Abstract

Formal semantics constitutes the framework of this thesis, and the aim is to characterise the semantics of the progressive, as it appears in sentence. Max was running towards the station Among the problems is one known as the "imperfective paradox". According to intuitions, sentence entails, but no entailment holds between and. Max was running towards the station Max ran towards the station Max was running to the station Max ran to the station Since and would seem to have the same logical form, they ought to have similar entailments. Why is this not so? This thesis is divided into two parts. The first part, containing chapters 2 to 5, evaluates the current formal theories that tackle the imperfective paradox. Solving the imperfective paradox consists of two tasks: the first is to characterise a semantic distinction between and, and the second is to supply a semantic analysis of the progressive that is sensitive to this distinction and so results in a solution to the imperfective paradox. According to how the current theories tackle these two tasks, they can be classified into three camps which I will name as follows: the Heterogeneous Strategy provides one approach for fulfilling the first task, the Eventual Outcome Strategy provides an approach for defining the semantics of the progressive, and the Event-based Strategy provides a further alternative for achieving the two tasks at hand. All these strategies are intuitively motivated, but we will argue that they are ultimately untenable. The Heterogeneous Strategy and the Event-based Strategy fail to mesh with the treatment of point adverbials such as "At 3pm", and the Eventual Outcome Strategy produces a definition of the progressive that is viciously circular. Thus although the current theories that tackle the imperfective paradox are highly intuitively motivated, we will ultimately show that the formulations of these intuitions give rise to conflicts and tensions when it comes to explaining the natural language data. The second part of the thesis, containing chapters 6 and 7, offers a new approach for tackling the imperfective paradox. This new approach invokes two tools; the interval-based temporal logic IQ, and Moens' event-based AI model of temporal reference. IQ is an interval-based temporal logic with several innovations. First, unlike the previous interval-based theories, IQ maintains a high level of homogeneity: an atomic sentence is true at an interval I only if it is true at all subintervals of I. Second, IQ offers a technique whereby temporal expressions can have representations that receive their semantic interpretation with respect to context. We use the roles of homogeneity and context in IQ to characterise the semantics of aspect, where the characterisation is based on Moens' model. This provides an arena in which to tackle the imperfective paradox anew. We explain the entailment between and, and at the same time explain why no entailment holds between and. Furthermore, we overcome the problems concerning the treatment of adverbials such as "At 3pm" that are encountered in the Heterogeneous Strategy and the Event-based Strategy, and, since we do not adopt the Eventual Outcome Strategy in defining the progressive, we overcome that strategy's problem of circularity. Hence our solution to the imperfective paradox will provide answers to the puzzles posed in the earlier chapters of the thesis.