ILLC 25th Anniversary


Abstract Blackburn


Arthur Prior and 'Now'

Patrick Blackburn (Roskilde University)

On the 4th of December 1967, Hans Kamp sent his UCLA seminar notes on the logic of ‘now’ to Arthur Prior. Kamp’s two-dimensional analysis of 'now' led Prior to an intense burst of creativity in which he sought to integrate Kamp’s work into an orthodox one-dimensional framework. Prior's search led him through the philosophy of Castañeda, and back to his earlier work on hybrid logic; the first made temporal reference philosophically respectable, the second made it technically feasible.

Prior's six-week quest offers a fascinating glimpse into the early history of tense logic. By drawing on material from the Prior archive in the Bodleian library, and the paper “ ‘Now’ ” that detailed Prior's findings, I'll retell the story from a contemporary perspective. The story I'll tell
is the result of joint work with Klaus Frovin Jørgensen.