This dissertation is an investigation of presentism, the thesis that all and only present things exist. Though an increasingly popular topic, it is ill-understood. The investigation has three main aims. Firstly, to improve understanding of the presentist thesis by distinguishing, outlining, and exploring various plausible competing interpretations ('theories'). Secondly, to motivate presentism and weigh-up competing presentist theories against theory-choice criteria. Thirdly, to develop and defend a preferred, and novel, presentist variant: Effervescent Presentism.
What the presentist thesis amounts to depends on how key concepts employed in its statement are interpreted; distinct interpretations each specify competing description of temporal reality. Specifically, the focus is on how we understand existence and the A-determinations—presentness, together with its related notions of pastness and futurity.
The dissertation divides into three parts. In Part One, I establish a fixed, tensed, conception of existence avoiding the triviality charge against presentism, and permitting a robust distinction between mere temporal variation and metaphysical change. Then, having outlined a broadly pragmatic methodology, I provide some motivations for presentism, focusing on its explanatory virtues for the nature of causation. This justifies interest in the project, but also establishes a distinguishing criterion for presentist theories: how well they support those motivations.
In Part Two, I outline alternative presentist theories, and introduce potential theory-choice criteria to suggest plausible interpretative directions and preferentially distinguish theories. Part Three then introduces, develops, and defends effervescent presentism, in greater detail due to its preference and complexity. It delivers an understanding of presentness in terms of a law-based account of causal activity. This ties time intimately to causation, and consequently supports the presentist motivations from Part One and the need to unify time. The research should demonstrate the tenability of effervescent presentism, and its worthiness of wider consideration.
