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The Imperfect Present: Stoic Physics of Time


This dissertation addresses a set of problems in understanding the Stoic physics of time. It begins by investigating the ontology of time as an incorporeal in Stoic physics. I show that time is constructed as a deliberate parallel to two of the other incorporeals – place and void. Time is defined as the “diastēma” of motion, and much of the debate over the Stoic theory of time has centered on the definition of this term “diastēma,” which may mean interval, extension, or dimension. I argue that only the reading of “dimension” makes sense in the context of Stoic physics. Place turns out to have three dimensions, measuring the height, depth, and breadth of bodies, while time adds a fourth dimension of motion that measures fast and slow of bodies in motion.

The second half of the dissertation addresses the vexed problem of the present in Stoicism. Multiple sources tell us that the present has a different status from the past and future – the past and future merely “subsist” while the present “is real.” However, this account is complicated by strong evidence that the Stoic present is composed of past and future. Furthermore, Stoic accounts of divisibility leave the length of the present apparently indefinite. If the present is ontologically privileged, it seems that it cannot be of indefinite length. If the present is real but the past and future are not, it seems that the present cannot be composed of past and future.

I resolve these problems by arguing that the Stoics had two interrelated definitions of the present, and that the apparently conflicting pieces of evidence refer to different kinds of present. The first present is called “precise” or “narrow” and corresponds to a point of zero duration. As it has no duration, it is not a continuum, and as it is not a continuum it is not, technically, a time. A secondary “broad” present, composed of past and future times, is present in virtue of containing this present. It derives a special ontology from its relationship to the strict present, despite being composed of past and future.

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