| This dissertation develops a mental space approach to tense, and tense-aspect as a system, investigating tense phenomena in discourse, in narrative, in embedded clauses, in indirect speech, in conditional constructions, in pragmatic context and in "decontextualized" sentences.;I propose characterizations of a set of putatively universal discourse construction notions: ;A central claim of the dissertation is that tense plays a fundamental role in the management and organization of discourse and in the cognitive construction process. Tense-aspect categories give instructions concerning: the construction and organization of spaces; the organization and distribution of the discourse primitives ;The special access properties of spaces constructed for indirect speech and conditional constructions are investigated. I propose a FACT/PREDICTION Principle which limits access from V-POINT/BASE, imposing a kind of viewpoint consistency on indirect speech in terms of a space's FACT/PREDICTION status. I argue that PAST hypothetical and counterfactual conditional constructions have different embedding structures. For counterfactual apodoses, only certain types of access paths can be embedded in the counterfactual domain. I also show that: tense may anchor to a non-BASE V-POINT; a space may be accessed and reaccessed via different access paths; and narrative may be set up with various levels of reference, each with its own V-POINT/BASE from which tense is accessed. |