Quintilian, and J.S. Watson. Institutes of Oratory. Edited by Lee Honeycutt, 2010. Kindle Electronic Edition. Book 7 Chapter 8.
In cases of law, Quintilian brings up the issue of syllogism. In effect, the syllogism is a move beyond the letter of a law (Quintilian VII.8.1). In essence, it shows, using reason, the application of a law to an event or action (Quintilian VII.8.3). The question at issue is often whether a law can be applied. “In such cases, the questions are, whether, when there is not a particular law for a case, we must have recourse to a similar law; and whether the matter in question is similar to that to which the letter of the law refers” (Quintilian VII.8.7).