The aims of this paper are: (1) to present tense-logical versions of such classical notions as saturated and special models; (2) to establish several fundamental existence theorems about these notions; (3) to apply these powerful techniques to tense complexity.In this paper we are concerned exclusively with quantifiedK 1 (for linear time) with constant domain. Our present research owes much to Bowen [2], Fine [5] and Gabbay [6].

A view of individuals as constituted of quantities of matter, both understood as continuants enduring over time, is elaborated in some detail. Constitution is a three-place relation which can't be collapsed to identity because of the place-holder for a time and because individuals and quantities of matter have such a radically different character. Individuals are transient entities with limited lifetimes, whereas quantities are permanent existents undergoing change in physical and chemical properties from time to time. Coincidence, considered as a matter (...) of occupying the same place, is developed, alongside sameness of constitutive matter, as a criterion of identity for individuals. Quantities satisfy the mereological criterion of identity, applicable to entities subject to mereological relations and operations such as regions of space and intervals of time. A time-dependent analogue of mereological parthood is defined for individuals, in terms of which analogues of the other mereological relations can be defined. But it is argued that there is no analogue of the mereological operation of summation for individuals. (shrink)

Frege taught us how to understand one form of predication: an atemporal one. There is also a different, temporal form of predication, which I briefly introduce. Accordingly, there are two fundamentally different approaches to time: a reductive one, aiming to account for time in terms of Frege’s atemporal predication, and a non-reductive one, insisting that the temporal form of predication is sui generis, and that time is to be understood in its terms. I do not directly argue for or against (...) reductionism in this paper. Rather, by evaluating the debates on endurantism–perdurantism, A-theory–B-theory, and presentism–eternalism, I argue that these debates, although aiming to be fundamental, largely boil down to mere quarrels between alternative reductive approaches. We should take notice of this fact and reorient ourselves within the debate on time accordingly: the real issue is whether we should reduce or not. I briefly sketch in what sense endurantism, A-theory, and presentism may be developed on a properly anti-reductionist basis. (shrink)

This paper aims at bringing together two debates in metaphysics that so far have been kept separate: the debate about determinism vs. indeterminism as de re modality on the one hand, and the debate about persistence on the other hand. Both debates significantly involve talk of things. We will show that working out a proper semantics for singular terms and an accompanying theory of things, motivated by considerations of quantified modal logic, can significantly further the persistence debate. We will use (...) our semantic framework to give an argument in support of the endurantist position as the best theory of persistence. (shrink)

The article puts forward a branching-style framework for the analysis of determinism and indeterminism of scientific theories, starting from the core idea that an indeterministic system is one whose present allows for more than one alternative possible future. We describe how a definition of determinism stated in terms of branching models supplements and improves current treatments of determinism of theories of physics. In these treatments, we identify three main approaches: one based on the study of equations, one based on mappings (...) between temporal realizations, and one based on branching models. We first give an overview of these approaches and show that current orthodoxy advocates a combination of the mapping- and the equations-based approaches. After giving a detailed formal explication of a branching-based definition of determinism, we consider three concrete applications and end with a formal comparison of the branching- and the mapping-based approach. We conclude that the branching-based definition of determinism most usefully combines formal clarity, connection with an underlying philosophical notion of determinism, and relevance for the practical assessment of theories. 1 Introduction2 Determinism in Philosophy of Science: Three Approaches2.1 Determinism: The core idea and how to spell it out2.2 The three approaches in more detail2.3 Representing indeterminism3 Orthodoxy: DMAP, with Invocations of DEQN4 Branching-Style Determinism 4.1 Models and realizations4.2 Faithfulness4.3 Two types of branching topologies 5 Comparing the Approaches5.1 Case studies5.2 Formal comparison of the DMAP and DBRN frameworks6 Conclusions. (shrink)

Branching theories are popular frameworks for modeling objective indeterminism in the form of a future of open possibilities. In such theories, the notion of a history plays a crucial role: it is both a basic ingredient in the axiomatic definition of the framework, and it is used as a parameter of truth in semantics for languages with a future tense. Furthermore, histories—complete possible courses of events—ground the notion of modal consistency: a set of events is modally consistent iff there is (...) a history containing that set. We will explain these roles of histories and highlight some critical aspects having to do with the fact that histories are global and, in a relevant sense, “big” objects. The notion of modal consistency, on the other hand, has both local and global aspects. We ask in how far a local notion of modal consistency can serve as an alternative to the common uses of histories, and work out two recent approaches to alternatives to histories. Combining these approaches, we develop a novel semantics for branching time. (shrink)

The logical theory of branching space-times, which provides a relativistic framework for studying objective indeterminism, remains mostly disconnected from discussions of space-time theories in philosophy of physics. Earman has criticized the branching approach and suggested “pruning some branches from branching space-time.” This article identifies the different—order-theoretic versus topological—perspective of both discussions as a reason for certain misunderstandings and tries to remove them. Most important, we give a novel, topological criterion of modal consistency that usefully generalizes an earlier criterion, and we (...) introduce a differential-geometrical version of branching space-times as a non-Hausdorff (generalized) manifold. (shrink)

The paper re-evaluates Prior's tenets about indeterminism and relativity from the point of view of the current state of the debate. We first discuss Prior's claims about indeterministic tense logic and about relativity separately and confront them with new technical developments. Then we combine the two topics in a discussion of indeterministic approaches to space-time logics. Finally we show why Prior would not have to "dig his heels in" when it comes to relativity: We point out a way of combining (...) the existential import of the distinction between past, present, and future with a frame-relative notion of the present. (shrink)

This paper aims to clarify the connection between the logic of temporal distinctions and the temporal features of propositions. Contra Prior, it argues that the adoption of tense operators does not commit one to the view that propositions can change their truth value over time.

This article surveys some of the key issues that arise when one tries to use tense logic as a metaphysical theory of the nature of time. Topics discussed include basic tense logic, tense logic and verb tense, the structure of the time series, instants of time, quantified tense logic, and the expressive resources of tense logic.

There are two intuitions about time. The first is that there's something special about the present that objectively differentiates it from the past and the future. Call this intuition Specialness. The second is that the time at which we happen to live is just one among many other times, all of which are ‘on a par’ when it comes to their forming part of reality. Call this other intuition Egalitarianism. Tradition has it that the so-called ‘A-theories of time’ fare well (...) at addressing the first intuition, but rather badly when it comes to the second. The goal of this article is to offer advice to A-theorists about how to reconcile their view with Egalitarianism. (shrink)

Much previous work in artificial intelligence has neglected representing time in all its complexity. In particular, it has neglected continuous change and the indeterminacy of the future. To rectify this, I have developed a first‐order temporal logic, in which it is possible to name and prove things about facts, events, plans, and world histories. In particular, the logic provides analyses of causality, continuous change in quantities, the persistence of facts (the frame problem), and the relationship between tasks and actions. It (...) may be possible to implement a temporal‐inference machine based on this logic, which keeps track of several “maps” of a time line, one per possible history. (shrink)

Propositional contingentism is the view that what propositions there are is a contingent matter—certain propositions ontologically depend on objects which themselves only contingently exist. Possible worlds are, loosely, complete ways the world could have been. That is to say, the ways in which everything in its totality could have been. Propositional contingentists make use of possible worlds frequently. However, a neglected, but important, question concerns whether there are any notions of worlds which are both theoretically adequate and consistent with propositional (...) contingentism. Some notion of a possible world is adequate if the systematic connection between, at least, possibility and truth at some possible world holds. Here, I argue that no adequate notion of a possible world is available to at least those who subscribe to one natural formulation of propositional contingentism. I also show that this result contrasts with a simple and adequate definition of a possible world available to the necessitist—those who hold that necessarily everything necessarily exists. (shrink)

Until is a notoriously difficult temporal operator as it is both existential and universal at the same time: A∪B holds at the current time instant w iff either B holds at w or there exists a time instant w' in the future at which B holds and such that A holds in all the time instants between the current one and ẃ. This “ambivalent” nature poses a significant challenge when attempting to give deduction rules for until. In this paper, in (...) contrast, we make explicit this duality of until by introducing a new temporal operator ∇ that allows us to formalize the “history” of until, i.e., the “internal” universal quantification over the time instants between the current one and ẃ. This approach provides the basis for formalizing deduction systems for temporal logics endowed with the until operator. For concreteness, we give here a labeled natural deduction system N(LTL∇) for a linear-time logic LTL∇ endowed with the new history operator. We show that LTL∇ is equivalent to the linear temporal logic LTL with until, which follows by formalizing back and forth translations between the two logics. We also define an indirect translation from LTL∇ into LTL via temporal logics with past operators; such a result provides an upper bound to the problem of satisfiability for LTL∇ formulas. (shrink)

I argue that time travel to the past is impossible, given a certain metaphysical theory, namely, The Dynamic Theory of Time. I first spell out my particular way of capturing the difference between The Dynamic Theory of Time and its rival, The Static Theory of Time. Next I offer four different arguments for the conclusion that The Dynamic Theory is inconsistent with the possibility of time travel to the past. Then I argue that, even if I am wrong about this, (...) it will still be true that The Dynamic Theory entails that you should not want to travel back to the past. Finally, I conclude by considering a puzzle that arises for those who believe that time travel to the past is metaphysically impossible: What exactly are we thinking about when we seem to be thinking about traveling back in time? For it certainly does not feel like we are thinking about something that is metaphysically impossible. (shrink)

“The Craft of Formal Logic” is Arthur Prior’s unpublished textbook, written in 1950–51, in which he developed a theory of modality as quantification over possible worlds-like objects. This theory predates most of the prominent pioneering texts in possible worlds semantics and anticipates the significance of its basic concept in modal logic. Prior explicitly defines modal operators as quantifiers of ‘entities’ with modal character. Although he talks about these ‘entities’ only informally, and hesitates how to name them, using alternately the phrases (...) ‘possible states of affairs’, ‘chances’, ‘cases’ or ‘peculiar objects’, he is nevertheless very clear that they should be the fundamental concept of any theory of modality as a form of quantity. Without the assumption that modal operators quantify over such modal objects, the modal system will be incapable of distinguishing an actually true proposition from a necessarily true one. Due to the fact that Prior never made any direct reference to this theory in his subsequently published papers, it remained largely unknown. The comparison of “The Craft” with some of his papers on tense logic suggests that this early theory of modality underlies his later work on temporality. (shrink)

Since the early part of this century there has been a considerable amount of discussion of the question 'Does time pass?'. A useful way of approaching the debate over the passage of time is to consider the following thesis: The space-time thesis (SPT): Time is similar to the dimensions of space in at least this one respect: there is no set of properties such that (i) these properties are possessed by time, (ii) these properties are not possessed by any dimension (...) of space, and (iii) in virtue of time's possession of these properties it is true to say that time passes. Those who say that time does not pass generally want to affirm something like SPT. But those, on the other hand, who say that time does pass generally want to deny SPT. Of course, SPT is, as it stands, a mere skeleton of a thesis. It needs to be fleshed out. What could the relevant properties be? Why exactly would it be that in virtue of time's possession of these properties it is true to say that time passes? What exactly would it mean to say that time passes? These are all matters that require considerable discussion. The aim of this paper, however, is to take up some linguistic issues that have been considered central to the debate over the passage of time. There are two main reasons why I think it is appropriate to discuss these linguistic issues independently of the relevant metaphysical issues. The first reason is historical: many of the writers who have taken up the issue of whether or not time passes have begun their discussions by focusing on linguistic.. (shrink)

Este artículo se centra en un argumento presentado por Fara (2010) en contra del supervaluacionismo en el contexto de la vaguedad. Muestro cómo dicho argumento es igualmente aplicable al supervaluacionismo de tiempo ramificado (presentado por primera vez por Thomason 1970), pero no a la semántica 'STRL' de Malpass y Wawer (2012), que está estrechamente relacionada.

The thin red line ( TRL ) is a theory about the semantics of future-contingents. The central idea is that there is such a thing as the ‘actual future’, even in the presence of indeterminism. It is inspired by a famous solution to the problem of divine foreknowledge associated with William of Ockham, in which the freedom of agents is argued to be compatible with God’s omniscience. In the modern branching time setting, the theory of the TRL is widely regarded (...) to suffer from several fundamental problems. In this paper we propose several new TRL semantics, each with differing degrees of success. This leads up to our final semantics, which is a cross between the TRL and supervaluationism. We discuss the notions of truth, validity and semantic consequence which result from our final semantics, and demonstrate some of its pleasing results. This account, we believe, answers the main objection in the literature, and thus places the TRL on the same level as any other competing semantics for future contingents. (shrink)

The semantical structures called T x W frames were introduced in (Thomason, 1984) for the Ockhamist temporal-modal language, $[Unrepresented Character]_{o}$ , which consists of the usual propositional language augmented with the Priorean operators P and F and with a possibility operator ◇. However, these structures are also suitable for interpreting an extended language, $[Unrepresented Character]_{so}$ , containing a further possibility operator $\lozenge^{s}$ which expresses synchronism among possibly incompatible histories and which can thus be thought of as a cross-history 'simultaneity' operator. (...) In the present paper we provide an infinite set of axioms in $[Unrepresented Character]_{so}$ , which is shown to be strongly complete for T x W-validity. Von Kutschera (1997) contains a finite axiomatization of T x W-validity which however makes use of the Gabbay Irreflexivity Rule (Gabbay, 1981). In order to avoid using this rule, the proof presented here develops a new technique to deal with reflexive maximal consistent sets in Henkin-style constructions. (shrink)

I present a variant of with time, called, interpreted in standard Kripke semantics. On the syntactic level, is nothing but the extension of atemporal individual by: the future tense and past tense operators, and the operator of group agency for the grand coalition. A sound and complete axiomatisation for is given. Moreover, it is shown that supports reasoning about interesting normative concepts such as the concepts of achievement obligation and commitment.

In this paper we propose a method for modeling social influence within the STIT approach to action. Our proposal consists in extending the STIT language with special operators that allow us to represent the consequences of an agent’s choices over the rational choices of another agent.

Presentism says that only present objects exist. But the view has trouble grounding past-tensed truths like “dinosaurs existed”. Standard Eternalism grounds those truths by positing the existence of past objects—like dinosaurs. But Standard Eternalism conflicts with the intuition that there is genuine change—the intuition that there once were dinosaurs and no longer are any. I offer a novel theory of time—‘The Imprint’—that does a better job preserving both the grounding and genuine change intuitions. The Imprint says that the past and (...) present exist, but where the present exhibits mass-energy, the past only consists of curved empty regions of spacetime. We therefore avoid saying that there are dinosaurs, since there is no mass-energy in the past; but the curvature of the past gives us a way to ground the truth that “dinosaurs existed”. (shrink)

We prove that all finitely axiomatizable tense logics with temporal operators for ‘always in the future’ and ‘always in the past’ and determined by linear fows time are coNP-complete. It follows, for example, that all tense logics containing a density axiom of the form ■n+1F p → nF p, for some n ≥ 0, are coNP-complete. Additionally, we prove coNP-completeness of all ∩-irreducible tense logics. As these classes of tense logics contain many Kripke incomplete bimodal logics, we obtain many natural (...) examples of Kripke incomplete normal bimodal logics which are nevertheless coNP-complete. (shrink)

This paper presents structural similarities and historical connections between Prior’s rejection of the Barcan formula and his critique of Berkeley’s master argument for idealism in his 1955 paper “Berkeley in Logical Form”. Making use of Mackie’s paper “Self-Refutation—A Formal Analysis”, it concludes with some suggestions concerning what is at stake in the debate between Prior and Berkeley and in structurally similar debates such as whether to accept the Barcan formula.

Presentism is held by most to be the intuitive theory of time, due in large part to the view's supposed preservation of time's passage. In this paper, I strike a blow against presentism's intuitive pull by showing how the presentist, contrary to overwhelming popular belief, is unable to establish temporal change upon which the passage of time is based. I begin by arguing that the presentist's two central ontological commitments, the Present Thesis and the Change Thesis, are incompatible. The main (...) problem is that satisfying the Change Thesis to establish passage requires the existence of more than one moment. This conflicts with the Present Thesis that only the present moment exists. The presentist's response is to appeal to surrogates to stand proxy for the past, so as to account for the difference between what does exist and what did exist. I argue that, for this surrogate strategy to be successful, the proposed surrogates must track what actually happened. I demonstrate that there is no guarantee that t.. (shrink)

This paper explores how the meaning of evidentiality is temporally constrained, by investigating the meaning of Korean evidential sentences with –te. Unlike evidential sentences in languages that have previously been formally analyzed , e.g. Cuzco Quechua and Cheyenne, Korean evidential sentences with –te are compatible with both direct and indirect evidence types. In this paper, I analyze –te as an evidential that lexically encodes the meaning of a ‘sensory observation’. I account for the availability of both direct and indirect evidential (...) readings in terms of the variable temporal relation between relevant eventualities. I show that this temporal relation is compositionally determined by the interaction between –te and tense, and that it in turn constrains possible (direct vs. indirect) evidence types. I also provide empirical evidence for the modal meaning contributions of –te sentences, and develop a formal analysis in terms of Kratzer’s modal theory. The paper concludes by discussing the empirical and theoretical improvements of the proposed analysis over earlier analyses by Chung, and the implications for crosslinguistic studies of evidentials. (shrink)

We investigated, experimentally, the contention that the folk view, or naïve theory, of time, amongst the population we investigated is dynamical. We found that amongst that population, ~ 70% have an extant theory of time that is more similar to a dynamical than a non-dynamical theory, and ~ 70% of those who deploy a naïve theory of time deploy a naïve theory that is more similar to a dynamical than a non-dynamical theory. Interestingly, while we found stable results across our (...) two experiments regarding the percentage of participants that have a dynamical or non-dynamical extant theory of time, we did not find such stability regarding which particular dynamical or non-dynamical theory of time they take to be most similar to our world. This suggests that there might be two extant theories in the population—a broadly dynamical one and a broadly non-dynamical one—but that those theories are sufficiently incomplete that participants do not stably choose the same dynamical theory as being most similar to our world. This suggests that while appeals to the ordinary view of time may do some work in the context of adjudicating disputes between dynamists and non-dynamists, they likely cannot do any such work adjudicating disputes between particular brands of dynamism. (shrink)

The situation calculus is one of the most established formalisms for reasoning about action and change. In this paper we will review the basics of Reiter’s version of the situation calculus, show how knowledge and time have been addressed in this framework, and point to some of the weaknesses of the situation calculus with respect to time. We then present a modal version of the situation calculus where these problems can be overcome with relative ease and without sacrificing the advantages (...) of the original. (shrink)

Let $\mathcal{L}$ be a propositional language with standard Boolean connectives plus two modalities: an S4-ish topological modality $\square$ and a temporal modality $\bigcirc$ , understood as ‘next’. We extend the topological semantic for S4 to a semantics for the language $\mathcal{L}$ by interpreting $\mathcal{L}$ in dynamic topological systems, i.e. ordered pairs $\langle X, f\rangle$ , where X is a topological space and f is a continuous function on X. Artemov, Davoren and Nerode have axiomatized a logic S4C, and have shown (...) that S4C is sound and complete for this semantics. Zhang and Mints have shown that S4C is complete relative to a particular topological space, Cantor space. The current paper produces an alternate proof of the Zhang-Mints result. (shrink)

In this paper I propose a novel treatment of generic sentences, which proceeds by means of different levels of analysis. According to this account, all generic sentences (I-generics and D-generics alike) are initially treated in a uniform manner, as involving higher-order predication (following the work of George Boolos, James Higginbotham and Barry Schein on plurals). Their non-uniform character, however, re-emerges at subsequent levels of analysis, when the higher-order predications of the first level are cashed out in terms of quantification over (...) individuals: this last step, I suggest, involves knowledge concerning the lexical meaning of the predicates in question. (shrink)

Open future is incompatible with realism about possible worlds. Since realistically conceived (concrete or abstract) possible worlds are maximal in the sense that they contain/represent the full history of a possible spacetime, past and future included, if such a world is actual now, the future is fully settled now, which rules out openness. The kind of metaphysical indeterminacy required for open future is incompatible with the kind of maximality which is built into the concept of possible worlds. The paper discusses (...) various modal realist responses and argues that they provide ersatz openness only, or they lead to incoherence, or they render the resulting theory inadequate as a theory of modality. The paper also considers various accounts of the open future, including rejection of bivalence, supervaluationism, and the ‘thin red line’ view (TRL), and claims that a version of (TRL) can avoid the incompatibility problem, but only at the cost of deflating the notion of openness. (shrink)

This paper is predicated on the idea that some modal operators are better understood as quantificational expressions over worlds that determine not only first-order facts but modal facts also. In what follows, we will present a framework in which these two types of facts are brought closer together. Structural features will be located in the worlds themselves. This result will be achieved by decomposing worlds into parts, where some of these parts will have “modal import” in the sense that they (...) will determine structure on other worldly parts. The main upshot of this will be a clearer grasp of the interaction between modal notions. (shrink)

The connection between the probabilities of conditionals and the corresponding conditional probabilities has long been explored in the philosophical literature, but its implementation faces both technical obstacles and objections on empirical grounds. In this paper I ?rst outline the motivation for the probabilistic turn and Lewis’ triviality results, which stand in the way of what would seem to be its most straightforward implementation. I then focus on Richard Jeffrey’s ’random-variable’ approach, which circumvents these problems by giving up the notion that (...) conditionals denote propositions in the usual sense. Even so, however, the random-variable approach makes counterintuitive predictions in simple cases of embedded conditionals. I propose to address this problem by enriching the model with an explicit representation of causal dependencies. The addition of such causal information not only remedies the shortcomings of Jeffrey’s conditional, but also opens up the possibility of a uni?ed probabilistic account of indicative and counterfactual conditionals. (shrink)

Two new infinitary modal logics are simply obtained from a Gentzen-type sequent calculus for infinitary logic by adding a next-time operator, and a program operator, respectively. It is shown that an any-time operator and a program-iteration operator can respectively be expressed using infinitary conjunction in these logics. The cut-elimination and completeness theorems for these logics are proved using some theorems for embedding these logics into (classical) infinitary logic.

RESUMO: A presente investigação questiona a essência teo-lógica dos futuros contingentes. Para o efeito, analisa-se, primeiramente, a argumentação segundo a qual, sob certas condições lógicas, teológicas, ontológicas e cosmológicas antinecessitantes, detetadas por G. W. Leibniz, a abertura contingente do futuro parece ser compatível com o regime das "verdades contingentes pré-determinadas", regime enquadrado teologicamente pelo princípio do "futuro melhor" ou do "único futuro verdadeiro". No entanto, os futuros contingentes incitam, com e contra Aristóteles, ao desenvolvimento de uma lógica temporal e plurivalente, (...) ao modo de J. Łukasiewicz ou A. Prior. Essa lógica garante a abertura do futuro sem o oneroso custo metafísico da adesão a uma teo-lógica omnideterminante. A crítica do determinismo lógico, daí resultante, afigura-se mais coadunável com as condições pós-metafísicas inerentes à episteme agnósticacontemporânea, mas, nesse caso, a abertura do futuro implicaria uma profunda redefinição das próprias ideias e funções de "Deus", "matéria", "história" e "verdade". ABSTRACT: This paper investigates the theological essence of contingent futures. First, it analyses the argument according to which, under certain logical, theological, ontological, and cosmological conditions detected by Leibniz, the contingent openness of the future may be compatible with the regime of "pre- determined contingent truths", theologically grounded in the principle of an "optimal future" or a "single true future". However, the examination of contingent futures has also fostered, both for and against Aristotle's position, the development of a many-valued and temporal logic as proposed by J. Łukasiewicz or A. Prior. This logic safeguards the openness of future without the metaphysically expensive cost of adhering to an all-determining theo-logic. It hence follows that the critique of logical determinism seems to be more appropriate to express the post-metaphysical conditions of our present agnostic mentality. In this case, however, the openness of the future would entail a profound redefinition of the very ideas and functions of "God", "matter", "history", and "truth". (shrink)

Investigation into the reality of time can be pursued within the ontological domain or it can also span human thought and natural language. I propose to approach time by correlating three domains of inquiry: metaphysical time, the human concept of time, and temporal reference in natural language, entertaining the possibility of what I call a ‘horizontal reduction’ and ‘vertical reduction’. I present a view of temporalityL/E as epistemic modality, drawing on evidence from the L domain and its correlates in the (...) E and M domains. On this view, the human concept of time is a complex, ‘molecular’ concept and can be broken down into primitive concepts that are modal in nature, featuring as degrees of epistemic commitment to representations of states of affairs. I present evidence from tensed and tenseless languages and point out its compatibility with the view of real time as metaphysical modality. (shrink)

We propose a non-standard interpretation of Alternating-time Temporal Logic with imperfect information, for which no commonly accepted semantics has been proposed yet. Rather than changing the semantic structures, we generalize the usual interpretation of formulae in single states to sets of states. We also propose a new epistemic operator for ?practical? or ?constructive? knowledge, and we show that the new logic (which we call Constructive Strategic Logic) is strictly more expressive than most existing solutions, while it retains the same model (...) checking complexity. Finally, we study properties of constructive knowledge and other operators in this non-standard semantics. (shrink)

In 1954, A. N. Prior discovered a way to formalize tense-logic—as such, there is no doubt that he is the father of modern tense-logic. Despite this, he considered his early teacher in p...

Recently scholars have discovered a diary entry of Arthur Norman Prior dated the 25 March 1942, in which Prior is reflecting on his own views and attitudes towards theology. The purpose of the present article is to consider what the diary entry can teach us about this period of transition in Prior’s life, and its effects upon his philosophical interests. This article will argue that the diary entry provides an explanation for why theology continued to be significant in Prior’s work.

On the historic Cross, it is God Himself Who has actually met the last dark limits of our life, and has brought Himself face to face with that inescapable something (or Someone) which seems to keep us forever strangers (physically, morally, logically and in every other way) to the Absolute and Eternal. And because it is God Himself Who has thus in life and in death personally encountered sin, death, time and corruption, He has overthrown them and raised and transformed (...) the existence that is subject to them, our existence, into the glorious Being of His Everlasting Godhead. He has robbed death of its sting and the grave of its victory, and delivered us from Satan's ancient power. A.N. Prior: Athanasius Contra Mundum. Prior (1934). (shrink)

Logical realism, by Arthur Norman Prior understood as the view that logic is not about language but about reality, is a consistent and strong tenet in all of Prior's philosophical work. Recent disc...