Symposium on Time
Monday 5th of September 2016
at “SIFA Biannual Conference”, 5-7 September 2016, Pistoia
Sven Rosenkranz (ICREA, Logos, Barcelona) – “Unfreezing the Spotlight: Tense Realism and Temporal Passage”
Stephan Torre (Aberdeen) – “Present Experience and the Block Universe”
Roberto Ciuni (Padua) – “Plausibility Trees and Future Contingents”
Ciro De Florio, Aldo Frigerio, and Alessandro Giordani (Università Cattolica) – “Omniscience in Light of the Metaphysics of Time”
Things move and change. This truism seems to suggest that the flow of time is real. However, philosophers disagree on whether reality possesses any genuine dynamic feature or whether dynamism is a reducible, if not illusory, aspect of reality. Lately, a series of articles and books have revived a priori and a posteriori arguments for (and against) both positions, and have elaborated new ones. The workshop aims at gathering original contributions to the ongoing debate on the issue.
14:00 – 15:30 Stephan Torre (Aberdeen) – “Present Experience and the Block Universe”
15:30 – 15:50 Coffe break
15:50 – 17:20 Sven Rosenkranz (ICREA, Logos, Barcelona) – “Unfreezing the Spotlight: Tense Realism and Temporal Passage”
—17:20 – 18:00 Ciro De Florio, Aldo Frigerio, and Alessandro Giordani (Università Cattolica) – “Omniscience in Light of the Metaphysics of Time”
18:00 – 18:15 Coffee break
18:15 – 18:55 Roberto Ciuni (Padua) – “Plausibility Trees and Future Contingents”
Roberto Ciuni (Padua) – Plausibility Trees and Future Contingents
Abstract: Since (Prior, 1967), different branching-time semantics have been developed in order to reason about indeterministic future, the main proposals in the area being the Ockhamist and Peircean semantics by (Prior, 1967), the Thin Red Line semantics defended by (Øhrstrøm, 2013), the supervaluationist semantics by (Thomason, 1970), and the so-called postsemantics by (MacFarlane, 2003). The main goal of such proposals is to provide a tool to express (and reason about) the future contingents – that is, sentences of the form ‘It will be the case that φ‘, where φ is neither inevitable nor impossible. Since in branching-time structure every state of the world has many different continuations, assigning a truth-value to future contingents it is not a trivial task, and the proposals above come with four different ways to model simple-future sentences.
This paper has two aims: showing certain limitations the current branching-time semantics have in modeling future contingents, and proposing a new logical setting that overcomes such limitations.
First, I argue that all the current branching-time semantics fail to meet at least one of the following conditions for a theory of future contingents: (1) valuation of future contingents must be moment-relative only, (2) ‘simple future’ must not collapse on ‘necessary future’ or ‘possible future’, (3) later revisions on the truth of future contingents must be possible. The importance of such desiderata is also argued for.
Second, I propose a new logical setting for future contingents, which I call Plausibility Branching-time Logic (PBT, for short). This setting imposes a plausibility ordering over histories in a tree, and interprets ‘It will be the case that φ’ as ‘There is a history h such that for all the histories h’ that are equally or more plausible than h, there is a later moment where it is the case that there is a sea battle’ – the implicit condition here is that we consider histories passing through the moment of valuation. I then show that my proposal meets the three desiderata the current branching-time semantics fail to meet.
Ciro De Florio, Aldo Frigerio, and Alessandro Giordani (Università Cattolica) – Omniscience in Light of the Metaphysics of Time
Abstract: In traditional theism, God is conceived of both as immutable and omniscient. In his seminal (1966) Kretzmann advances an argument that aims at showing that these two attributes are incompatible on the ground that a being that is omniscient must always know what time it is and a being that always knows what time it is is subject to change. Kretzmann’s argument is the topic of the debate between compatibilists, who try to show that the argument is not sound, and incompatibilists, who try to show that the argument cannot be overcome. However, two important aspects are neglected in this debate:
1. Generally, the adopted metaphysics of time is not explicitly characterized by the authors;
2. No authors introduce an epistemic system able to account for the concept of omniscience and the concept of temporal knowledge.
The first aim of this paper is to analyse the problem according to two different metaphysics of time formalized through two logical frameworks; in these frameworks we will show that the arguments of compatibilists and incompatibilists can be developed in a precise and explicit way. The two metaphysics of time we take into consideration for the construction of the epistemic systems are: (i) static eternalism; (ii) the moving spot-light theory. Through our analysis, we can reach a threefold conclusion:
• Within the eternalist model, it is possible to prove the negation of Kretzmann’s thesis: omniscience and immutability are compatible.
• Within the moving spot-light model, it is possible to prove Kretzmann’s result.
• In the end, we argue that it is plausible to assume that God can have a comprehensive sight of every models; so we state that at the meta-theoretic level, there is a plausible sense in which one can say that God’s knowledge is immutable and complete. We sketch a tentative characterization of this meta-model.
Sven Rosenkranz (ICREA, Logos, Barcelona) – Unfreezing the Spotlight: Tense Realism and Temporal Passage
Abstract: The paper argues that realism about tense – i.e. the view that there are genuinely tensed facts – already suffices for realism about temporal passage – contrary to what recent works by Fine and Cameron contend. Throughout, the discussion focuses on the so-called Moving Spotlight Theory. However, it can be shown that the conclusion generalizes to other realist views such as presentism, the so-called Growing Block Theory and Williamson-style permanentism.
Stephan Torre (Aberdeen) – Present Experience and the Block Universe
Abstract: Suppose you are presently staring at a red wall having an experience of redness. Your present experience of redness seems to have certain features that privilege it over past and future experiences. But if the block universe theory is true, all of your experiences, past, present and future, are equally real. Furthermore, you are related to each of them in the same way and to the same degree. This leads to the following challenge: how can the block universe theory explain the fact that your present experience seems privileged over past and future experiences? This paper attempts to isolate the relevant features that present experience has and argues for a new way in which the block universe theorist can accommodate them by appealing to work by Tim Bayne and David Chalmers on the unity of consciousness.