Aspect in Ancient Greek - Nijmegen Centre for Semantics

140 Chapter 6. The temporal structure of discourseplenty of examples that deviate from the common patterns. This flexibility,however, should not be captured in terms of a flexible semantics for the aoristand imperfective itself. Their semantics should remain constant throughoutthe examples. In the next section we will see that an anaphoric account of thetopic time ensures the flexibility needed.6.3 Analysing the patterns6.3.1 Determining the topic timeThe account I propose in order to explain the temporal patterns described inthe previous section consists of the following two components:1. the by now familiar semantics of aoristic and imperfective aspect: theaorist contributes the information that the time of the eventuality isincluded in the topic time (τ(e) ⊆ t TT ), the imperfective that the topictime is a non-final subset of the time of the eventuality (τ(e) ·⊃ t TT );2. the default rules of how the topic time of a sentence is determined by itscontext. Let’s number the sentences in a discourse 1 ... n and let thesentence we interpret be i. Then t TTi , the topic time of sentence i, is bydefault:(a) a time immediately following the eventuality time of the previoussentence τ(e) i−1 if that sentence has aoristic aspect: τ(e) i−1 ⊃≺t TTi ;(b) the topic time of the previous sentence, t TTi−1 , if that sentence hasimperfective aspect: t TTi−1 = t TTi .In section 6.3.3 I will show how these rules yield the patterns found. But firstI will show how I implement these rules in a so-called pushing account andexplain why a prefer such an account over a pulling account.6.3.2 Pushing versus pullingMore often than not the time about which the speaker makes his utteranceis recoverable from the context in which the sentence is used. I model thisby treating this time, the topic time, as an anaphor: it binds to a time that