Argument from silence

To make an argument from silence (Latin: argumentum ex silentio) is to express a conclusion that is based on the absence of statements in historical documents, rather than their presence. In the field of classical studies, it often refers to the assertion that an author is ignorant of a subject, based on the lack of references to it in the author's available writings. Thus, in historical analysis with an argument from silence, the absence of a reference to an event or a document is used to cast doubt on the event not mentioned. While most historical approaches rely on what an author's works contain, an argument from silence relies on what the book or document does not contain. This approach thus uses what an author "should have said" rather than what is available in the author's extant writings.

An argument from silence may apply to a document only if the author was expected to have the information, was intending to give a complete account of the situation, and the item was important enough and interesting enough to deserve to be mentioned at the time. Arguments from silence, based on a writer's failure to mention an event, are distinct from arguments from ignorance which rely on a total "absence of evidence" and are widely considered unreliable; however arguments from silence themselves are also generally viewed as rather weak in many cases; or considered as fallacies.

John Lange provided the basic structure for the analysis of arguments from silence based on three components:

The applicability of these three conditions is decided on a case-by-case basis, and there are no general dialectical rules for them, except the historian's expertise in evaluating the situation. In Lange's analysis, an argument from silence is only suggestive and never logically conclusive.

Professors of history Martha Howell and Walter Prevenier thus state that an argument from silence can act as presumptive evidence only if the person failing to mention the information was in a position to have the information, and was purporting to be giving a complete account of the story in question. Howell and Prevenier state that arguments from silence face the difficulty that a historian can not just assume that an author would have recorded the fact in question; for if the fact did not seem important enough to an author it would have been excluded.

Professor of English Michael Duncan states that there are very few scholarly analyses of arguments from silence; but these typically view it as fallacious. Duncan adds that arguments from silence are not mentioned in Aristotle's Sophistical Refutations or Hamblin's book Fallacies, but both of these texts discuss the somewhat similar case of argument from ignorance. Errietta Bissa, professor of Classics at University of Wales, flatly states that arguments from silence are not valid. David Henige states that, although risky, such arguments can at times shed light on historical events.

The importance of an event to a contemporary author plays a role in the decision to mention it, and historian Krishnaji Chitnis states that for an argument from silence to apply, it must be of interest and significance to the person expected to be recording it, else it may be ignored; e.g. while later historians have lauded Magna Carta as a great national document, contemporary authors did not even record a word about its greatness; to them it was a feudal document of low significance, among several other seemingly similar items.

Classicist Timothy Barnes notes that the low level of interest in and awareness of Christians within the Roman Empire at the turn of the first century resulted in the lack of any discernible mention of them by Roman authors such as Martial and Juvenal, although Christians had been present in Rome since the reign of Claudius (41 to 54 AD) and both authors referred to Judaism. Theologian Peter Lampe states that during the first two centuries, the silence of Roman sources on Christians in Rome may be partly due to the fact that Christians often kept to themselves and did not reveal their identities.