Christian Texts and History • Myles Lavan: Epistemic Uncertainty, Subjective Probability, and Ancient History

The uncertainties that historians face are clearly epistemic. They can be represented as probabilities, but only if the probabilities are understood as subjective. A probability is meaningful only in relation to a particular state of knowledge. It represents a historian’s degree of belief based on a body of evidence, not an objective randomness. Hence, this research note speaks of assigning not estimating probabilities and employs the term beliefs to foreground the subjectivity that is inherent in the encounter with uncertainty. According to this view, beliefs comprise a set of evidence-based probabilistic judgments about historical uncertainties. “Your” beliefs about the past may differ from “mine” if “you” have access to more (or less) information than “I” have or if “you” interpret it differently. But describing beliefs in terms of probabilities clarifies our differences and facilitates dialectic.

The avowedly subjective character of the framework may trouble some historians. But it merely makes explicit an inherent feature of historical analysis. Historians can present their evidence and their arguments, but they can never coerce their colleagues’ assent; other scholars may reach different conclusions from the same evidence. The most that they can hope is that their reasoning will prove persuasive. This condition is no different from my expectation that other scholars will recognize in my probability distributions a careful and honest representation of the state of knowledge. The subjectivity inherent in historical analysis is too often regarded as an intellectual defect to be obfuscated through a misleading rhetoric of objective authority. One of the great merits of this framework is that it acknowledges the irreducible subjectivity in all empirical disciplines and shows that it is not an obstacle to quantitative analysis.