Frequent ESN contributor and InterVarsity Christian Fellowship / USA Graduate & Faculty Ministries Staff Mark Hansard explores John Locke’s ideas in Part 4 of his series on faith and reason. As you may remember, Part 1 took a brief look at a Scriptural basis for using reason and logic, Part 2 discussed St. Augustine’s ideas about faith and reason, and Part 3 engaged with the thought of Aquinas. If you’re looking for Advent content this week, check out our Resources for Advent post from last week, and plan to visit Mark’s post Preparing for Epiphany after Christmas.
John Locke (1632–1704) was an influential Enlightenment philosopher who has had, and continues to have, an enormous impact on Western thought, as well as political thought in the U.S. Locke’s famous Essay Concerning Human Understanding (1689) is one in which he discusses faith and reason, among other topics.
An important part to Locke’s project concerned epistemology, a branch of philosophy that defines knowledge. Epistemology deals with questions such as “What is knowledge, and how do we know when we have it?” Locke declared, very narrowly, that knowledge consists of propositions that are immediate to our mental awareness, things such as mathematics, logic, and other abstract ideas. In other words, you could only be certain of what immediately takes place in your mind. And certainty is required for knowledge. One can assent to certain propositions, or believe them, but if they are not immediately aware to the mind, such beliefs do not constitute knowledge because they are not certain. Locke went on to say that, when we are taught particular propositions we take them to be true, and we, generally speaking, ought to hold them with a surety that’s proportionate to the evidence for them.
Thus, when Locke turns to faith and reason, his beliefs about knowledge have interesting consequences. On Locke’s view, faith involves believing revelation. A revelation is a message of some type that is received directly from God. For Locke, faith is not a species of knowledge; “it consists in believing things on the basis of one’s belief that they have been revealed by God rather than on the basis of some demonstration—it being assumed that there is no proposition such that it can be demonstrated that God has revealed that proposition.” In other words, since you cannot provide evidence that God revealed a truth to you, you have faith that it is true, but it cannot be known. If you were certain that it was true, immediately to your mind, you would have knowledge and thus would not have faith. Importantly, for Locke the object of faith is the proposition revealed by God, not the fact that God has revealed the proposition.
Thus, what are your epistemic duties regarding believing revelation? Let us distinguish between proposition p, the proposition God reveals, and that God reveals a proposition p. You are to believe p with a certainty proportional to the evidence that God revealed p. The stronger the evidence that he revealed p, the more surety with which you can believe p. Locke goes on to say that it is not that you must have evidence directly for p in order to believe it; in fact, one advantage of revelation is that one can believe something, directly from God, that, under any other circumstances, one would not be justified in believing.
What then did Locke mean regarding evidence that proposition p has been revealed? He did believe that writers of the Bible received revelation, but not because they had an experience of God; rather it is because the miracles God performed empirically demonstrated that God was revealing his truth to them. Thus, Locke seems to mean that in order for p to be believed, there must be empirical evidence of some sort that p was revealed. Locke did believe that one could hold a proposition to be true both by faith and by reason. But his system clearly privileges reason over faith by saying that reason results in knowledge and faith does not. “Reason must be our last Judge and Guide in every Thing,” he says, arguing that empirical methods of pursuing knowledge ought to apply to religious beliefs.
Thus, Locke famously attacked religious believers who claimed to have revelation from God. It wasn’t just that they couldn’t know God had revealed something to them, it was that their reasoning about how they knew it to be true was circular. If you asked how they knew p to be true, they would say, “Because God revealed it.” How do you know he revealed it? “I know God revealed it because I am certain that he did.” In essence, “I am sure because I am sure.” The issue for Locke, then, is not that if God revealed something, how we can know it is true? Locke thinks that it necessarily would be, because God can’t lie. But he thinks that, because we can never be certain that God has revealed a proposition because we cannot empirically demonstrate that he has (except by miracles), then revelation as a basis for faith will never be certain or count as knowledge. We cannot be certain that a revelation has occurred, neither can we be certain we have interpreted that revelation correctly.
It seems to me, and to many others, that this is an unnecessarily skeptical position, and has done damage to the cause of Christ over the centuries. Today, many philosophers have abandoned Locke’s epistemological project—including what he said about religious knowledge and scientific knowledge. Reformed epistemologists, for example, have argued along these lines: You can have an experience of God, or a revelation from God, and it be revealed immediately to your awareness. If revealed immediately to the awareness, you are rationally justified in believing it to be true and believing it to be from God, in the same way that if you have a sensory awareness of a chair, you are rationally justified in believing that the chair is there. If I cannot demonstrate to you with empirical evidence that God has revealed something to me, it doesn’t follow that he has not. I can know, and be absolutely certain of, the fact that I ate oatmeal for breakfast this morning, regardless of whether I can provide physical evidence of such. I simply know what I had for breakfast (as a memory, immediate to my awareness). I can be mistaken, but my belief still counts as knowledge. On Reformed epistemology, then, religious beliefs can count as knowledge.
Locke’s unwarranted skepticism about religious beliefs has been quite influential. As Wolterstorff puts it, “The assumed contrast between the epistemic status of natural science and that of religion has not ceased to cast its spell over Western intellectuals in the time between us and Locke.” Locke’s ideas were stepping stones for later philosophers such as Kant and Hume, whose ideas had the effect of separating reason from faith even further. I think we can do better, and we will see how Alvin Plantinga’s Reformed Epistemology offers an alternative way to think about justified religious beliefs in a later post.
 For this essay, I am relying primarily on: Nicholas Wolterstorff, “Locke’s Philosophy of Religion,” in The Cambridge Companion to Locke, ed. by Vere Chappell (Cambridge: Cambridge University Press, 1994), 172–198. And supplementing Wolterstorff with: Nicholas Jolley, “Locke on Faith and Reason,” in The Cambridge Companion to Locke’s ‘Essay Concerning Human Understanding,’ ed. by Lex Newman (Cambridge: Cambridge University Press, 2007), 436–455.
 Wolterstorff 190, emphasis his.
 Ibid., 192.
 Ibid., 194–196. The Locke quotation is on p. 194.
 Ibid., 197.
 Seminal figures in Reformed Epistemology include Alvin Plantinga, Nicholas Wolterstorff and William Alston.
 Wolterstorff, 196.
Interested in reading more by Mark? You can explore his thoughts on learning about godly scholarships through Hebrews, his popular posts on The Fruit of the Spirit in Academia, or all of his literary and theological reflections for ESN.