Given his hostility to intensional locutions, it is not surprising that Quine was suspicious of the subjunctive conditional. Although he admitted its usefulness as a heuristic device, in order to introduce dispositional terms, he held that it had no place in a finished scientific theory. In this paper I argue in support of something like Quine’s position. Many contemporary philosophers are unreflectively realist about subjunctives, regarding them as having objective truth values. I contest this. “Moderate realist” theorists, such as Lewis (...) and Stalnaker, admit that subjunctives are context-relative and often indeterminate; I argue, using some examples from the contemporary literature on conditionals, that these features are deeper and more widespread than they think. “Ultra-realist” theories, which deny any indeterminacy, are not credible. Hence subjunctives are unsuitable for certain purposes, in particular the description of mind-independent reality. (shrink)

A number of papers have argued in favour of the material account of indicative conditionals, but typically they either concentrate on defending the account from the charge that it has counterintuitive consequences, or else focus on some particular positive argument in favour of the theory. In this paper, I survey the various positive arguments that can be given, presenting simple versions where possible and showing the connections between them. I conclude with some methodological considerations.

We explore the prospects of a monist account of explanation for both non-causal explanations in science and pure mathematics. Our starting point is the counterfactual theory of explanation for explanations in science, as advocated in the recent literature on explanation. We argue that, despite the obvious differences between mathematical and scientific explanation, the CTE can be extended to cover both non-causal explanations in science and mathematical explanations. In particular, a successful application of the CTE to mathematical explanations requires us to (...) rely on counterpossibles. We conclude that the CTE is a promising candidate for a monist account of explanation in both science and mathematics. (shrink)

One finds in the systems of natural languages some explicit means of elaborating not only upon the directness of the causal relationship believed to exist between two events X and Y (i.e. some means of specifying just how inevitably event X gives or gave rise to event Y), but also some manner of indicating just who or what is understood to be the primary instigator of the caused event. The goal of the present paper is to explore these notions in (...) detail and arrive at a formal, logic-based means of capturing them. (shrink)

I propose a way of thinking aboout content, and a related way of thinking about ontological commitment. (This is part of a series of four closely related papers. The other three are ‘On Specifying Truth-Conditions’, ‘An Actualist’s Guide to Quantifying In’ and ‘An Account of Possibility’.).

The issues of just what laws of nature are and what makes statements law-like have been more discussed than advanced. After exploring the general area and uncovering some difficulties which, I suspect, make the case even knottier than generally imagined, I argue that certain resources available only to the theist---in particular, counterfactuals of God’s freedom---may provide the materials needed for constructing solutions.

The idea that there are features of or in our conscious experience that are, in some important sense, private has both a long history in philosophy and a large measure of intuitive attraction. Once this idea is in place, it will be very natural to assume that one can think and judge about one’s own private features. And it is then only a small step to the idea that we might communicate such thoughts and judgements about our respective private features (...) with each other. (shrink)

This paper investigates the implicative conditional, a connective intended to describe the logical behavior of an empirically defined class of natural language conditionals, also named implicative conditionals, which excludes concessive and some other conditionals. The implicative conditional strengthens the strict conditional with the possibility of the antecedent and of the contradictory of the consequent. $${p\Rightarrow q}$$ p ⇒ q is thus defined as $${\lnot } \Diamond {(p \wedge \lnot q) \wedge } \Diamond {p \wedge } \Diamond {\lnot q}$$ ¬ ◊ (...) ( p ∧ ¬ q ) ∧ ◊ p ∧ ◊ ¬ q. We explore the logical properties of this conditional in a reflexive normal Kripke semantics, provide an axiomatic system and prove it to be sound and complete for our semantics. The implicative conditional validates transitivity and contraposition, which we take to be integral parts of reasoning and communication. But it only validates restricted versions of strengthening the antecedent, right weakening, simplification, and rational monotonicity. Apparent counterexamples to some of these properties are explained as due to contextual factors. Finally, the implicative conditional avoids the paradoxes of material and strict implication, and validates some connexive principles such as Aristotle’s theses and weak Boethius’ thesis, as well as some highly entrenched principles of conditionals, such as conjunction of consequents, disjunction of antecedents, modus ponens, cautious monotonicity and cut. (shrink)

In some recent works, Crupi and Iacona have outlined an analysis of ‘if’ based on Chrysippus’ idea that a conditional holds whenever the negation of its consequent is incompatible with its antecedent. This paper presents a sound and complete system of conditional logic that accommodates their analysis. The soundness and completeness proofs that will be provided rely on a general method elaborated by Raidl, which applies to a wide range of systems of conditional logic.

According to Stalnaker’s Thesis, the probability of a conditional is the conditional probability. Under some mild conditions, the thesis trivialises probabilities and conditionals, as initially shown by David Lewis. This article asks the following question: does still lead to triviality, if the probability function in is replaced by a probability-like function? The article considers plausibility functions, in the sense of Friedman and Halpern, which additionally mimic probabilistic additivity and conditionalisation. These quasi probabilities comprise Friedman–Halpern’s conditional plausibility spaces, as well as (...) other known representations of conditional doxastic states. The paper proves Lewis’ triviality for quasi probabilities and discusses how this has implications for three other prominent strategies to avoid Lewis’ triviality: Adams’ thesis, where the probability function on the left in is replaced by a probability-like function, abandoning conditionalisation, where probability conditionalisation on the right in is replaced by another propositional update procedure and the approximation thesis, where equality in is replaced by approximation. The paper also shows that Lewis’ triviality result is really about ‘additiveness’ and ‘conditionality’. (shrink)

The variably strict analysis of conditionals does not only largely dominate the philosophical literature, since its invention by Stalnaker and Lewis, it also found its way into linguistics and psychology. Yet, the shortcomings of Lewis–Stalnaker’s account initiated a plethora of modifications, such as non-vacuist conditionals, presuppositional indicatives, perfect conditionals, or other conditional constructions, for example: reason relations, difference-making conditionals, counterfactual dependency, or probabilistic relevance. Many of these new connectives can be treated as strengthened or weakened conditionals. They are definable conditionals. (...) This article develops a technique to infer the logic for such definable conditionals from the known logic of the underlying defining conditional. The technique is applied to central examples. The results show that a large part of the zoo of conditionals arises from a basic conditional—a constant nucleus of the different contextual and conceptual variations of variably strict conditionals. (shrink)

A powerful argument against the counterfactual comparative account of harm is that it cannot distinguish harming from failing to benefit. In reply to this problem, I suggest a new account of harm. The account is a counterfactual comparative one, but it counts as harms only those events that make a person occupy his level of well-being at the world at which the event occurs. This account distinguishes harming from failing to benefit in a way that accommodates our intuitions about the (...) standard problem cases. In laying the groundwork for this account, I also demonstrate that rival accounts of harm are able to distinguish harming from failing to benefit only if, and because, they also appeal to the distinction between making upshots happen and allowing upshots to happen. One important implication of my discussion is that preserving the moral asymmetry between harming and failing to benefit requires a commitment to the existence of a metaphysical and moral distinction between making and allowing. (shrink)

This paper introduces and explores a conservative extension of inquisitive logic. In particular, weak negation is added to the standard propositional language of inquisitive semantics, and it is shown that, although we lose some general semantic properties of the original framework, such an enrichment enables us to model some previously inexpressible speech acts such as weak denial and ‘might’-assertions. As a result, a new modal logic emerges. For this logic, a Fitch-style system of natural deduction is formulated. The main result (...) of this paper is a theorem establishing the completeness of the system with respect to inquisitive semantics with weak negation. At the conclusion of the paper, the possibility of extending the framework to the level of first order logic is briefly discussed. (shrink)

A certain construal of the Gettier problem is offered, according to which this problem concerns the task of identifying the anti-luck condition on knowledge. A methodology for approaching this construal of the Gettier problem—anti-luck epistemology—is set out, and the utility of such a methodology is demonstrated. It is argued that a range of superficially distinct cases which are meant to pose problems for anti-luck epistemology are in fact related in significant ways. It is claimed that with these cases properly understood, (...) anti-luck epistemology is able to offer a suitable diagnosis of them which doesn’t threaten the necessity of the anti-luck condition for knowledge. (shrink)

A distinctive approach to the theory of knowledge is described, known as anti-luck epistemology. The goal of the paper is to consider whether there are specific features of this proposal that entails that it is committed to pragmatic encroachment, such that whether one counts as having knowledge significantly depends on non-epistemic factors. In particular, the plausibility of the following idea is explored: that since pragmatic factors play an essential role when it comes to the notion of luck, then according to (...) anti-luck epistemology they must likewise play an essential role in our understanding of knowledge as well. It is argued that once anti-luck epistemology is properly understood—where this means, in turn, having the right account of luck in play—then this putative entailment to pragmatic encroachment does not go through. (shrink)

The 3sg pronouns “he” and “she” impose descriptive gender conditions on their referents. These conditions are standardly analysed as presuppositions. Cooper argues that, when 3sg pronouns occur free, they have indexical presuppositions: the gender condition must be satisfied by the pronoun’s referent in the actual world. In this paper, we consider the behaviour of free 3sg pronouns in conditionals and focus on cases in which the pronouns’ gender presuppositions no longer seem to be indexical and project locally instead. We compare (...) these cases to previously reported shifty readings of indexicals in so-called “epistemic conditionals” :359–406, 2012) and propose a unified account of locally projected gender presuppositions and shifty indexicals based on the idea that indicative conditionals are Kaplanian monsters. (shrink)

In this paper we present labelled sequent calculi and labelled natural deduction calculi for the counterfactual logics CK + {ID, MP}. As for the sequent calculi we prove, in a semantic manner, that the cut-rule is admissible. As for the natural deduction calculi we prove, in a purely syntactic way, the normalization theorem. Finally, we demonstrate that both calculi are sound and complete with respect to Nute semantics [12] and that the natural deduction calculi can be effectively transformed into the (...) sequent calculi. (shrink)

We show that truth conditions for counterfactuals need not always be given in terms of a vague notion of similarity. To this end, we single out the important class of historical counterfactuals and give formally rigorous truth conditions for these counterfactuals, employing a partial ordering relation called "comparative closeness" that is defined in the framework of branching space-times. Among other applications, we provide a detailed analysis of counterfactuals uttered in the context of lost bets. In an appendix we compare our (...) theory with the branching space-times based reading of counterfactuals recently proposed by Belnap. (shrink)

The arbitrariness of a signal has long been seen as a theoretically important but difficult to pin down notion. In this article, we suggest there are at least two different notions of arbitrariness at play in philosophical and scientific debates concerning the use of arbitrary signals, and work towards improved analyses of both. We then consider how these different types of arbitrariness can co-occur and come apart. Finally, we examine the connections between these two types of arbitrariness and the cognitive (...) complexity of signal users with an eye towards better evaluating one possible form of human-nonhuman communicative continuity. We show that each type of arbitrariness bears its own nuanced relationship to cognitive complexity, demonstrating the theoretical importance of keeping these two notions separate. (shrink)

According to the Counterfactual Comparative Account of harm and benefit, an event is overall harmful for a subject to the extent that this subject would have been better off if it had not occurred. In this paper we present a challenge for the Counterfactual Comparative Account. We argue that if physical processes are chancy in the manner suggested by our best physical theories, then CCA faces a dilemma: If it is developed in line with the standard approach to counterfactuals, then (...) it delivers that the value of any event for a subject is indeterminate to the extreme, ranging from terribly harmful to highly beneficial. This problem can only be avoided by developing CCA in line with theories of counterfactuals that allow us to ignore a-typical scenarios. Doing this generates a different problem: when the actual world is itself a-typical we will sometimes get the result that the counterfactual nonoccurrence of an actual benefit is itself a benefit. An account of overall harm bearing either of these two implications is deficient. Given the general aspiration to account for deprivational harms and the dominance of the Counterfactual Comparative Account in this respect, theorists of harm and benefit face a deadlock. (shrink)

I argue in favor of a certain connection between knowledge and the permissibility of action. On this approach, we do not think of the relation between those notions as reflecting a universal epistemic principle. Instead, we think of it as something resembling a platitude from folk psychology. With the help of some elementary tools from the logic of normativity and counterfactuals, I attempt to establish the connection by deriving it from more elementary principles. The new formulation involves a ceteris paribus (...) clause. Though it is often difficult to specify the exact content of a ceteris paribus clause, we will see that our clause is derived from a descriptive generalization with independent motivation. (shrink)

In this paper, I propose and defend a pair of necessary conditions on evidence-based knowledge which bear resemblance to the troubled sensitivity principles defended in the philosophical literature. We can think of the traditional principles as simple but inaccurate approximations of the new proposals. Insofar as the old principles are intuitive and used in scientific and philosophical contexts, but are plausibly false, there’s a real need to develop precise and correct formulations. These new renditions turned out to be more cautious, (...) so they won’t be able to do everything the old principled promised they could. For example, they respect closure for knowledge. But these sober formulations, or something like them, might be the best that we can do with respect to sensitivity. And there’s value in understanding the limits to these types of principles. (shrink)

Safety, as discussed in contemporary epistemology, is a feature of true beliefs. Safe beliefs, when formed by the same method, remain true in close-by possible worlds. I argue that our beliefs being safely true serves no recognisable epistemic interest and, thus, that this notion of safety should play no role in epistemology. Epistemologists have been misled by failing to distinguish between a feature of beliefs — being safely true — and a feature of believers, namely being safe from error. The (...) latter is central to our epistemic endeavours: we want to be able to get right answers, whatever they are, to questions of interest. I argue that we are sufficiently safe from error (in some relevant domain) by being sufficiently sensitive (to relevant distinctions). (shrink)

This open access book is a superb collection of some fifteen chapters inspired by Schroeder-Heister's groundbreaking work, written by leading experts in the field, plus an extensive autobiography and comments on the various contributions by Schroeder-Heister himself. For several decades, Peter Schroeder-Heister has been a central figure in proof-theoretic semantics, a field of study situated at the interface of logic, theoretical computer science, natural-language semantics, and the philosophy of language. -/- The chapters of which this book is composed discuss the (...) subject from a rich variety of angles, including the history of logic, the proper interpretation of logical validity, natural deduction rules, the notions of harmony and of synonymy, the structure of proofs, the logical status of equality, intentional phenomena, and the proof theory of second-order arithmetic. All chapters relate directly to questions that have driven Schroeder-Heister's own research agenda and to which he has made seminal contributions. The extensive autobiographical chapter not only provides a fascinating overview of Schroeder-Heister's career and the evolution of his academic interests but also constitutes a contribution to the recent history of logic in its own right, painting an intriguing picture of the philosophical, logical, and mathematical institutional landscape in Germany and elsewhere since the early 1970s. The papers collected in this book are illuminatingly put into a unified perspective by Schroeder-Heister's comments at the end of the book. Both graduate students and established researchers in the field will find this book an excellent resource for future work in proof-theoretic semantics and related areas. (shrink)

Decision theory and folk psychology both purport to represent the same phenomena: our belief-like and desire- and preference-like states. They also purport to do the same work with these representations: explain and predict our actions. But they do so with different sets of concepts. There's much at stake in whether one of these two sets of concepts can be accounted for with the other. Without such an account, we'd have two competing representations and systems of prediction and explanation, a dubious (...) dualism. Folk psychology structures our daily lives and has proven fruitful in the study of mind and ethics, while decision theory is pervasive in various disciplines, including the quantitative social sciences, especially economics, and philosophy. My interest is in accounting for folk psychology with decision theory -- in particular, for believe and wanting, which decision theory omits. Many have attempted this task for belief. (The Lockean Thesis says that there is such an account.) I take up the parallel task for wanting, which has received far less attention. I propose necessary and sufficient conditions, stated in terms of decision theory, for when you're truly said to want; I give an analogue of the Lockean Thesis for wanting. My account is an alternative to orthodox accounts that link wanting to preference (e.g. Stalnaker (1984), Lewis (1986)), which I argue are false. I argue further that want ascriptions are context-sensitive. My account explains this context-sensitivity, makes sense of conflicting desires, and accommodates phenomena that motivate traditional theses on which 'want' has multiple senses (e.g. all-things-considered vs. pro tanto). (shrink)

Abduction is considered the most powerful, but also the most controversially discussed type of inference. Based on an analysis of Peirce’s retroduction, Lipton’s Inference to the Best Explanation and other theories, a new theory of abduction is proposed. It considers abduction not as intrinsically explanatory but as intrinsically conditional: for a given fact, abduction allows one to infer a fact that implies it. There are three types of abduction: Selective abduction selects an already known conditional whose consequent is the given (...) fact and infers that its antecedent is true. Conditional-creative abduction creates a new conditional in which the given fact is the consequent and a defined fact is the antecedent that implies the given fact. Propositional-conditional-creative abduction assumes that the given fact is implied by a hitherto undefined fact and thus creates a new conditional with a new proposition as antecedent. The execution of abductive inferences is specified by theory-specific patterns. Each pattern consists of a set of rules for both generating and justifying abductive conclusions and covers the complete inference process. Consequently, abductive inferences can be formalised iff the whole pattern can be formalised. The empirical consistency of the proposed theory is demonstrated by a case study of Semmelweis' research on puerperal fever. (shrink)

In this article, I aim at problematizing the implied idea of causality in cognitive evaluations of horizontal justice events. I will draw on theories about retrospective sensemaking and its cognitive foundation in counterfactual belief formation. Issues related to horizontal or intraunit unfairness emerge in situations in which the actions of one employee influence the outcome of another due to relational interdependence. The authors of theories about horizontal unfairness have continued the traditional distinction between the three facets of justice, procedural, distributive, (...) and interactional. However, might employee A blame employee B because she (B) obtained qualitative (e.g., non-monetary appraisal) or quantitative (e.g., monetary compensation) recognition even though the latter did not, directly at least, bring about the event. The problem here is one of causality which asks the question, Can A be blamed by B for bringing about the event of outcome difference? While blame in evaluations of vertical justice certainly presumes causal agency, it might be questioned whether the same goes for horizontal unfairness. Counterfactual belief formation enables a step into the cognitive and retrospective nature of evaluations of horizontal justice events centered on the counterfactual belief “had the unfavorable event X not occurred, another and more favorable event X1 would have occurred.” This is related to the distance between the actual X and the potential event state X), in the sense that the closer the two appear, the more convincing becomes A’s belief to himself. The underlying causality of rewarding processes, however, states that some third party introduces the recognition, for example, a manager, and, therefore, B did not bring about the reward event, the third party did. It seems, then, that to understand this, we should take into consideration: 1) the formation of counterfactual beliefs and 2) the causality of blame. The article concludes that, due to the underlying causality of rewarding processes, one might solely consider one facet of horizontal justice, interactional horizontal justice. However, tapping into the phenomenological dimension of morality might allow one also to address the moral nature of distributive and procedural facets of horizontal justice as the experience of the psychosocial fabric of social reality related with feeling either “as if” one is being treated unfairly or “as if” one is treating others unfairly. (shrink)

In this paper I assume that syntactic structures contain items that function as variables over possible worlds (or things like possible worlds). I show that in certain syntactic positions we can use some variables but not other. I accordingly motivate a "binding theory" for the items that occupy these positions, and I discuss some consequences of this binding theory.

This article is an extended critical study of Robert C. Stalnaker, 'Inquiry' (Cambridge, MA: MIT Press, 1984).

This paper begins by considering Dummett's justificationist treatment of statements about the past in his book Truth and the Past (2004). Contrary to Dummett's position, there is no way of applying the intuitionistic distinction in the arithmetical case between direct and indirect methods of establishing a content to the case of past-tense statements. Attempts to do so either give the wrong truth conditions, or rely on notions not available to a justificationist position. A better, realistic treatment makes ineliminable use of (...) identity of state in its positive account of understanding of the past tense; this account can also be applied to other subject matters besides the past. A theory is developed of how realists should conceive of the relation between meaning and evidence. Points from this discussion are used in criticism of Wright's minimalist conception of truth. Three grades of possible involvement of truth and reference in a substantive theory of intentional content are distinguished, and reasons are given for thinking that a range of contents involve the highest degree of involvement of reference and truth in their substantive individuation. (shrink)

Traditional procedures for rational updating fail when it comes to self-locating opinions, such as your credences about where you are and what time it is. This paper develops an updating procedure for rational agents with self-locating beliefs. In short, I argue that rational updating can be factored into two steps. The first step uses information you recall from your previous self to form a hypothetical credence distribution, and the second step changes this hypothetical distribution to reflect information you have genuinely (...) learned as time has passed. While the second step resembles traditional procedures of updating by conditionalization, the first is best understood by analogy to traditional models of how agents transmit self-locating opinions through ordinary interpersonal communication. (shrink)

It is often thought that the test for whether an indicative conditional is assertible is to first suppose the antecedent and then check to see if the consequent is probable on that supposition. Call this procedure the “Ramsey Test”. Some influential accounts of indicative conditionals hold that the Ramsey Test works because indicative conditionals are used to express a high credence in the consequent conditional on the antecedent. In this paper I will argue that a different expressivist account, one inspired (...) by Brandom can handle a wider range of phenomena. In particular, it does a better job explaining how conditionals function in modus tollens arguments. I will end by discussing how the account proposed here goes beyond Brandom’s own work on logic and hermeneutics. Of particular importance is the role played by a conversational common ground, distinct from the commitments of the interpreter and interpreted. (shrink)

The idea that sentences can be closer or further apart in meaning is highly intuitive. Not only that, it is also a pillar of logic, semantic theory and the philosophy of science, and follows from other commitments about similarity. The present paper proposes a novel way of comparing the ‘distance’ between two pairs of propositions. We define ‘\ is closer in meaning to \ than \ is to \’ and thereby give a precise account of comparative propositional similarity facts. Notably, (...) our definition eschews metric assumptions, which are unrealistic in most applications of interest. (shrink)

Certain measurement-related constructions impose a requirement that the measure function used track the part-whole structure of the domain of measurement, so that a given entity or eventuality must have a larger measurement in the chosen dimension than any of its salient proper parts. I provide evidence from English and Chinese that these constructions can be used to measure the intensity of mental states like hatred and love, indicating that in the natural language ontology of such states, intensity correlates with part-whole (...) structure. A natural language metaphysics of psychological intensity meeting this requirement is then developed and integrated into the semantics. Further complications arise when looking at attitudes like want, wish, and regret, which also permit measurements of intensity in the relevant constructions. To account for such attitudes, the ontology and semantics are then enriched in a way that integrates ordering and quantification over possible worlds into the part-whole structure of attitude states, so that even in these more complicated cases, the constructions at hand have a unified compositional semantics. (shrink)

E. J. Lowe argues that the mental event token cannot be identical to the complex neural event token for they have different counterfactual properties. If the mental event had not occurred, the behavior would not have ensued, while if the neural event had not occurred, the behavior would have ensued albeit slightly differently. Lowe's argument for the neural counterfactual relies on standard possible world semantics, whose evaluation of such counterfactuals is problematic. His argument for the mental counterfactual relies on a (...) premise that is plausibly false. My arguments support other counterfactuals, which are consistent with identity theories. (shrink)

Enthymemes are traditionally defined as arguments in which some elements are left unstated. It is an empirical fact that enthymemes are both enormously frequent and appropriately understood in everyday argumentation. Why is it so? We outline an answer that dispenses with the so called "principle of charity", which is the standard notion underlying most works on enthymemes. In contrast, we suggest that a different force drives enthymematic argumentation—namely, parsimony, i.e. the tendency to optimize resource consumption, in light of the agent's (...) goals. On this view, the frequent use of enthymemes does not indicate sub-optimal performance of arguers, requiring appeals to charity for their redemption. On the contrary, it is seen as a highly adaptive argumentation strategy, given the need of everyday reasoners to optimize their cognitive resources. Considerations of parsimony also affect enthymeme reconstruction, i.e. the process by which the interpreter makes sense of the speaker's enthymemes. Far from being driven by any pro-social cooperative instinct, interpretative efforts are aimed at extracting valuable information at reasonable costs from available sources. Thus, there is a tension between parsimony and charity, insofar as the former is a non-social constraint for self-regulation of one's behaviour, whereas the latter implies a pro-social attitude. We will argue that some versions of charity are untenable for enthymeme interpretation, while others are compatible with the view defended here, but still require parsimony to expose the ultimate reasons upon which a presumption of fair treatment in enthymeme reconstruction is founded. (shrink)

The two main psychological theories of the ordinary conditional were designed to account for inferences made from assumptions, but few premises in everyday life can be simply assumed true. Useful premises usually have a probability that is less than certainty. But what is the probability of the ordinary conditional and how is it determined? We argue that people use a two stage Ramsey test that we specify to make probability judgements about indicative conditionals in natural language, and we describe experiments (...) that support this conclusion. Our account can explain why most people give the conditional probability as the probability of the conditional, but also why some give the conjunctive probability. We discuss how our psychological work is related to the analysis of ordinary indicative conditionals in philosophical logic. (shrink)

We describe a logic of preference in which modal connectives reflect reasons to desire that a sentence be true. Various conditions on models are introduced and analyzed.

It is customary in current philosophy of time to distinguish between an A- (or tensed) and a B- (or tenseless) theory of time. It is also customary to distinguish between an old B-theory of time, and a new B-theory of time. We may say that the former holds both semantic atensionalism and ontological atensionalism, whereas the latter gives up semantic atensionalism and retains ontological atensionalism. It is typically assumed that the B-theorists have been induced by advances in the philosophy of (...) language and related A-theorists’ criticisms to acknowledge that semantic atensionalism can hardly stand, but have also maintained that what is essential for the B-theory is ontological atensionalism, which can be independently defended. Here it is argued that the B-theorists have been too quick in abandoning semantic atensionalism: they can still cling to it. (shrink)

In this paper we focus on theorem proving for conditional logics. First, we give a detailed description of CondLean, a theorem prover for some standard conditional logics. CondLean is a SICStus Prolog implementation of some labeled sequent calculi for conditional logics recently introduced. It is inspired to the so called “lean” methodology, even if it does not fit this style in a rigorous manner. CondLean also comprises a graphical interface written in Java. Furthermore, we introduce a goal-directed proof search mechanism, (...) derived from the above mentioned sequent calculi based on the notion of uniform proofs. Finally, we describe GOALDUCK, a simple SICStus Prolog implementation of the goal-directed calculus mentioned here above. Both the programs CondLean and GOALDUCK, together with their source code, are available for free download at. (shrink)

David Lewis has recently developed the notion of conversational scorekeeping as a way of explaining the acceptability of utterances in various contexts and the manner in which this acceptability changes in a rule-governed manner. I will expand Lewis's discussion by showing how the acceptibility of conditionals is linked to conversational score. In particular, I will argue that at least one controversial issue concerning the logic of conditionals, the interpretation and use of conditionals with disjunctive antecedents, may be resolved by applying (...) Lewis's notion of an accommodation rule for conversational scorekeeping. (shrink)

The semantics Vann McGee gives for his 1989 conditional logic is based on Stalnaker’s 1968 semantics but replaces the familiar concept of truth at a world with the novel concept of truth under a hypothesis. Developed here is a semantics of the standard type, in which sentences are true at worlds, only with additional constraints imposed on the accessibility relation and the selection function. McGee conditionals of the form A ⇒ X are translated into Stalnaker conditionals of the form \A (...) > X. An interpretation of the semantics is provided, and a few implications for the theory of indicative conditionals and their probabilities are noted. (shrink)

I give a semantics for a logic with two pairs of doxastic modals and an indicative conditional connective that all nest without restriction. Sentences are evaluated as accepted, rejected, or neither. Certainty is the necessity-like modality of acceptance. Inferences may proceed from premises that are certain, or merely accepted, or a mix of both. This semantic setup yields some striking results. Notably, the existence of inferences that preserve certainty but not acceptance very directly implies both failure of modus ponens for (...) the indicative conditional in the logic of acceptance and failure of the deduction theorem for the material conditional in the logic of certainty. The latter failure dissolves, in the logic of certainty, the much - discussed tension between modus ponens and the law of import-export. (shrink)