Quintilian, and J.S. Watson. Institutes of Oratory.Edited by Lee Honeycutt, 2010. Kindle Electronic Edition. Book VII Chapter 2.
In book VII chapter two Quintilian deals with conjecture. “All conjecture has reference either to fact or intent” (Quintilian VII.2.1). To make a reasoned estimate, time is an important factor. The issue of generality and specificity is also important. Quintilian discusses the distinction between intention and chance, as well as the basic decision of whether something actually exists or has happened (Quintilian VII.2.3). As to time, if a person was not in a location necessary at the time of an event, the crime was not committed by that person. Establishing times and locations is very important (Quintilian VII.2.4). In court cases, conjecture is central. Questioning all facets is therefore important (Quintilian VII.2.8). Questions of motive and opportunity are closely related (Quintilian VII.2.10). Quintilian goes on to illustrate the kind of inquiry which may happen in court. One of the central questions is whether a crime, once established, could have been committed by only one person (Quintilian VII.2.16). Comparison of claims of innocence or accusations of guilt is a form of conjecture which is often needed in court cases (Quintilian VII.2.22). Another type of case requiring conjecture involves a claim for reward or blame. The claimants are weighed to see whose claim is more valid (Quintilian VII.2.25).
“The order in which we have to consider evidence as to any act is whether the accused had the will to do it, had the power to do it, and whether he actually did it” (Quintilian VII.2.27). The first consideration becomes “the character of the accused” (Quintilian VII.2.28). Next is an investigation of motive. Without motive a person will not act (Quintilian VII.2.35). The case for intentionality may also be considered along with the motive. the level of premeditation and intention is often important in consideration of penalty (Quintilian VII.2.42). Other considerations of ability are also important, such as time, location, and the like (Quintilian VII.2.44). Finally, even if the person could have committed a crime he may or may not have done so. Consideration of the actual guilt does depend on this (Quintilian VII.2.46).