Religion and epistemology
Authors: Plantinga Alvin 
Published: September 2018

Epistemology is theory of knowledge; one would therefore expect epistemological discussions of religion to concentrate on the question as to whether one could have knowledge of religious beliefs. However, discussions of religious belief have tended to focus on arguments for and against the existence of God: the traditional theistic arguments on the one hand and, on the other, such arguments against the existence of God as the argument from evil.
To see why, we must think about evidentialism with respect to religious belief (‘evidentialism’ for short), the doctrine that a religious believer must have evidence for their beliefs if they are to be rationally justified. In particular, they must have propositional evidence: evidence from other things they believe, evidence that can be put forward in the form of argument. And going with evidentialism is the evidentialist objection to religious belief: the objection that religious belief is unjustified because there is not enough evidence for it. Evidentialism begins with the classical foundationalists René Descartes and (especially) John Locke. According to Descartes and Locke, some beliefs are certain for us. There are two kinds of certain belief: first, self-evident beliefs, such as ‘2 + 1 = 3’, and second, beliefs about one’s own mental life, such as ‘it now seems to me that I see a hand’. According to Locke, I am, of course, clearly justified in accepting those beliefs that are certain; indeed, it is not within my power to reject them. For any belief that is not certain, however, I am justified in accepting it only if I can see that it is probable or likely with respect to beliefs that are certain for me.
What is this ‘justification’ and why does it matter whether or not my beliefs have it? Locke believed that human beings are rational creatures: creatures capable of forming, holding and criticizing beliefs. And rational creatures, he thought, have an intellectual duty to believe only those propositions they can see to be probable with respect to beliefs that are certain for them. This is our duty as rational agents. And justification, as Locke thinks of it, is simply the condition of being within your rights, of not having gone against your duties. You are justified in doing a given thing if it is not contrary to duty for you to do it.
Locke’s view of this matter has been extremely influential among epistemologists in general and among those who think about the epistemology of religious belief in particular. Furthermore, given his views it is easy to see why there should be so much concern with proofs or arguments for the existence of God. It is not self-evident that God exists – otherwise there would be no atheists and agnostics – and of course the belief that God exists is not about one’s own mental life. But then, according to this Lockean way of thinking, anyone who accepts this belief must see that it is probable with respect to what is certain for them, else they will be going contrary to their duty and deserve blame and disapprobation. And proofs or arguments are just the vehicles by means of which one sees (and shows) that a given belief is probable with respect to what is certain.
Evidentialism has come to seem less compelling. First, the whole history of Western philosophy from Descartes to Hume shows that there is little one can really see to be probable with respect to what is certain. If we may only believe propositions that meet that condition, then most of what we believe – that there is an external world, that there are other people, that there has been a past – will not be (or will not clearly be) justified. And second, on sober reflection it just does not seem that there really is a duty to restrict belief to what is probable with respect to what is certain.
If we step back for a broader look, we can distinguish two different kinds of question about religious belief, and two corresponding kinds of criticism or objection. First, there are the claims that religious belief – Christianity, say – is not true: it simply is not true, for example, that there is such a person as God, or that Jesus Christ is the divine son of God. We may call such an objection a de facto objection: the claim is that the religious belief in question is false, is not factual. But there is another kind of criticism or objection as well. Here the claim is not that religious belief is false, but that whether or not it is false, it is in some way improper – unjustified, irrational or in some way not worthy of belief. The evidentialist objection to religious belief is one version of such a de jure criticism of religious belief, and it has been the most prominent objection. But there is another de jure objection that has been increasingly important. This is the objection, raised by Freud, Marx and Nietzsche, that religious belief is irrational. What does that mean? According to Freud, religious belief arises out of illusion or wish-fulfilment: we find ourselves confronted by a cruel and heartless nature that delivers pain, fear and hurt, and in the end demands our death. As a response, we (subconsciously) invent a father in heaven who loves us and is really in charge of nature; otherwise we would sink into depression, stupor and death.
According to Freud, therefore, religious belief arises out of illusion. And the reason this constitutes a criticism of such belief is that this mechanism of illusion is not aimed at the production of true belief, but rather at belief that has some other, non-truth-related property – in this case, the property of enabling us to carry on in this otherwise discouraging world. It is for this reason that religious belief, on this account, is irrational.
This is an intriguing criticism of religious belief. But perhaps the most important thing to see about it is that while it is an allegedly de jure objection to religious belief, it is not really independent of the de facto question. For if Christianity is true, then Christian belief pretty clearly is not irrational in Freud’s sense at all. If it is true, then indeed there is such a person as God, who intends that we should have knowledge of him; and the cognitive processes that produce belief in God and in the other truths of the Christian religion very likely have as their function the production of true belief in us. On the other hand, if Christianity is false, then it is very likely that Christian belief is not produced by cognitive processes whose purpose it is to produce true belief. This de jure criticism of Christian belief, therefore, presupposes that Christian belief is not true; it is viable only if Christian belief is false. If it is intended as a reason for rejecting Christian belief, it is question-begging.
More generally, it seems that there is no sensible de jure epistemic criticism of religious belief that is independent of the de facto question as to the truth of the belief in question. (The evidentialist criticism is a failure and Freud’s complaint is not independent of the de facto question whether the religious belief in question is true.) One fairly common critical attitude towards religious belief can be expressed as follows: ‘As to whether religious belief is true I am completely agnostic – but I do know this: religious belief is irrational.’ The above considerations show that this attitude is at best problematic.