Where have all the Californian tense-logicians gone?

Arthur N. Prior, in the Preface of Past, Present and Future, made clear his indebtedness to “the very lively tense-logicians of California for many discussions”. Strangely, with a notable exception of Copeland (1996), there is no extensive discussion of these scholars (as a group, if not a school) in the literature on the history of tense logic. In this paper, I propose to study how Nino B. Cocchiarella, as a foremost Californian tense-logician, interacted with Prior in the late 1960s. By gathering clues from their correspondence available at Virtual Lab for Prior Studies, I will highlight some of the differences between their views on tense-logic, which might still have far-reaching philosophical implications. I will conclude with a sketch of how to study in what ways Prior and Cocchiarella influenced some other Californian tense-logicians.