The Oracle at Delphi: Unknowability at the Heart of the Ancient Greek World

history has been famously described as just one damn thing after another—an endless list of events. Yet, of course, to define history as such would be to sell it very short indeed. The canvas of our human past is vast, varied, and complex, existing in an infinite number of simultaneous events, a similar number of perceptions and interpretations of those events, and a wide range of reactions and decisions emerging from them. In response to such a vast canvas of inquiry, historians have prioritized: not all unknowns, it turns out, are created equal. The study of history has thus coalesced traditionally around two types of unknown. Not "known and unknown" unknowns, but rather, "unknowns we would like to know," and "unknowns we don't currently think it important to know."

These two categories of unknown have dealt with unknowability in very different ways. In relation to the first category—unknowns we would like to know—I would argue that historical study has traditionally left little room for unknowability. This is essentially because the process of writing history allows for the creation of authoritative visions of the past in many ways independent of the degree to which the past is known or unknown, and independent of the degree to which that vision is provable in any scientific sense.

On any given topic, the historian consults evidence surviving from a range of different types of primary sources and tries to form a picture of what happened, how those events were understood, and their consequences. To do so crucially involves the active judgment of the historian in weighing up a range of sources: some will be closer to the topic in question, either geographically or temporally; others will perhaps be given greater weight as more authoritative based on who produced them or due to the source material through which they have survived. Rarely are all those decisions clear-cut—and thus, often each historian, exercising their judgment on what sources they choose to listen to and prioritize, will create a different picture of the past based on the same set of sources.

There is, however, almost never sufficient primary evidence to fill the gap of the unknown completely. The historian then turns to creating an argument, a vision, for how they think we should fill in the gaps, perhaps by comparing the topic in question to a similar period, event, or idea elsewhere in time and space. Most often, they do this in conjunction with the visions produced by previous scholars working in the field (the "secondary scholarship")—offering arguments as to why they agree with some and not with others, expanding or reworking aspects of previous visions, to produce what they feel to be the most compelling version of events.

These versions of events, these visions of the past, cannot be subjected to any kind of scientific process of proof because they are based on arguments, suppositions, and ideas about a topic that is only known about through a patchwork of often uncertain sources. Instead, historians' visions for how we should understand the past acquire their authority through a process of debate, judgment, and acceptance by the general historical community based on what is considered most reasonable and convincing. Visions may be discarded as less convincing than previous attempts to fill the gap, or they may be accepted, replacing those previous visions of the topic. Or they might find their place alongside a number of visions for how we should understand that topic, each of which is favored by different collections of historians for a variety of different reasons. And so the process goes on—without any necessary end. A historian's vision for an aspect of the unknown in our past only stands for as long as it is not successfully challenged. As the saying goes, "only the future is certain, the past just keeps on changing."

As such, we need to acknowledge that in writing the story of the past, and in accepting particular visions of it, historians are not only creating, challenging, and agreeing with visions...