This article distinguishes between two historical ways of presenting the catchphrase “Once true, always true” (semel verum, semper verum), associated with the twelfth-century logical school of the nominales. Within the Time-Jumping Model, a hypothetical tenseless propositional content (enuntiabile) is treated as the common significate of differently tensed statements, such as “Socrates will die” and “Socrates died,” uttered before and after Socrates’s death. This hypothetical enuntiabile is “always true” thanks to its tenseless nature. By contrast, the Fixed-Present Model preserves the tensed (...) character of enuntiabilia. By revealing an implicit temporal index, the nominales could apply “Once true, always true” to enuntiabilia such as Christum venisse (that Christ has come), which not only is true and will always be true but also – paradoxically – has always been true. It has always been true because it amounts to the propositional content that Christ came before this instant, where “this instant” rigidly denotes the present moment. The Fixed-Present Model alleviates the worry that the nominales confused truth-bearers with truthmakers. (shrink)

This special issue grew out of a small conference The Known & the Unknown: Exploring Twelfth-Century Philosophy, which was funded by the Carlsberg Foundation, hosted by the Saxo Institute, and held at the University of Copenhagen in April 2018. Its central topic was the many, mostly unexplored, commentaries on Aristotle, Boethius, and Porphyry that constitute the key textual evidence for a fascinating phenomenon that, although it played a pivotal role in the philosophical revival of Western Europe, remains frustratingly underexplored to (...) this day: the logical schools of the twelfth century. The present introduction has two parts. In the first part, John Marenbon lays out the background to this special issue of Vivarium as a whole, explaining both what the philosophical project pursued by twelfth-century logicians was and how, and how far, the historical project of understanding it has progressed over the last two hundred years. In the second part, Heine Hansen briefly presents the issue and its contents. (shrink)