The Spanish philosopher Sebastián Izquierdo was a luminary of seventeenth-century scholasticism. In his main philosophical work, Pharus scientiarum, Izquierdo claims to be the first to provide a systematic analysis of the notion of priority. Izquierdo is not the first to attempt an analysis of priority, but his treatment is original and rigorous. Izquierdo distinguishes between accidental and essential priority. This distinction crosscuts his distinction between relative and absolute priority. Izquierdo also recognizes four types of absolute priority: priority of duration, priority of origin, priority of nonmutual connection, and priority of worth. In this article I explain Izquierdo's various priority relations, their formal properties, and how they all cohere in a general theory of priority.

Seventeenth-century Iberian and Italian Scholastics had a concept of a truthmaker (verificativum) similar to that found in contemporary metaphysical debates. I argue that the seventeenth-century notion of a truthmaker can be illuminated by a prevalent seventeenth-century theory of truth according to which the truth of a proposition is the mereological sum of that proposition and its intentional object. I explain this theory of truth and then spell out the account of truthmaking it entails.