No one believes only what they can prove historically. For example, most of us can remember experiences from years ago that we surely believe happened but that we cannot “prove” to others’ satisfaction without finding corroborating witnesses or documentary evidence. Unless, of course, our very testimony counts as evidence—which, if we are reasonably reliable persons, it normally should, except where counterevidence argues otherwise.
In many disciplines, people of different convictions work together. A Christian herpetologist who attributes life to divine design on any level has a markedly different perspective on life than does an atheist herpetologist. Yet when it comes to details of reptile anatomy, they share mostly common ground.
The humanities tend to be more complicated on a number of levels, but there are some parallels. For example, an atheist and a Christian have vastly different personal approaches to the Bible, but both may use historical methods. Their beliefs will inevitably color the ways they approach the evidence, and even what data they admit as evidence, but there will still be a shared body of common ground or at least common data to work from.
Simply because they work from some common ground, however, does not mean that neither of them has beliefs outside that common ground. Valuable as experimentation is in the scientific sphere, virtually no one actually lives like that is the only method of ascertaining truth personally (taking no one else’s word for anything without testing it empirically). (Admittedly, as a toddler I likely did want to test electrical outlets personally regardless of parental warnings to the contrary.)
Still less does anyone live like only what is verifiable by historical means actually happened. When those within the guild of New Testament scholarship speak of historical probabilities, they speak in terms of what is probable by normal historiographic criteria. But since probabilities are not invariably correct, and because estimates of probabilities are subject to the limited information and criteria considered, it is also probable that they will sometimes be mistaken. Many who use these methods have sufficient epistemic humility to recognize that these methods give us only a basic picture.
On the basis of historiographic methods, scholars often come to very diverse conclusions. This diversity reflects not only the methods but the data that we take into consideration. As in computer language: garbage in, garbage out. I believe that a wider range of data, which I have tried to bring to bear in my recent Christobiography and some other works, suggests that on average most passages in, say, Mark’s Gospel, reflect reliable information about events. Some scholars will disagree, but hopefully they will at least expand their perspective to include the new data I seek to bring to bear on the subject.
I believe that historiography can give us general estimates, but it cannot tell us everything that ever happened. This does not mean that I believe that only what I can demonstrate historically happened. This just means that this is all that I have evidence available to demonstrate. Sometimes those unaccustomed to the way scholars in a discipline talk to one another misunderstand the point.
There is also the question of epistemology. None of us do live like only what we can prove historically happened. In the case of the Gospels, I can argue historically that they tell us a lot about Jesus. I cannot provide historical evidence for every point. But I personally believe that they offer more than enough information about Jesus to invite us to place our trust in him—and therefore accept his verdict on the Scriptures already accepted among his people, and the authorization of his commissioned agents whose message appears in the New Testament.
I also personally believe, as a Christian, that the Spirit attests Scripture. (That was Calvin’s view; it’s also my experience as a charismatic.) To someone who does not experience the Spirit, that sounds utterly subjective; but that is because in that sphere Christians and their detractors have different epistemologies.
Thus I can make a limited historical argument in a scholarly setting that permits only historical arguments, but personally believe more because of what I regard as a complementary epistemology. Skeptics are apt to jump on that observation, but I distinguish between my historical arguments, and consequently what I expect my hearers to accept on the basis of such arguments, from my personal beliefs and experience. I am happy to share the latter, but it is normally persuasive only to those who share my epistemological convictions in those areas.
Not making this distinction can produce problems. For example, someone may assume that what they cannot demonstrate, based on historical grounds apart from the testimony of the text, did not happen. But not demonstrating that something happened is not the same as demonstrating that it did not happen. Likewise, people do not always understand what scholars working within a discipline mean by their language. When a scholar offers a narrower historical argument that suggests that “X probably happened, but evidence for Y is tenuous,” this does not necessarily mean that they do not believe that X and Y happened. It simply means that they do not have much evidence for Y.
The genre of certain kinds of academic work simply takes for granted that scholars are making judgments based on the historical data available. In this genre of writing, one does not intrude with other epistemological approaches such as, “The Holy Spirit tells me this is true!” Usually writers do not even stop to explain that the basis of their considerations suffers from methodological limitations. For example, the testimony in front of us is itself evidence, if it proves generally consistent with the data where we can test it.
If anyone has followed my attempt to make the distinctions thus far, my points are: the genre of academic works related to historiography limits arguments to historiographic grounds. If one has other epistemic reasons to believe something happened (e.g., personal experience of its happening), one has reason to believe more than one has argued for in the academic work. My own experience of the Spirit and what I see as divine activity makes this seem a no-brainer for me. But that does not make it ethical for me to claim historical evidence where I lack that.
Some skeptics complain that my experience of the Spirit and Christian commitments will bias me; of course, I would argue that skeptical approaches can bias skeptics. When we discuss together, we have to do so based on the data in front of us. It is not ethical to make up historical data. At the same time, some other people complain that I should, but do not, defend every detail of Scripture in my academic works. Historical method does not allow us to defend (or dispute) every detail. But I am a Jesus-follower, who does accept the Scripture he accepted and the message and agents that he commissioned. I do trust the Spirit, the Spirit that I experience. So I do believe far more than what I defend historically (and seek to defend historically less than I personally believe). It is a question of appropriate genre and the epistemologies accepted in those genres.