Necessary and Sufficient Conditions for Knowledge

I’ve recently been thinking quite a bit about meta-epistemology. Around this time last year, I wrote some thoughts on necessary and sufficient conditions for knowledge. I’d like to update some of those thoughts here, first [re]quoting something epistemologist Richard Fumerton wrote (link):

The classic test for whether a condition for knowledge, say the truth of what is believed, is analytically necessary is whether or not it is absolutely inconceivable that someone has knowledge while failing to satisfy the condition. The test for whether a conjunction of conditions X is jointly sufficient for knowledge is whether we can conceive of X obtaining without knowledge.

Necessary conditions are most useful when constructing apagogic arguments. They are like tests used to falsify worldviews. They delimit possibilities. Worldviews which reject or have unsound perspectives of principles of logic and language, for instance, cannot account for knowledge. The adherents of these worldviews will accordingly be unable to account for their true opinions, precluding knowledge.

This is relevant to my aim to “marry the intuitive appeal of classical apologetics with the necessity of epistemic preconditions for knowledge” (link). The, or at least a, goal is to instrumentally effect belief with which one can agree but for which the opponent’s epistemic system cannot account. The apologist starts by deconstructing the opponent’s worldview. He shows it to be internally inconsistent, lacking in explanatory power, etc. But this leaves the opponent with a problem. He may intuitively recognize that his system fails to satisfy a necessary condition for knowledge, but how can he account for this recognition without a sufficient condition for knowledge, a precondition for knowledge such that no other epistemic requirement is necessary to explain how he could be certain that what he claims to know [about his or my worldview or any other proposition] is, in fact, true? He can’t. What happens in such a case is that the apologist shows a person his inconsistencies. The person then accepts truth, but he isn’t yet able to justify this. He senses that something is wrong when a person points out his self-defeating propositions, and naturally so, for although his capacity to reason soundly has been lost, he is still able to reason validly.

The sufficient precondition for knowledge he must accept to reason soundly is Scripture. I have provided on this blog several necessary preconditions for knowledge intended to help “delimit the possibilities” and point readers in this direction. The hope is that those who disagree recognize something is wrong with their worldview and that they need to change what they believe. But the simple fact is that one can’t strictly reason from necessary preconditions of knowledge to a sufficient precondition for knowledge. Given that we are not omniscient, it would be speculative to take a collection of necessary conditions and pronounce that they are sufficient for knowledge (indeed, there is a necessary condition for knowledge related to this). It has to be the other way around: one must know the sufficient precondition for knowledge first. This is not to say the alleged sufficient condition will be arbitrary. As already mentioned, it will need to be able to account for all necessary preconditions for knowledge. But ultimately, one must support the idea that some [axiomatic or presuppositional] propositions may be and are internally rather than externally justified. I’ve written more about the mutual dependency between axioms and it attendant theorems here and elsewhere.

Now, it is clear one cannot reject that or those principle[s] which suffice for knowledge yet still possess knowledge, at least given said principle[s] alone suffice[s]. But I think one can reject a necessary principle yet possess knowledge. Why? Because he may simply be being inconsistent; that is, it may be the case that from what he accepts as sufficient follows the necessary principle[s] but that the person does not realize it. If upon a logical examination of a worldview itself the necessary principles would be compatible with it, then the possibility that one might erroneously reject said principles would not mitigate against his worldview and, thus, what he has actually derived from it. 

So when I refer to a “necessary precondition for knowledge,” what I mean is a proposition which must be accountable within a worldview for it to be true. The laws of logic, a philosophy of language, an omniscient source, self-knowledge, etc., must be necessarily possible for Scripturalism as such to be true, though individual Scripturalists really only need to hold to the sufficient condition - divine revelation in general and the Bible (as the extant extent of divine revelation) in particular - by which these propositions may be justified in order to possess knowledge.