The 2D Past

When we translate English sentences into tense logic, we often, to preserve sense, need to retain a past-tensed predicate. So 'Dave has walked' becomes 'WAS Dave walked', rather than 'WAS Dave walks', or 'WAS Dave is walking', where the sentential operator 'WAS' serves merely to restrict the scope of the sentence to times earlier than now. I will build on previous work in Briggs and Forbes (2012; 2019); Forbes (2016); Forbes and Wildman (MS) to show how a two-dimensional framework (as used by e.g. Stalnaker 2004) can make sense of the relationship between a past-tensed predicate, and the present-continuous predicate that used to apply (e.g. 'is walking'). I will argue that such a framework allows us to make sense of the ways in which the past is intrinsically the same as when it was present, but also extrinsically different, due to the change in modal status that some event undergoes by becoming past. I will then use this framework to examine two difficult cases: one where what's true of the past changes retrospectively because of extrinsic properties (e.g. 'Armstrong won the Tour de France' becomes false and 'Armstrong never won the Tour de France' becomes true), and the other where, because of changes in meanings, sentences change from being analytically true to being false (e.g. cheese is non-vegan). My treatment of difficult cases will preserve the claim that the past is intrinsically the same as when it was present, but use a change from potentiality to actuality to explain cases where it seems that the past has changed by becoming past.