Sven Rosenkranz

Eternal Facts in an Ageing Universe

In recent publications, Kit Fine devises a classification of A-theories of time and defends a non-standard A-theory he calls fragmentalism, according to which reality as a whole is incoherent but fragments into classes of mutually coherent tensed facts. We argue that Fines classification in not exhaustive, as it ignores another non-standard A-theory we dub dynamic absolutism, according to which there are tensed facts that stay numerically the same and yet undergo qualitative changes as time goes by. We expound this theory in some detail and argue that it is a serious alternative to the positions identified by Fine.

Determinism, the Open Future and Branching Time

In this chapter, I argue that on a natural understanding of both views, indeterminism and branching time are incompatible, contrary to what recent literature on the open future suggests. In the first section, I introduce two notions of truth-determination that importantly differ from the notion of truth-making. In the second section, I use these notions to devise a definition of determinism that captures the central idea that, given the past and present, the future cannot but be a certain way. Indeterminism is then defined in opposition to determinism in the third section. In the fourth section, I argue that the tree-like representation of future possibilities is not suggestive of branching time and that indeterminism is perfectly consistent with assumption of a Thin Red Line, that is, a unique way things will turn out to be, a claim shown to be unthreatened by considerations concerning human freedom. In the fifth section, I argue that taking branching time seriously implies commitment to determinism. In the sixth section, I consider a recent attempt to capture the open future and show that it is naturally seen to draw on a conception of the determinately true as what is determined to be true in the second of the senses introduced in the first section. In the seventh section, I argue that the authors’ suggestion that determinism is nonetheless consistent with admission of a multitude of future possibilities is at best unmotivated and at worst misguided. Section eight summarises the results.

The Growing Block

In this chapter we reconstruct the original version of the Growing Block Theory of time first advanced by C. D. Broad, highlight its shortcomings, and propose an improved version of the theory. We show that this improved version of the theory is superior to two more recent attempts to capture the idea of the growing block. In Sect. 4.1 we critically review central passages from Broad’s Scientific Thought, identify core principles that give substance to the image of a growing block, delimited by an edge of becoming beyond which nothing exists, and diagnose a number of problems with Broad’s account. In Sect. 4.2 we then present a neater version of the theory that still incorporates central ideas of Broad’s, yet avoids those problems. In Sect 4.3 we critically review the accounts respectively advanced by M. Tooley and T. Button and conclude that our version of the theory fares much better.

The Other Contenders

In this chapter we offer novel characterisations of presentism and permanentism which, or so we argue, significantly improve upon extant accounts. In particular, we show that, given the availability of these characterisations, neither presentism nor dynamic permanentism needs to invoke any substantial notion of presentness. In Sect. 5.1 we rehearse T. Williamson’s misgivings about the use of the notion of presentness in attempts to articulate presentism. While Williamson takes these misgivings to be sufficient to discard presentism, in Sect. 5.2 we show that the view allows for its systematic reformulation solely in terms of tensed quantification, temporal operators and a predicate for times. In Sect. 5.3, after giving a characterisation of static permanentism and critically discussing R. Cameron’s recent account of the Moving Spotlight Theory, we offer an equally lean formulation of dynamic permanentism solely in terms of temporal operators and a tensed proposition true at one time only.

Taking Tense Seriously

In this chapter we introduce the system of propositional tense logic that we will use throughout the book, clarify what it means to take tense seriously for the purposes of metaphysical enquiry, and clarify the contrast between dynamic and static conceptions of reality. In Sect. 1.1 we set out Arthur Prior’s operator approach to tense and distinguish between the grammatical and the logical notions of tense, which latter calls for a systematic regimentation of ordinary language. In Sect. 1.2 we present axioms governing non-metric temporal operators, including non-standard operators of the form ‘At t’. In Sect. 1.3 we use the notion of truth simpliciter to discern two broad types of metaphysical views that disagree on whether a complete description of reality requires the use of tense.

Existence, Quantification and Identity

In this chapter we introduce the distinction between permanentist and temporaryist ontologies and present a non-classical theory of unrestricted quantification and identity that is compatible with either type of view. We discuss and defuse a recent objection that temporaryism cannot accommodate unrestricted quantification. In Sect. 2.1 we use temporal operators and quantification in order to articulate the core tenets of permanentism and temporaryism, and show that static conceptions of reality are committed to permanentism. In Sect. 2.2 we observe that classical quantification theory favours permanentism, and for reasons of neutrality, replace it by a quantification theory that, jointly with corresponding axioms for identity, yields a positive free logic. In Sect. 2.3 we reject T. Williamson’s argument meant to show that temporaryists should endorse the so-called temporal being constraint, lest they be accused of using restricted quantification when articulating their view.

Classical Theories of Time, and Relativity

In this chapter we explicate the challenge posed to classical theories of time by relativistic physics, and show that two recent attempts to reconcile such theories with Special and General Relativity founder. We conclude that a systematic revision of the classical theories is called for. In Sect. 8.1 we argue that the challenge is best conceived as threatening the intelligibility of the postulate, common to all classical theories, that there is an absolute and total temporal order. We show that C. Bourne’s appeal to primitive tenses is insufficient to avert the challenge. In Sect. 8.2 we scrutinize D. Zimmerman’s recent attempt to construe the postulated temporal order as being imposed by the contents of spacetime rather than its structure. We argue that this attempt fails to answer the challenge, and conclude in Sect. 8.3 that metaphysicians should move on and devise successor theories that no longer postulate such an order.

The Epistemic Objection

In this chapter we critically discuss the so-called epistemic objection against the Growing Block Theory of time and argue that it rests on flawed conceptions of tense and of the import of the theory’s main tenets. We show how the theory enables knowledge of the location of the edge of reality that it posits. After introducing the epistemic objection as it figures in the extant literature, we argue in Sect. 6.1 and Sect. 6.2 that this objection either rests on a gross misunderstanding of the theory’s conception of the past, or else on a gross misunderstanding of the way in which utterances, or judgements, with tensed contents are evaluated for truth and falsity. In Sect. 6.3 we provide a constructive response to the remaining challenge, viz. to show how we might know that we are not in the past of the growing block’s edge of becoming.

Bivalence, Future Contingents and the Open Future

In this chapter we critically discuss the objection that since truths require grounds, the Growing Block Theory must take bivalence to fail for future contingents, while it proves at odds with the best account of such a failure. We challenge the version of the grounding requirement driving this objection, devise a better formulation, and show that the theory can retain bivalence and accommodate an interesting form of indeterminism. After rehearsing the objection in Sect. 7.1, in Sect. 7.2 we review different ways to articulate the grounding requirement, conclude that it should suffice that, for any tensed truth, sometimes there be grounds for it, and show how this requirement can be met by contingent truths about the future. In Sect. 7.3 we explicate a conception of the asymmetry between the open future and the fixed past, consistent with bivalence and available to the Growing Block Theory but none of its rivals.

Peer Disagreement: A Call for the Revision of Prior Probabilities

The current debate about peer disagreement has so far mainly focused on the question of whether peer disagreements provide genuine counterevidence to which we should respond by revising our credences. By contrast, comparatively little attention has been devoted to the question by which process, if any, such revision should be brought about. The standard assumption is that we update our credences by conditionalizing on the evidence that peer disagreements provide. In this paper, we argue that non-dogmatist views have good reasons to reject conditionalization. Instead, peer disagreements should be understood to call for a revision of our prior conditional probabilities: rather than merely adding to our original evidence, they pose a challenge to the thought that we have properly assessed the probative force of our original evidence.