Gonzalo Rodriguez-Pereyra (2006) argues against attempts to preserve the entailment principle (or a restriction of it) while avoiding the explosion of truthmakers for necessities and truthmaker triviality. In doing so, he both defends the disjunction thesis--if something makes true a disjunctive truth, then it makes true one of its disjuncts--, and rejects the conjunction thesis--if something makes tue a conjunctive truth, then it makes true each of its conjuncts. In my discussion, I provide plausible counterexamples to the disjunction (...) thesis, and contend that Rodriguez-Pereyra's general defence of it fails. Then I defend the conjunction thesis from Rodriguez-Pereyra's case against it. (shrink)

Ali Enayat had asked whether two halves of Disjunctive Correctness ([Formula: see text]) for the compositional truth predicate are conservative over Peano Arithmetic (PA). In this paper, we show that the principle “every true disjunction has a true disjunct” is equivalent to bounded induction for the compositional truth predicate and thus it is not conservative. On the other hand, the converse implication “any disjunction with a true disjunct is true” can be conservatively added to [Formula: see text]. The (...) methods introduced here allow us to give a direct nonconservativeness proof for [Formula: see text]. (shrink)

This paper defends the case against (sparse) disjunctive properties by means of four Armstrongian arguments. The first of these is a logical atomist argument from truthmaking, which is, broadly speaking, ‘Armstrongian’ (Armstrong 1997). This argument is strong – although it stands or falls with the relevant notion of truthmaking, as it were. However, three arguments, which are prima facie independent of truthmaking, can be found explicitly early in Armstrong’s middle period. Two of these early arguments face a serious objection put (...) forward forcefully by Louise Antony (2003) and Alan Penczek (1997), respectively. I consider these objections and argue that they fail. Thus, even if the argument from truthmaking is indecisive, disjunctive properties should be rejected. (shrink)

The disjunction problem and the distality problem each presents a challenge that any theory of mental content must address. Here we consider their bearing on purely probabilistic causal theories. In addition to considering these problems separately, we consider a third challenge—that a theory must solve both. We call this “the hard problem.” We consider 8 basic ppc theories along with 240 hybrids of them, and show that some can handle the disjunction problem and some can handle the distality (...) problem, but none can handle the hard problem. This is our main result. We then discuss three possible responses to that result, and argue that though the first two fail, the third has some promise. (shrink)

We systematically study several versions of the disjunction and the existence properties in modal arithmetic. First, we newly introduce three classes $\mathrm {B}$, $\Delta (\mathrm {B})$, and $\Sigma (\mathrm {B})$ of formulas of modal arithmetic and study basic properties of them. Then, we prove several implications between the properties. In particular, among other things, we prove that for any consistent recursively enumerable extension T of $\mathbf {PA}(\mathbf {K})$ with $T \nvdash \Box \bot $, the $\Sigma (\mathrm {B})$ -disjunction (...) property, the $\Sigma (\mathrm {B})$ -existence property, and the $\mathrm {B}$ -existence property are pairwise equivalent. Moreover, we introduce the notion of the $\Sigma (\mathrm {B})$ -soundness of theories and prove that for any consistent recursively enumerable extension of $\mathbf {PA}(\mathbf {K4})$, the modal disjunction property is equivalent to the $\Sigma (\mathrm {B})$ -soundness. (shrink)

Reverse mathematics is a program in the foundations of mathematics founded by Friedman and developed extensively by Simpson and others. The aim of RM is to find the minimal axioms needed to prove a theorem of ordinary, that is, non-set-theoretic, mathematics. As suggested by the title, this paper deals with two RM-phenomena, namely, splittings and disjunctions. As to splittings, there are some examples in RM of theorems A, B, C such that A↔, that is, A can be split into two (...) independent parts B and C. As to disjunctions, there are examples in RM of theorems D, E, F such that D↔, that is, D can be written as the disjunction of two independent parts E and F. By contrast, we show in this paper that there is a plethora of splittings and disjunctions in Kohlenbach’s higher-order RM. (shrink)

The paper explores the disjunctive riddle for induction: If we know the sample Ks to be P, we also know that they are P or F. Assuming that we also know that the future Ks are non-P, we can conclude that they are F, if only we can inductively infer the evidentially supported P-or-F hypothesis. Yet this is absurd. We cannot predict that future Ks are F based on the knowledge that the samples, and only they, are P. The ensuing (...) challenge is to account for the unprojectibility of the disjunctive hypothesis. I provide an explanation in terms of epistemic dependence. The P-or-F hypothesis is unprojectible because the evidence supporting it depends epistemically on the evidence for the defeated P-hypothesis. The paper also shows that the disjunctive riddle covers the essence of Goodman's infamous grue-problem, which, therefore, can be resolved by the same means: In contrast to the green-hypothesis, the grue-hypothesis is unprojectible because the grue-evidence depends on the evidence for a defeated hypothesis. (shrink)

I explore constructions which contain an embedded disjunction ⌜p or q⌝which is interpreted as (p∨q) ∧♢p∧♢q, where ♢is a possibility modal whose flavor is epistemic, circumstantial, or deontic. I argue that no extant theory can account for these interpretations. I propose that the best way to do so is with a direct theory on which ⌜p or q⌝ simply means (p∨q) ∧♢p∧♢q. In addition to accounting for the novel cases I discuss, this theory explains both wide- and narrow-scope free (...) choice inferences, in a similar way as the theories of Zimmermann (2000); Geurts (2005); Goldstein (2019). It also accounts for recent observations about the relation between disjunction and possibility from Degano et al. 2025; Feinmann 2023. (shrink)

Disjunctive antecedent conditionals —conditionals of the form if A or B, C—sometimes seem to entail both of their simplifications and sometimes seem not to. I argue that this behavior reveals a genuine ambiguity in DACs. Along the way, I discuss a new observation about the role of focal stress in distinguishing the two interpretations of DACs. I propose a new theory, according to which the surface form of a DAC underdetermines its logical form: on one possible logical form, if A (...) or B, C does entail both of its simplifications, while on the other, it does not. (shrink)

Sentences with disjunction in the scope of a universal quantifier, Every A is P or Q, tend to give rise to distributive inferences that each of the disjuncts holds of at least one individual in the domain of the quantifier, Some A is P & Some A is Q. These inferences are standardly derived as an entailment of the meaning of the sentence together with the scalar implicature that it is not the case that either disjunct holds of every (...) individual in the domain of the quantifier, \Every A is P &\Every A is Q. As we show, this derivation faces a challenge in that distributive inferences may obtain in the absence of plain negated inferences. We address this challenge by showing that on particular assumptions about alternatives, a derivation of distributive inferences as scalar implicatures can be maintained without in fact necessitating plain negated inferences. These assumptions accord naturally with the grammatical approach to scalar implicatures. We also present experimental data that suggest that plain negated inferences are not only unnecessary for deriving distributive inferences, but might in fact be unavailable. (shrink)

In this paper I deal with the relation between the disjunction thesis—that the truthmaking relation is distributed over a disjunction—and the necessary connection thesis—that the existence of some entities requires the existence of other distinct entities. I will first show that because of this very relation, the arguments for and against the disjunction thesis that overlook its metaphysical considerations will fail. Finally, I will show that the commitment produced by truthmaker maximalism to totality states of affairs, or (...) some relevantly similar things, requires one to accept a necessary connection that disaffirms the disjunction thesis. (shrink)

This paper is a contribution to the general study of consequence relations which contain (definable) connective of “disjunction”. Our work is centered around the “proof by cases property”, we present several of its equivalent definitions, and show some interesting applications, namely in constructing axiomatic systems for intersections of logics and recognizing weakly implicative fuzzy logics among the weakly implicative ones.

John McDowell's conception of perceptual knowledge commits him to the claim that if I perceive that P then I am in a position to know that I perceive that P. In the first part of this essay, I present some reasons to be suspicious of this claim - reasons which derive from a general argument against 'luminosity' - and suggest that McDowell can reject this claim, while holding on to almost all of the rest of his conception of perceptual knowledge, (...) by supplementing his existing disjunctive conception of experience with a new disjunctive conception of perceiving. In the second part of the essay, I present some reasons for thinking that one's justification, in cases of perceptual knowledge, consists not in the fact that one perceives that P but in the fact that one perceives such-and-such. I end by suggesting that the disjunctive conception of perceiving should be understood as a disjunctive conception of perceiving such-and-such. (shrink)

A reformulation of the Kochen and Specker Theorem is used to show how quantum disjunctive facts have presented an insurmountable obstacle to mainstream attempts to motivate quantum logic. The failure of these attempts represents a progressive retrenchment of the program of connecting quantum logic to quantum theory. However, a recent program proposed by Allen Stairs gives those who embrace a realist ontology of quantum "facts" reason to believe quantum logic may yet be read off quantum theory.

This paper is a response to replies by Dan López de Sa and Mark Jago to my ‘Truthmaking, Entailment, and the Conjuction Thesis’. In that paper, my main aim was to argue against the Entailment Principle by arguing against the Conjunction Thesis, which is entailed by the Entailment Principle. In the course of so doing, although not essential for my project in that paper, I defended the Disjunction Thesis. López de Sa has objected both to my defence of the (...) Disjunction Thesis and my case against the Conjunction Thesis. I shall show that his objections are unfounded and based on serious misunderstandings of my position, what the relevant debate is, and some fundamental notions of Truthmaker Theory. Jago argues that accepting the Disjunction Thesis and rejecting the Conjunction Thesis is hard to maintain. But I show that Jago has not shown that accepting the Disjunction Thesis while rejecting the Conjunction Thesis is impossible or even hard to maintain. Jago believes that, to accept the Disjunction Thesis while rejecting the Conjunction Thesis, one needs to reject his axiom (T3), which says that all the truthmakers for <P&P> are truthmakers for <P>. I argue that there are reasons to reject such a principle, and the version of it that says that what makes <P&P> true makes <P> true. (shrink)

Direct Informational Semantics, according to which [X]s represent X if ‘Xs cause [X]s’ is a law, and Fodorian naturalistic semantics both suffer from double disjunctivitis. I argue that robustness, properly construed, characterizes both represented properties and representing symbols: two or more properties normally regarded as non-disjunctive may each be nomologically connected to a non-disjunctive symbol, and two or more non-disjunctive symbols may each be nomologically connected to a property. This kind of robustness bifurcates the so-called disjunction problem into a (...) Represented-Disjunction Problem, of which Fodor was aware, and a Representer-Disjunction Problem, of which he was on the whole oblivious. Fodor fails to solve these problems: his solution to the former, the Asymmetric Dependence Condition, presupposes a successful solution to the latter, while possible responses that Fodor might make to the latter either beg the former or cannot be met or else flout the Naturalistic Requirement and the Atomistic Requirement. Even setting the Representer-Disjunction Problem aside, the Represented-Disjunction Problem does not get solved, because the robustness involving phonological/orthographic sequences guarantees that nothing can meet the Asymmetrical Dependence Condition. Indeed there is a serious problem of individuating phonological/orthographic tokens and types in a manner that satisfies Fodor’s expectations. This is made manifest by the presence of orthographic tokens embedded in larger tokens. (shrink)

If Andrea knows that Biden won the last presidential election, then they also know that either Biden won the last presidential election, or Biden is a reptilian. This is the response that epistemic logics based on standard Kripke relational semantics provide, which is consistent with the fact that minimally rational agents can perform disjunction introduction. This is not the case in topic-sensitive semantics though. An agent might not grasp the concept of what a reptilian is, and therefore not be (...) able to know any proposition dealing with reptilians. By employing the concept of logical grounding, I propose a semantics that keeps the requirement of topic-grasping but weakens it, re-establishing a more standard treatment of disjunction, in line with the capacities of minimally rational agents. The paper is structured as follows. In Section 2 I introduce topic-sensitive semantics. In Section 3 I introduce the concept of logical grounding – focusing on the grounds of disjunction – and motivate some desiderata. The concept of minimal topic, the core of my proposal, is detailed in Section 4 and exploited in Section 5 to propose a new topic-sensitive semantic clause for knowledge. I conclude in Section 6. (shrink)

Two different kinds of multiple-conclusion consequence relations taken from Shoesmith and Smiley and Galatos and Tsinakis or Nowak, called here disjunctive and conjunctive, respectively, defined on a formal language, are considered. They are transferred into a bounded lattice and a complete lattice, respectively. The properties of such abstract consequence relations are presented.

There is an initial presumption against disjunctive causes. First of all, for some people causation is a relation between events. But, arguably, there are no disjunctive events, since events are particulars and thus they have spatiotemporal locations, while it is unclear what the spatiotemporal location of a disjunctive event could be.1 More importantly, even if one believes that entities like facts can enter in causal relations, and even if there are disjunctive facts, it is still hard to see how disjunctive (...) facts could be causes. Imagine, for instance, the following scenario. I have a gun filled with red paint and another gun filled with blue paint, and I fire both guns at my neighbor’s white wall. A moment later, there is a graffiti on the wall and my neighbor notifies the police. He would have done so regardless of the graffiti’s color, since all he cares about is the existence of a graffiti on his wall. Is it plausible to claim that a disjunctive fact is a cause of his notifying the police? In particular, is it plausible to claim that he notified the police because I fired the red-paint gun or the blue-paint gun (the thought being that my firing paint of either color would have sufficed)? It seems not. The police was notified because of the actual graffiti on the wall, and the actual graffiti on the wall is made of a certain pattern of colored patches. Imagine, that, as it turns out, there are patches of both colors on the wall. Then it seems that both my firing the red-paint gun and my firing the blue-paint gun were causes of my neighbor’s notifying the police. In other words, my firing the red-paint gun and my firing the blue-paint gun jointly caused the outcome: each of them was a contributory cause of the outcome’s occurrence. On the other hand, imagine that there are only patches of one color on the wall. Then it seems that my firing only one of the guns was a cause. Either way, the disjunction fails to be a cause: either my firing the red-paint gun was a cause, or my firing the blue-paint gun was a cause, or they were both causes, but their disjunction was not.. (shrink)

Globalization is now at its most disjunctive phase in human history. The planetary COVID-19 crisis has combined with the vulnerabilities of global capitalism to break down social routines. Yet, the current moment of the Great Unsettling also offers a critical opportunity to take stock of the present state of globalization. To this end, this article revisits and re-engages some pertinent themes raised in the pathbreaking 1990 TCS Global Culture issue. In particular, the article explores the crucial role of structural divergences (...) that have been developing among major formations of globalization. Gaining a better understanding of the current globalization system requires a new conceptual framework that captures different formations of globalization, ranging from the embodied to the disembodied. The multiple disjunctive relationships that have developed among and within these formations shape not only the morphology of the contemporary globalization system but also cast a long shadow on its future dynamics. (shrink)

I develop a ‘duty-plus’ approach to supererogation based on a simple intuition: if I am required to do x or y, doing x and y is a candidate for, though not necessarily, supererogation. This is an appealing view to take, located midway between two extreme positions, supererogationism and rigorism. I give a precise statement of the view through the notion of disjunctive duties, and discuss the commitments a duty-plus theorist should make, independent from the Kantian context in which this position (...) is often discussed. I also advocate the novel claim that we should take supererogation as a property of sets of actions, rather than single actions. The latter view suffers from problems in cases of concurrent acts and accumulative supererogation. (shrink)

This is a comprehensive study of the English word 'or', and the logical operators variously proposed to present its meaning. Although there are indisputably disjunctive uses of or in English, it is a mistake to suppose that logical disjunction represents its core meaning. 'Or' is descended from the Anglo-Saxon word meaning second, a form which survives in such expressions as "every other day." Its disjunctive uses arise through metalinguistic applications of an intermediate adverbial meaning which is conjunctive rather than (...) disjunctive in character. These conjunctive uses have puzzled philosophers and logicians, and have been discussed extensively under such headings as "free choice permission." This study examines the textbook myths that have clouded our understanding of how or and other "logical" vocabulary comes to have something approaching its logical meaning in natural languages. It considers the various historical conceptions of disjunction and its place in logic from the Stoics to the present day. (shrink)

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 partial truth. In this chapter, I extend the notion of disjunctive (...) parthood in terms of a structural relation of refinement, which stands to disjunctive parthood much as mereological parthood stands to conjunctive parthood. Philosophically, this relation may be modelled on the determinable- determinate relation, or on a fact-to-fact notion of grounding. I discuss its connection to two other Finean notions: vagueness (understood via precisification) and arbitrary objects. I then investigate what a logic of truthmaking with refinement might look like. I argue that (i) parthood naturally gives rise to a relevant conditional; (ii) refinement underlies a relevant notion of disjunction; and so (iii) truthmaker semantics with refinement is a natural home for relevant logic. The resulting formal models draw on Fine’s (1974) semantics for relevant logics. Finally, I use this understanding of relevant semantics to investigate the status of the mingle axiom. (shrink)

In contrast to Hintikka’s enormously complex distributive normal forms of first- order logic, this paper shows how to generate minimized disjunctive normal forms of first-order logic. An effective algorithm for this purpose is outlined, and the benefits of using minimized disjunctive normal forms to explain the truth conditions of propo- sitions expressible within pure first-order logic are presented.

We provide a new link between deductive and probabilistic reasoning fallacies. Illusory inferences from disjunction are a broad class of deductive fallacies traditionally explained by recourse to a matching procedure that looks for content overlap between premises. In two behavioral experiments, we show that this phenomenon is instead sensitive to real-world causal dependencies and not to exact content overlap. A group of participants rated the strength of the causal dependence between pairs of sentences. This measure is a near perfect (...) predictor of fallacious reasoning by an independent group of participants in illusory inference tasks with the same materials. In light of these results, we argue that all extant accounts of these deductive fallacies require non-trivial adjustments. Crucially, these novel _indirect_ illusory inferences from disjunction bear a structural similarity to seemingly unrelated _probabilistic reasoning_ problems, in particular the conjunction fallacy from the heuristics and biases literature. This structural connection was entirely obscure in previous work on these deductive problems, due to the theoretical and empirical focus on content overlap. We argue that this structural parallelism provides arguments against the need for rich descriptions and individuating information in the conjunction fallacy, and we outline a unified theory of deductive illusory inferences from disjunction and the conjunction fallacy, in terms of Bayesian confirmation theory. (shrink)

This essay examines two distinct modes of sonic disjunction in Rosanna Bruno and Anne Carson’s The Trojan Women: A Comic and Carson’s H of H Playbook. The Trojan Women shows how noticing sounds that are dislocated from expectations exposes hard truths about reality. H of H interrogates our “regular” mode of hearing other people and implies that there is a gap in how we can know others and know ourselves. Thus, though both are graphic texts, their power and effect (...) are nonetheless garnered also through the sounds they describe and conjure in the minds of their readers. (shrink)

A comparison of disjunctive theories of action and perception. The development of a theory of action that warrants the name, a disjunctive theory. On this theory, there is an exclusive disjunction: either an action or an event (in one sense). It follows that in that sense basic actions do not have events intrinsic to them.

Are there disjunctive properties? This question is important for at least two reasons. First, disjunctive properties are invoked in defense of certain philosophical theories, especially in the philosophy of mind. Second, the question raises the prior issue of what counts as a genuine property, a central concern in the metaphysics of properties. I argue here, on the basis of general considerations in the metaphysics of properties, that there are no disjunctive properties. Specifically, I argue that genuine properties must guarantee similarity-in-a-respect (...) among their instances, and must inhere in their bearers (two notions to be clarified). Disjunctive properties would fail both requirements. I compare the case of disjunctive properties with “mere Cambridge properties,” determinable properties, and functional properties, and show how my conception of properties remains compatible with determinables and functional properties while ruling out disjunctive and mere Cambridge properties. (shrink)

In Minker and Rajasekar (J Log Program 9(1):45–74, 1990), Minker proposed a semantics for negation-free disjunctive logic programs that offers a natural generalisation of the fixed point semantics for definite logic programs. We show that this semantics can be further generalised for disjunctive logic programs with classical negation, in a constructive modal-theoretic framework where rules are built from _claims_ and _hypotheses_, namely, formulas of the form \(\Box \varphi \) and \(\Diamond \Box \varphi \) where \(\varphi \) is a literal, respectively, (...) yielding a “base semantics” for general disjunctive logic programs. Model-theoretically, this base semantics is expressed in terms of a classical notion of logical consequence. It has a complete proof procedure based on a general form of the cut rule. Usually, alternative semantics of logic programs amount to a particular interpretation of nonclassical negation as “failure to derive.” The counterpart in our framework is to complement the original program with a set of hypotheses required to satisfy specific conditions, and apply the base semantics to the resulting set. We demonstrate the approach for the answer set semantics. The proposed framework is purely classical in mainly three ways. First, it uses classical negation as unique form of negation. Second, it advocates the computation of logical consequences rather than of particular models. Third, it makes no reference to a notion of preferred or minimal interpretation. (shrink)

This paper investigates young children's knowledge of scalar implicatures and downward entailment. In previous experimental work, we have shown that young children access the full range of truth-conditions associated with logical words in classical logic, including the disjunction operator, as well as the indefinite article. The present study extends this research in three ways, taking disjunction as a case study. Experiment 1 draws upon the observation that scalar implicatures (SIs) are cancelled (or reversed) in downward entailing (DE) linguistic (...) environments, e.g., in the scope of negation (Chierchia, 2000). Experiment 2 was designed to determine if scalar implicatures are used by children, like adults, to influence the interpretation of disjunction in non-DE contexts, yielding an implicature of exclusivity for disjunction. Whereas adult controls always rejected assertions of the form A or B in positive (non-DE) contexts in which assertions of the form A and B were also true, many children accepted assertions with disjunction in such contexts. To provide an interpretation to the findings from Experiment 2, a new experimental technique was devised and used in Experiment 3. The new technique presents pairs of assertions to children, who are asked to judge which assertion is a ‘better’ description of the context. The findings from Experiment 3 demonstrated children's awareness that A and B is more informative than A or B in positive contexts, where both statements are true. Taken together, the findings of Experiments 2 and 3 are compatible with the view that some children lack the computational resources to apply scalar implicatures when a single assertion is presented alone (see Reinhart, 1999). (shrink)

Many philosophers have been attracted to the idea of using the logical form of a true sentence as a guide to the metaphysical grounds of the fact stated by that sentence. This paper looks at a particular instance of that idea: the widely accepted principle that disjunctions are grounded in their true disjuncts. I will argue that an unrestricted version of this principle has several problematic consequences and that it’s not obvious how the principle might be restricted in order to (...) avoid them. My suggestion is that, instead of trying to restrict the principle, we should distinguish between metaphysical and conceptual grounds and take the principle to apply exclusively to the latter. This suggestion, if correct, carries over to other prominent attempts at using logical form as a guide to ground. (shrink)

A pigeon has been conditioned to peck at red objects and has also been conditioned to peck at triangular objects. The pigeon is now presented with a red triangle and pecks. In virtue of which of the object's properties did the pigeon peck? I argue that the disjunctive property "red or triangular" best answers this question and that this in turn gives us reason to admit such disjunctive properties to our ontology. I also show how the criterion for causal efficacy (...) that I employ, expressed in terms of counterfactual conditionals, works to preclude spurious disjunctive properties from counting as efficacious. (shrink)

We argue in favor of merely disjunctive effects, namely cases in which an event or fact, C, is not a cause of an effect, E1, and is also not a cause of a distinct effect, E2, and yet C is a cause of the disjunctive effect (E1 orE2). Disjunctive effects let us retain the additivity and the distributivity of causation. According to additivity, if C is a cause of E1 and C is a cause of E2, then C is a (...) cause of E1 and E2. According to distributivity, if C is a cause of E1 and E2, then C is a cause of E1 and C is a cause of E2. We draw an analogy between causation and intensional notions like believing, wanting, and owing, which also admit of merely disjunctive cases. We argue that both the Lewisian counterfactual account of causation (including its recent emendation by Sartorio) and the contrastive account of causation fail to properly account for this phenomenon. (shrink)

§1 The Disjunctive Conception of Experience Descartes was surely right that while normal waking experience, dreams and hallucinations are characteristically distinguished at a purely phenomenological level, — by contrasts of spatial perspective, coherence, clarity of image, etc., — it is not essential that they be so.1 What is it like for someone who dreams that he is sitting, clothed in his dressing gown, in front of his fire can in principle be subjectively indistinguishable from what it is like to perceive (...) that one is doing so, fully conscious and awake. The same holds for multi-sense hallucination and, it is assumed, would hold of the experience of an envatted brain in the usual postulated scenario. This thought — that normal perceptual experience allows in principle of perfect phenomenological counterfeit — is, to the best of my knowledge, nowhere seriously challenged in John McDowell's writings.2 What he rejects is an idea that builds upon and would be potentially explanatory of it: the Lockean idea that, as far as the states enjoyed by the experiencing subject are concerned, there is actually no generic distinction between dream, hallucination, and wakeful perception: — that one and the same type of state of consciousness is involved in all three cases, and that which (if any) of the three a particular occurrence of the type falls under is a matter of how it is caused. On this model, the distinction between Descartes' notional fully lucid dream and the corresponding raft of perceptions of his dressing-gowned, sedentary state is like that between a certain kind of sunburn and nettle rash. For Disjunctivism, however, the Lockean — as McDowell likes to say, “Highest Common Factor” — conception of perceptual experience and its potential counterfeits is a conceptual error. There is no single type of state of consciousness present in each of dreaming, perceiving and hallucinating, whose instances fall under one or other of those characterisations purely by virtue of their aetiology.. (shrink)

An operator of contraction for a belief set (a theory) can be obtained by assigning to it a belief base and an operator of partial meet contraction for that base. It is argued that closure of the base under disjunction is an intuitively reasonable condition. Axiomatic characterizations are given of the contractions of belief sets that can be generated by (various types of) partial meet contraction on disjunctively closed bases. The corresponding revision operators are also characterized. Finally, some results (...) are reported on operations on bases that are closed under material implication. (shrink)

This article examines the idea of disjunctive rights—an idea first suggested by Joel Feinberg and more recently advocated by Richard Arneson. Using a hypothetical scenario to bring forward a conflict between two rights that cannot be simultaneously fulfilled, the suggestion that the conflict can be solved by describing the right-holders as holding disjunctive rights—rights that involve, in a significant way, a disjunction—is scrutinized. Several interpretations of the idea of disjunctive rights are examined from the perspectives of the interest theory (...) and will theory of rights. Ultimately, the idea of disjunctive rights fails to provide an acceptable solution to the problem at hand, as each interpretation has unacceptable implications. This conclusion challenges the compossibilist thesis, according to which moral rights do not, ultimately, conflict. Alternatively, if one wishes to keep the possibility of compossibility and disjunctive rights, the mainstream theories of rights must be revised or rejected. (shrink)

The validity of argument by disjunctive syllogism has been denied by proponents of relevant and paraconsistent logic. DS is stigmatised for its role in inferences — most notably C.I. Lewis's derivation of that fallacy of irrelevance ex falso quodlibet — that involve both it and other rules of inference governing disjunction, or, to speak more precisely, other rules of inference taken to apply to the very same disjunction that obeys DS. In avoiding these inferences the road less travelled (...) is to deny the identity rather than to deny DS: what follows is, then, an exercise in disjoining disjunctions. (shrink)

We consider the problem of moral disjunction in professional and business activities from a virtue-ethical perspective. Moral disjunction arises when the behavioral demands of a role conflict with personal morality; it is an important problem because most people in modern societies occupy several complex roles that can cause this clash to occur. We argue that moral disjunction, and the psychological mechanisms that people use to cope with it, are problematic because they make it hard to pursue virtue (...) and to live with integrity. We present role coadunation as a process with epistemic and behavioral aspects that people can use to resolve moral disjunction with integrity. When role coadunation is successful, it enables people to live virtuous lives of appropriate narrative disunity and to honor their identity-conferring commitments. We show how role coadunation can be facilitated by interpretive communities and discuss the emergence and ideal features of those communities. (shrink)

This paper investigates propositional hyperintensionality in counterfactuals. It starts with a scenario describing two children playing on a seesaw and studies the truth-value predictions for counterfactuals by four different semantic theories. The theories in question are Kit Fine’s truthmaker semantics, Luis Alonso-Ovalle’s alternative semantics, inquisitive semantics and Paolo Santorio’s syntactic truthmaker semantics. These predictions suggest that the theories that distinguish more of a given set of intensionally equivalent sentences (Fine and Alonso-Ovalle’s) fare better than those that do not (inquisitive semantics (...) and Santorio’s). Then we investigate how inquisitive semantics and Santorio can respond to these results. They can respond to them by helping themselves to considerations from Hurford disjunctions, disjunctions whose disjuncts stand in an entailment relation to one another. I argue that considerations from Hurford disjunctions are ad hoc modifications merely to predict the expected results. I conclude that the scenarios suggest a need for more fine-grained theories of sentential meaning in general. (shrink)

The disjunction effect (Tversky and Shafir in Psychol Sci 3:305–309, 1992) occurs when decision makers prefer option x (versus y) when knowing that event A occurs and also when knowing that event A does not occur, but they refuse x (or prefer y) when not knowing whether or not A occurs. This form of incoherence violates Savage’s (Cognition 57:31–95, 1954) sure-thing principle, one of the basic axioms of the rational theory of decision-making. The phenomenon was attributed to a lack (...) of clear reasons for accepting an option (x) when the subjects are under uncertainty. Through a pragmatic analysis of the task and a consequent reformulation of it, we show that the effect does not depend on the presence of uncertainty, but on the introduction into the text-problem of a non-relevant goal. (shrink)

Reflection on skeptical scenarios in the philosophy of perception, made vivid in the arguments from illusion and hallucination, have led to the formulation of theories of the metaphysical and epistemological nature of perceptual experience. In recent times, the locus of the debate concerning the nature of perceptual experience has been the dispute between disjunctivists and common-kind theorists. Disjunctivists have held that there are substantial dissimilarities (either metaphysical or epistemological or both) between veridical perceptual experiences occurring when one perceives and perceptual (...) experiences involved in hallucination. Common-kind theorists have denied this. In this paper, I examine the nature of introspection – a faculty that has often been compared and contrasted to perception. I reflect on cases where introspection goes wrong in ways analogous to that in which our perceptual faculties can go wrong and formulate, what I take to be, an attractive theory of introspection. The cases that I focus on in which things go wrong are the case of zombies and the case of subjects with Anton’s syndrome. (Anton’s syndrome is a condition in which people who are blind claim that they can see.) I suggest that, just as it is possible to be a disjunctivist about perception, it is possible to be a disjunctivist about introspection. I argue that this is a good view of one type of introspection, namely, introspection of states that have phenomenal character, such as perceptual experiences. It has a good account to give of the cases in which such introspection seems to go wrong and it yields a plausible metaphysical and epistemological view of the nature of introspection. However, while I favour a disjunctive view of introspection, I do not favour a disjunctive view of perception. And, I suspect, that many disjunctivists about perception would not wish to condone my disjunctivist theory of introspection. I therefore go on to examine to what extent.. (shrink)

The relation between ex falso and disjunctive syllogism, or even the justification of ex falso based on disjunctive syllogism, is an old topic in the history of logic. This old topic reappears in contemporary logic since the introduction of minimal logic by Johansson. The disjunctive syllogism seems to be part of our general non-problematic inferential practices and superficially it does not seem to be related to or to depend on our acceptance of the frequently disputable ex falso rule. We know (...) that the acceptance of the ex falso is a sufficient condition for the acceptance of the disjunctive syllogism, but the interesting question is: is the ex falso a necessary condition for the acceptance of the disjunctive syllogism? The aim of the present paper is to discuss some possible ways to define systems that combines the preservation of the disjunctive syllogism with the rejection of the ex falso. (shrink)

Perceptual experiences are often divided into the following three broad categories: veridical perceptions, illusions, and hallucinations. For example, when one has a visual experience as of a red object, it may be that one is really seeing an object and its red colour (veridical perception), that one is seeing a green object (illusion), or that one is not seeing an object at all (hallucination). Many maintain that the same account should be given of the nature of the conscious experience that (...) occurs in each of these three cases. Those who hold a disjunctive theory of perception deny this. Disjunctivists typically reject the claim that the same kind of experience is common to all three cases because they hold views about the nature of veridical perception that are inconsistent with it. (shrink)