consistent, and also coherent in the way that beliefs support and explain one another. My beliefs that 1+1=2 and that objects stay where they are unless moved are 'important' in the sense that very drastic consequences would follow if these beliefs were denied, but for this very reason lie in the background. In the foreground are my most consequential beliefs, the beliefs which account for my behaviour (e.g. my belief that I am being pursued by agents of the CIA).

The claim is that my foreground beliefs, my most consequential beliefs could 'all be false', while my belief system as a whole is coherent.

Is this hypothesis acceptable? Here, we need to distinguish between the use of the hypothesis to cast doubt on the coherence theory of knowledge, and the use of the hypothesis to cast doubt on the coherence theory of truth.

If you were defending the coherence theory of truth, then you would have to show that the hypothesis does not describe a logically possible state of affairs. Because the claim is that coherence IS truth. For the purposes of defending a coherence theory of knowledge, on the other hand, one can (for the sake of argument) accept that the hypothesis describes a logically possible state of affairs. It is possible, but extremely unlikely, for the reasons that you articulate.

The next question is, What does this show about the nature of knowledge, as viewed e.g. by a defender of the coherence theory of knowledge?

Knowledge is not absolute certainty. We can be wrong about what we think is 'knowledge'. The test for attributing knowledge to a subject is not so high that any possibility -- even the slimmest logical possibility -- that things might not be as the subject believes shows that his/her belief is not knowledge.

Having relaxed our requirements for knowledge to this extent, the question only remains to show how the coherence view gives a sufficiently credible account of how knowledge claims are justified. As you show, the role of perceptual knowledge is crucial: we don't want to go down the road of foundationalism, yet we do want to recognize the special role of perception in serving not only as a main source of knowledge but also as a main constraint on the formation of beliefs. Stating this, however, requires not a little delicacy.

All the best,