• Impossible Worlds
    Oxford University Press. 2019.
    Impossible Worlds focuses on an exciting new theory in philosophy, with applications in metaphysics, logic, and the theory of meaning. Its central topic is: how do we meaningfully talk and reason about situations which, unbeknownst to us, are impossible? This issue emerges as a central problem in contemporary philosophical accounts of meaning, information, knowledge, belief, fiction, conditionality, and counterfactual supposition. The book is written bytwo of the leading philosophers in the area…Read more
  •  123
    Theodore Sider: The Tools of Metaphysics and the Metaphysics of Science (review)
    Journal of Philosophy 118 (1): 51-55. 2021.
  •  267
    Which Fitch?
    Analysis. forthcoming.
    Jago uses a Fitch-style argument in an attempt to demonstrate that every truth has a truthmaker (maximalism). But Trueman shows there’s a parallel argument, this time to the conclusion that no truth has a truthmaker. Since we can’t accept both, we must ditch at least one Fitch. But which?
  •  214
    Disjunctive Parts
    In Federico L. G. Faroldi & Frederik Van De Putte (eds.), Outstanding Contributions to Logic: Kit Fine, Springer. forthcoming.
    Fine (2017a) sets out a theory of content based on truthmaker semantics which distinguishes two kinds of consequence between contents. There is entailment, corresponding to the relationship between disjunct and disjunction, and there is containment, corresponding to the relationship between conjunctions and their conjuncts. Fine associates these with two notions of parthood: disjunctive and conjunctive. Conjunctive parthood is a very useful notion, allowing us to analyse partial content and part…Read more
  •  150
    Private Schools and Queue‐jumping: A reply to White
    Journal of Philosophy of Education 54 (5): 1201-1205. 2020.
    John White (2016) defends the UK private school system from the accusation that it allows an unfair form of ‘queue jumping’ in university admissions. He offers two responses to this accusation, one based on considerations of harm, and one based on meritocratic distribution of university places. We will argue that neither response succeeds: the queue-jumping argument remains a powerful case against the private school system in the UK. We begin by briefly outlining the queue-jumping argument (§1),…Read more
  •  8
    The Problem of Rational Knowledge
    Erkenntnis 79 (Suppl 6): 1151-1168. 2014.
    Real-world agents do not know all consequences of what they know. But we are reluctant to say that a rational agent can fail to know some trivial consequence of what she knows. Since every consequence of what she knows can be reached via chains of trivial cot be dismissed easily, as some have attempted to do. Rather, a solution must give adequate weight to the normative requirements on rational agents’ epistemic states, without treating those agents as mathematically ideal reasoners. I’ll argue …Read more
  •  73
    Logic for exact entailment
    with Kit Fine
    Review of Symbolic Logic 12 (3): 536-556. 2019.
    An exact truthmaker for A is a state which, as well as guaranteeing A’s truth, is wholly relevant to it. States with parts irrelevant to whether A is true do not count as exact truthmakers for A. Giving semantics in this way produces a very unusual consequence relation, on which conjunctions do not entail their conjuncts. This feature makes the resulting logic highly unusual. In this paper, we set out formal semantics for exact truthmaking and characterise the resulting notion of entailment, sho…Read more
  •  24
    The Metaphysics of Truth, by Douglas Edwards
    Mind 128 (511): 970-976. 2019.
    The Metaphysics of Truth, by EdwardsDouglas. Oxford: Oxford University Press, 2018. Pp. 208.
  •  96
    Impossible Worlds
    Oxford University Press. 2013.
    We need to understand the impossible. Francesco Berto and Mark Jago start by considering what the concepts of meaning, information, knowledge, belief, fiction, conditionality, and counterfactual supposition have in common. They are all concepts which divide the world up more finely than logic does. Logically equivalent sentences may carry different meanings and information and may differ in how they're believed. Fictions can be inconsistent yet meaningful. We can suppose impossible things withou…Read more
  •  497
    Truthmaker Semantics for Relevant Logic
    Journal of Philosophical Logic 49 (4): 681-702. 2020.
    I develop and defend a truthmaker semantics for the relevant logic R. The approach begins with a simple philosophical idea and develops it in various directions, so as to build a technically adequate relevant semantics. The central philosophical idea is that truths are true in virtue of specific states. Developing the idea formally results in a semantics on which truthmakers are relevant to what they make true. A very natural notion of conditionality is added, giving us relevant implication. I t…Read more
  •  628
    A short argument for truthmaker maximalism
    Analysis 80 (1): 40-44. 2020.
    Each truth has a truthmaker: an entity in virtue of whose existence that truth is true. So say truthmaker maximalists. Arguments for maximalism are hard to find, whereas those against are legion. Most accept that maximalism comes at a significant cost, which many judge to be too high. The scales would seem to be balanced against maximalism. Yet, as I show here, maximalism can be derived from an acceptable premise which many will pre-theoretically accept.
  •  76
    Properties, by Douglas Edwards: Cambridge: Polity Press, 2014, pp. xiii + 181, £15.99
    Australasian Journal of Philosophy 93 (3): 626-626. 2015.
    Review of Properties, by Douglas Edwards (Cambridge: Polity Press, 2014)
  •  320
    Logic for Exact Entailment
    with Kit Fine
    Review of Symbolic Logic 1-21. 2018.
    An exact truthmaker for A is a state which, as well as guaranteeing A’s truth, is wholly relevant to it. States with parts irrelevant to whether A is true do not count as exact truthmakers for A. Giving semantics in this way produces a very unusual consequence relation, on which conjunctions do not entail their conjuncts. This feature makes the resulting logic highly unusual. In this paper, we set out formal semantics for exact truthmaking and characterise the resulting notion of entailment, sho…Read more
  •  274
    Knowing how things might have been
    Synthese (Suppl 8): 1-19. 2018.
    I know that I could have been where you are right now and that you could have been where I am right now, but that neither of us could have been turnips or natural numbers. This knowledge of metaphysical modality stands in need of explanation. I will offer an account based on our knowledge of the natures, or essencess, of things. I will argue that essences need not be viewed as metaphysically bizarre entities; that we can conceptualise and refer to essences; and that we can gain knowledge of them…Read more
  •  172
    Essential bundle theory and modality
    Synthese (Suppl 6): 1-16. 2018.
    Bundle theories identify material objects with bundles of properties. On the traditional approach, these are the properties possessed by that material object. That view faces a deep problem: it seems to say that all of an object’s properties are essential to it. Essential bundle theory attempts to overcome this objection, by taking the bundle as a specification of the object’s essential properties only. In this paper, I show that essential bundle theory faces a variant of the objection. To avoid…Read more
  •  266
    Material Objects and Essential Bundle Theory
    Philosophical Studies 175 (12): 2969-2986. 2018.
    In this paper we present a new metaphysical theory of material objects. On our theory, objects are bundles of property instances, where those properties give the nature or essence of that object. We call the theory essential bundle theory. Property possession is not analysed as bundle-membership, as in traditional bundle theories, since accidental properties are not included in the object’s bundle. We have a different story to tell about accidental property possession. This move reaps many benef…Read more
  •  155
    Modal realism, still at your convenience
    Analysis 77 (2): 299-303. 2017.
    Divers presents a set of de re modal truths which, he claims, are inconvenient for Lewisean modal realism. We argue that there is no inconvenience for Lewis.
  •  103
    What Truth Is
    Oxford University Press. 2018.
    Mark Jago presents and defends a novel theory of what truth is, in terms of the metaphysical notion of truthmaking. This is the relation which holds between a truth and some entity in the world, in virtue of which that truth is true. By coming to an understanding of this relation, he argues, we gain better insight into the metaphysics of truth. The first part of the book discusses the property being true, and how we should understand it in terms of truthmaking. The second part focuses on truthma…Read more
  •  995
    The Truthmaker Non-Maximalist's Dilemma
    Mind 121 (484): 903-918. 2012.
    Amongst those who feel the pull of the truthmaker principle (that truths require for their truth a truthmaker to exist), there is disagreement as to whether it applies to all truths or merely to some distinguished subset. Those in the latter camp, the non-maximalists, argue that there are no ducks in my bath is true not because of something’s existence, but because of the lack of ducks in my bath. Maximalists, by contrast, insist that truths are made true by something’s existence, and so appear …Read more
  • Reality Making (edited book)
    Oxford University Press UK. 2016.
    What makes up reality, and how? What kinds of entity are fundamental to reality, and how do dependent entities depend on the fundamental ones? How does one entity metaphysically ground another? These questions are central to contemporary metaphysics. The papers in this collection, written by a new generation of metaphysicians, address these and related questions. They investigate the metaphysical concepts of grounding and fundamentality, and the relationship between the fundamental and all the o…Read more
  •  1049
    Impossible Worlds
    Noûs 47 (3): 713-728. 2013.
    Impossible worlds are representations of impossible things and impossible happenings. They earn their keep in a semantic or metaphysical theory if they do the right theoretical work for us. As it happens, a worlds-based account provides the best philosophical story about semantic content, knowledge and belief states, cognitive significance and cognitive information, and informative deductive reasoning. A worlds-based story may also provide the best semantics for counterfactuals. But to function …Read more
  •  289
    Logical information and epistemic space
    Synthese 167 (2). 2009.
    Gaining information can be modelled as a narrowing of epistemic space . Intuitively, becoming informed that such-and-such is the case rules out certain scenarios or would-be possibilities. Chalmers’s account of epistemic space treats it as a space of a priori possibility and so has trouble in dealing with the information which we intuitively feel can be gained from logical inference. I propose a more inclusive notion of epistemic space, based on Priest’s notion of open worlds yet which contains …Read more
  •  138
    Epistemic logic for rule-based agents
    Journal of Logic, Language and Information 18 (1): 131-158. 2009.
    The logical omniscience problem, whereby standard models of epistemic logic treat an agent as believing all consequences of its beliefs and knowing whatever follows from what else it knows, has received plenty of attention in the literature. But many attempted solutions focus on a fairly narrow specification of the problem: avoiding the closure of belief or knowledge, rather than showing how the proposed logic is of philosophical interest or of use in computer science or artificial intelligence.…Read more
  •  157
    Indexicals, fictions, and ficta
    Dialectica 57 (2). 2003.
    We defend the view that an indexical uttered by an actor works on the model of deferred reference. If it defers to a character which does not exist, it is an empty term, just as ‘Hamlet’ and ‘Ophelia’ are. The utterance in which it appears does not express a proposition and thus lacks a truth value. We advocate an ontologically parsimonious, anti-realist, position. We show how the notion of truth in our use and understanding of indexicals (and fictional names) as they appear within a fiction is …Read more
  •  517
    The cost of truthmaker maximalism
    Canadian Journal of Philosophy 43 (4): 460-474. 2013.
    According to truthmaker theory, particular truths are true in virtue of the existence of particular entities. Truthmaker maximalism holds that this is so for all truths. Negative existential and other ‘negative’ truths threaten the position. Despite this, maximalism is an appealing thesis for truthmaker theorists. This motivates interest in parsimonious maximalist theories, which do not posit extra entities for truthmaker duty. Such theories have been offered by David Lewis and Gideon Rosen, Ros…Read more
  •  1841
    Recent Work in Relevant Logic
    Analysis 73 (3): 526-541. 2013.
    This paper surveys important work done in relevant logic in the past 10 years.
  •  791
    Advanced Modalizing Problems
    Mind 125 (499): 627-642. 2016.
    I present an internal problem for David Lewis’s genuine modal realism. My aim is to show that his analysis of modality is inconsistent with his metaphysics. I consider several ways of modifying the Lewisian analysis of modality, but argue that none are successful. I argue that the problem also affects theories related to genuine modal realism, including the stage theory of persistence and modal fictionalism.
  •  414
    Syntactic logics do not suffer from the problems of logical omniscience but are often thought to lack interesting properties relating to epistemic notions. By focusing on the case of rule-based agents, I develop a framework for modelling resource-bounded agents and show that the resulting models have a number of interesting properties.