For centuries, inconsistencies were seen as a hindrance to good reasoning, and their role in the sciences was ignored. In recent years, however, logicians as well as philosophers and historians have showed a growing interest in the matter. Central to this change were the advent of paraconsistent logics, the shift in attention from finished theories to construction processes, and the recognition that most scientific theories were at some point either internally inconsistent or incompatible with other accepted findings. The new interest (...) gave rise to important questions. How is `logical anarchy' avoided? Is it ever rational to accept an inconsistent theory? In what sense, if any, can inconsistent theories be considered as true? The present collection of papers is the first to deal with this kind of questions. It contains case studies as well as philosophical analyses, and presents an excellent overview of the different approaches in the domain. (shrink)

The concept of measuring inconsistency in information was developed by John Grant in a 1978 paper in the context of first-order logic. For more than 20 years very little was done in this area until in the early 2000s a number of AI researchers started to formulate new inconsistency measures primarily in the context of propositional logic knowledge bases. The aim of this volume is to survey what has been done so far, to expand inconsistency measurement to (...) other formalisms, to connect it with related topics, and to provide ideas for further research in a topic that is particularly relevant now in view of the many inconsistencies in the massive amount of information available. The book contains 11 chapters. The first chapter, by John Grant, gives his original motivation for starting this field, explains why it was formulated in a highly mathematical manner, presents important material that was omitted from the original paper, and provides ideas about the use of dimensions in measuring inconsistency. The second chapter, by Matthias Thimm, is a survey that covers most of the research on inconsistency measures up to 2017. The other 9 chapters, all by experts either in inconsistency measures, or in the topic under consideration, or both, connect inconsistency measures with argumentation, disjunctive logic programming, fuzzy logic systems, modal logics, multiset representation, paraconsistent consequence, probabilistic logic, relational databases, and spatio-temporal databases."-- back cover. (shrink)

This is a philosophical and historical investigation of the role of inconsistent representations of the same scientific phenomenon. The logical difficulties associated with the simultaneous application of inconsistent models are discussed. Internally inconsistent scientific proposals are characterized as structures whose application is necessarily tied to the confirming evidence that each of its components enjoys and to a vision of the general form of the theory that will resolve the inconsistency. Einstein's derivation of the black body radiation law is used (...) as an example application of such a strategy and is contrasted with planck's derivation. (shrink)

It has recently been argued by Davey (2014) that inconsistency is never tolerated in science, but only discretely isolated. But when talking about inconsistencies in science, not much attention has been paid to the inconsistencies between theory and observation. Here I will argue that inconsistency toleration actually takes place in science, and that when we examine actual inconsistent theories, inconsistencies between theory and observation look anything but homogeneous. I will argue, appealing to certain properties of empirical theories, especially (...) holism, that at least two sub-types of inconsistencies regarding theory and observation can be distinguished: those that satisfy a criterion of observational independence and those that do not. (shrink)

Peter Vickers examines 'inconsistent theories' in the history of science--theories which, though contradictory, are held to be extremely useful. He argues that these 'theories' are actually significantly different entities, and warns that the traditional goal of philosophy to make substantial, general claims about how science works is misguided.

I erect a framework within the semantic view of theories for explaining the empirical success of internally inconsistent models and theories, with scientific realism in mind. The framework is an instance of the ‘content-driven’ approach to inconsistency, advocated by both Norton (Philos Sci 54:327–350, 1987) and Smith (Stud Hist Philos Sci 19:429–445, 1988a, In: Fine A, Leplin J (eds) PSA1988, 1988b), whose ideas my analysis aims to clarify and substantiate.

William Simkulet has recently criticised Colgrove et al’s defence against what they have called inconsistency arguments—arguments that claim opponents of abortion (OAs) act in ways inconsistent with their underlying beliefs about human fetuses (eg, that human fetuses are persons at conception). Colgrove et al presented three objections to inconsistency arguments, which Simkulet argues are unconvincing. Further, he maintains that OAs who hold that the fetus is a person at conception fail to act on important issues such as the (...) plight of frozen embryos, poverty and spontaneous abortion. Thus, they are morally negligent. In response, we argue that Simkulet has targeted a very narrow group of OAs, and so his criticisms are inapplicable to most OAs. We then explain why his responses to each of Colgrove et al’s objections do not succeed, even for this restricted group. Finally, we note that Simkulet fails to provide evidence for his claims regarding OAs’ supposed failures to act, and we show that OAs veritably do invest resources into these important issues. We conclude that Colgrove et al’s reasons for rejecting inconsistency arguments (en masse) remain intact. (shrink)

This paper discusses a conception of physics as a collection of theories that, from a logical point of view, is inconsistent. It is argued that this logical conception of the relations between physical theories is too crude. Mathematical subtleties allow for a much more nuanced and sophisticated understanding of the relations between different physical theories.

In this paper we discuss the process of building a joint probability distribution from an input set of low-dimensional probability distributions. Since the solution of the problem for a consistent input set of probability distributions is known we concentrate on a setup where the input probability distributions are inconsistent. In this case the iterative proportional fitting procedure (IPFP), which converges in the consistent case, tends to come to cycles. We propose a new algorithm that converges even in inconsistent case. The (...) important property of the algorithm is that it can be efficiently implemented exploiting decomposability of considered distributions. (shrink)

In this work, the first of a series, we study the nature of informal inconsistency in physics, focusing mainly on the foundations of quantum theory, and appealing to the concept of quasi-truth. We defend a pluralistic view of the philosophy of science, grounded on the existence of inconsistencies and on quasi-truth. Here, we treat only the ‘classical aspects’ of the subject, leaving for a forthcoming paper the ‘non-classical’ part.

Inconsistency robustness is information system performance in the face of continually pervasive inconsistencies---a shift from the previously dominant paradigms of inconsistency denial and inconsistency elimination attempting to sweep them under the rug. Inconsistency robustness is a both an observed phenomenon and a desired feature: Inconsistency Robustness is an observed phenomenon because large information-systems are required to operate in an environment of pervasive inconsistency. Inconsistency Robustness is a desired feature because we need to improve (...) the performance of large information system. This volume has revised versions of refereed articles and panel summaries from the first two International Symposia on Inconsistency Robustness conducted under the auspices of the International Society for Inconsistency Robustness. The articles are broadly based on theory and practice, addressing fundamental issues in inconsistency robustness. The field of Inconsistency Robustness aims to provide practical rigorous foundations for computer information systems dealing with pervasively inconsistent information.". (shrink)

Conventional economic theory assumes that agents should be consistent across decisions. However, it is often observed that experimental subjects fail to report consistent preferences. So far, these inconsistencies are almost always examined singly. We thus wonder whether the more inconsistent individuals in one task are also more inconsistent in other tasks. We propose an experiment in which subjects are asked to report their preferences over risky bets so as to obtain, for each subject, three measures of inconsistencies: classical preference reversals, (...) framing effects and preference instability. In line with previous experimental findings, subjects are largely inconsistent according to each of these three measures and there are considerable individual differences. The main result is that we find no correlation among these three measures of inconsistency. (shrink)

This paper introduces new logical systems which axiomatize a formal representation of inconsistency (here taken to be equivalent to contradictoriness) in classical logic. We start from an intuitive semantical account of inconsistent data, fixing some basic requirements, and provide two distinct sound and complete axiomatics for such semantics, LFI1 and LFI2, as well as their first-order extensions, LFI1* and LFI2*, depending on which additional requirements are considered. These formal systems are examples of what we dub Logics of Formal (...) class='Hi'>Inconsistency (LFI) and form part of a much larger family of similar logics. We also show that there are translations from classical and paraconsistent first-order logics into LFI1* and LFI2*, and back. Hence, despite their status as subsystems of classical logic, LFI1* and LFI2* can codify any classical or paraconsistent reasoning. (shrink)

A number of inconsistencies are pointed out in the conservation equations that describe the tensor bilinear densities for the conserved properties of spin-1/2 spinor fields. All the inconsistencies are related to the description of the spin density, and the origin of these difficulties is discussed.

ABSTRACT To have a coherent picture of Wang Chong’s Lunheng is difficult. Some of Lunheng’s chapters obviously show Wang’s hostility to a large part of the folklore (including the social institutions based on it) and traditional philosophical texts. In some other chapters, however, Wang appears to be more sympathetic to the social institutions related to folk religious beliefs. Esther Sunkyung Klein & Colin Klein attempt to explain this prima facie inconsistency in terms of ‘piecemeal non-reductionism’, which roughly means that (...) Wang would take any testimonial belief for granted until he can find a defeater of such a belief. But this explanation merely depicts Wang as a defeater-seeker rather than a thinker looking for philosophical grounds of his claims in a more positive manner. In contrast, in this paper, I intend to attribute the following epistemological thesis to Wang: A testimonial belief taken from classics or folklore will be judged as unjustified if the knowledge attributor finds a non-negligible defeater of it, and such an attributor would feel more sympathetic to the target belief if it can be at least prima facie justified in the light of analogical reasoning. (shrink)

Most opposition to induced abortion turns on the belief that human fetuses are persons from conception. On this view, the moral status of the fetus alone requires those in a position to provide aid—gestational mothers—to make tremendous sacrifices to benefit the fetus. Recently, critics have argued that this pro-life position requires more than opposition to induced abortion. Pro-life theorists are relatively silent on the issues of spontaneous abortion, surplus in vitro fertilisation human embryos, and the suffering and death of born (...) persons due to lack of access to food, shelter and medical care. Colgrove et al call such arguments inconsistency arguments, arguing they ‘do not matter’ and mischaracterise them as ad hominem attacks. Here, I argue these are better understood as moral dilemmas. While some critics argue pro-life inaction is evidence that they do not really believe human fetuses are persons, I contend this inaction is likely the result of resolvable confusion rather than moral negligence. (shrink)

Though the social world is real and objective, the way that social facts arise out of other facts is in an important way shaped by human thought, talk and behaviour. Building on recent work in social ontology, I describe a mechanism whereby this distinctive malleability of social facts, combined with the possibility of basic human error, makes it possible for a consistent physical reality to ground an inconsistent social reality. I explore various ways of resisting the prima facie case for (...) social inconsistency. I conclude, however, that the prima facie case survives scrutiny, and draw out some of the ramifications. (shrink)

In theorizing about racial pejoratives, an initially attractive view is that pejoratives have the same reference as their “neutral counterparts”. Call this the identity thesis. According to this thesis, the terms “kike” and “Jew”, for instance, pick out the same set of people. To be a Jew just is to be a kike, and so to make claims about Jews just is to make claims about kikes. In this way, the two words are synonymous, and so make the same contribution (...) to the truth-conditions of sentences containing them. While the fundamental claim for the identity thesis that Jews are kikes sounds anti-semitic, it need not be actually anti-semitic. The identity thesis is usually bolstered with the further claim that the pejorative aspect of “kike” and other such terms is located elsewhere than in truth-conditional content, so what makes “kike” a bad word is a non-truth-conditional association with anti-semitism that is not shared with the word “Jew”. The exact nature and location of the negative moral content of pejoratives is a matter of some dispute among identity theorists. But whatever the intuitive appeal of the identity theory for those persuaded by such views, it is nevertheless inconsistent. (shrink)

Even when inconsistencies are present in our premise set, we can sensibly distinguish between good and bad arguments relying on these premises. In making this distinction, the inconsistency-adaptive approach of Batens strikes a particularly nice balance between inconsistency-tolerance and inferential strength. In this paper, we use the machinery of Batens’ approach to extend the paraconsistent approach to dialogical logic as developed by Rahman and Carnielli. In bringing these frameworks closer together, we obtain a dynamic mechanism for the systematic (...) study of dialogues in which two parties exchange arguments over a central claim, in the possible presence of inconsistencies. (shrink)

The article is an extended critical discussion of Kevin Scharp’s Replacing Truth. Scharp’s case for the claim that the concept of truth is inconsistent is criticized, and so is his case for the claim that the concept of truth must be replaced because of its inconsistency.

The paper examines philosophical issues that arise in contexts where one has many different models for treating the same system. I show why in some cases this appears relatively unproblematic (models of turbulence) while others represent genuine difficulties when attempting to interpret the information that models provide (nuclear models). What the examples show is that while complementary models needn’t be a hindrance to knowledge acquisition, the kind of inconsistency present in nuclear cases is, since it is indicative of a (...) lack of genuine theoretical understanding. It is important to note that the differences in modeling do not result directly from the status of our knowledge of turbulent flows as opposed to nuclear dynamics—both face fundamental theoretical problems in the construction and application of models. However, as we shall, the ‘problem context(s)’ in which the modeling takes plays a decisive role in evaluating the epistemic merit of the models themselves. Moreover, the theoretical difficulties that give rise to inconsistent as opposed to complementary models (in the cases I discuss) impose epistemic and methodological burdens that cannot be overcome by invoking philosophical strategies like perspectivism, paraconsistency or partial structures. (shrink)

Buchanan highlighted the inconsistencies that arise when public services are financed by general taxation. Citizens increase their demand for services, even though citizens are reticent to increase taxation. Buchanan invited readers to explore the impact of different assumptions of politicians’ behaviour. In this chapter, attention focuses on the way that vote maximising governments are likely to respond to the divorce between receipt and payment for services. Buchanan illustrated his analysis with reference to the National Health Service in the UK. Predictions (...) are tested with reference to the pattern of excess demand in the National Health Service between 1970 and 2012. (shrink)

In this paper, I will characterize a new class of inconsistency-adaptive logics, namely inconsistency-adaptive modal logics. These logics cope with inconsistencies in a modal context. More specifically, when faced with inconsistencies, inconsistency-adaptive modal logics avoid explosion, but still allow the derivation of sufficient consequences to adequately explicate the part of human reasoning they are intended for.

Opponents of abortion are commonly said to be inconsistent in their beliefs or actions, and to fail in their obligations to prevent the deaths of embryos and fetuses from causes other than induced...

The paper establishes the general structure of the inconsistent models of arithmetic of [7]. It is shown that such models are constituted by a sequence of nuclei. The nuclei fall into three segments: the first contains improper nuclei: the second contains proper nuclei with linear chromosomes: the third contains proper nuclei with cyclical chromosomes. The nuclei have periods which are inherited up the ordering. It is also shown that the improper nuclei can have the order type of any ordinal, of (...) the rationals, or of any other order type that can be embedded in the rationals in a certain way. (shrink)

Graham Priest introduces an informal but presumably rigorous and sharp ‘provability predicate’. He argues that this predicate yields inconsistencies, along the lines of the paradox of the Knower. One long-standing claim of Priest’s is that a dialetheist can have a complete, decidable, and yet sufficiently rich mathematical theory. After all, the incompleteness theorem is, in effect, that for any recursive theory A, if A is consistent, then A is incomplete. If the antecedent fails, as it might for a dialetheist, then (...) the consequent may also fail to hold. One somewhat friendly purpose of my ‘Incompleteness and inconsistency’ was to improve the technical situation for the dialetheist, eschewing reliance on an informal provability predicate. Another, less friendly purpose was to bring out what I took to be some untoward consequences of the situation. It seems that Priest accepted at least some of the improvements that I attempted. In the second edition of In contradiction, he responded to the alleged untoward consequences. One purpose of this note is to revisit the technical and philosophical situation. There were some errors in my original presentation, brought out by discussion with Priest and by Hartry Field’s analysis of the second incompleteness theorem in such contexts. A second task here is to present a sort of Curry version of the Gödel incompleteness situation. I tentatively conclude that even for a dialetheist, an interesting and complete theory is not as easy to come by as it may look—at least not for theories of arithmetic that are plausible for a dialetheist. (shrink)

The relationship between inconsistency and Lehrerian coherence is scrutinized. Like most coherence theorists of epistemic justification, Lehrer contends that consistency is necessary for coherence. Despite this contention, minimally inconsistent belief-sets prove coherent and rationally acceptable on Lehrer's account of coherence. Lehrer is left with the following dilemma: If consistency is necessary for coherence, then (i) he must revise his account of coherence accordingly and, more importantly, (ii) such coherence is nof necessary for justification, since intuitively we are justified in (...) accepting such minimally inconsistent belief-sets. If, on the other hand, minimally inconsistent acceptance systems can be coherent, then to prevent pairwise inconsistent statements form readily cohering with such systems, Lehrer must deny that rational acceptance is closed under deduction. (shrink)

In this paper, we analyze an intra-personal game where a decision-maker is summarized by a succession of selves. Selves may (or may not) have conflicting interests, and earlier selves may have imperfect knowledge of the preferences of future selves. At date 1, self-1 chooses a menu, at date 2, the preferences of self-2 realize and self-2 chooses an item from the menu. We show that equilibrium choice is consistent with either a preference for flexibility, a preference for betweenness or a (...) preference for systematic restriction. Overall, the analysis reconciles the decision–theoretic approach of choice over time with the game–theoretic multiple-selves approach. (shrink)

Chemists do not aim at testing preconceptions or theoretical hypotheses only; they first and foremost produce and determine the object of chemical investigation: they learn through making. They never cease to create and stabilize heterogeneous devices, methods, models, and theories in order to act upon the world. Chemical bodies cannot be studied in isolation; their properties constitutively depend on what surrounds and acts upon them. Starting from the specificity of chemical practices, this paper investigates the meaning of consistency, inconsistency, (...) and that of the ceteris paribus clause, in this domain of science. In so doing, it defends the idea that studying what we call ‘a lack of consistency’ should always include the scrutiny of: the way a particular scientific practice is stabilized, and the ontological or pragmatic assumptions about the entities and processes upon which this practice revolves. (shrink)

Cicero often challenged Epicureanism on the grounds of inconsistency. Cicero personifies the charge through his character Torquatus, who defends Epicureanism in De finibus 1–2. Cicero highlights the discrepancies among Torquatus’ beliefs and between them and his behaviour. Torquatus holds that the senses incontestably verify the tenets of Epicureanism, and that logic is superfluous. Yet he is sensitive to the fact that Epicurus’ teachings are not intuitive and require a fair amount of logical argumentation in its defence. Therefore, he defends (...) his school against Cicero's criticisms. But by engaging in a defence of the system, Torquatus has already spoken against his commitment to the obviousness of Epicureanism and his disavowal of logic. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:INCONSISTENCY WITHIN A RECONCILING PROJECT There is nothing I wou'd more willingly lay hold of, than an opportunity of confessing my errors; and shou'd esteem such a return to truth and reason to be more honourable than the most unerring judgment. Hume's words in the first sentence of its Appendix referred to Books I and II of A Treatise of Human Nature. I quote them here with a (...) similarly particular but less glorious reference to Chapter VIII of my Hume's Philosophy of Belief (London, and New York: Routledge and Kegan Paul, and Philosophical Library, 19 61). The errors to be corrected are in the first instance mine. But, if I am now right, they are also and more importantly to be found in the first Inquiry itself. Hume's purpose in Section VIII is to apply to the long disputed question concerning liberty and necessity what he takes to be his discovery that Our idea... of necessity and causation arises entirely from the uniformity observable in the operations of nature, where similar objects are constantly conjoined together, and the mind is determined by custom to infer the one from the appearance of the other. These two circumstances form the whole of that necessity, which we ascribe to matter (Selby-Bigge, EHU 81-82). In urging what is here offered as the new and only correct interpretation of what others want to distinguish as contingent necessity and contingent impossibility, Hume is in their - and my - terms saying that there is no genuine idea of, and no such thing as, contingent necessity and contingent impossibility. There are, that is to say, no true logically contingent propositions asserting certain necessities and impossibilities whether relative or absolute. There are, on the contrary, only logical necessities and logical impossibilities; and these obtain simply as relations of ideas. They do not and cannot either characterize or determine real existence and matter of fact (EHU 25-26). Now certainly, if Hume were right in maintaining either that we cannot coherently assert, or that we never have due warrant for asserting, that any causes necessitate their effects - that they make these, that is, as a matter of fact inevitable and anything else as a matter of fact impossible - then it would become a short and easy task to effect a Compatibilist resolution of the long disputed question. For, on this assumption, nothing more than profound regularities of human behaviour, and sometimes predictabilities, ever have been or ever could be revealed, whether in the everyday experience of the banausic vulgar, or whether by the elevated investigations of the physical and the human sciences. Discoveries of this sort, however, do not and cannot prejudice the familiar realities of human action; which just requires that, in some sense, agents must always be able to do otherwise than they do. This sense - a sense which allows that both the agent who acts freely and the agent who acts under compulsion act - Hume explicates as Locke had done before him in the great chapter 'Of Power' (Essay, II (xxi) 7 ff.). Action necessarily involves a power of acting or not acting, according to the determinations of the will; that is, if we choose to remain at rest, we may; if we choose to move, we also may (EHU 95). 1. Having thus in Part I drawn Compatibilist conclusions from what is in effect his rejection of all contingent necessity and contingent impossibility, Hume proceeds in Part II to apply his findings to the theological special case: to the equally long disputed question of freewill and predestination, that is, rather than of freewill and determinism. After first considering that all reward and punishment must presuppose that the persons to be so treated are the causes of whatever it is for which they are to be rewarded or punished, Hume entertains what ironically he presents as an objection to this theory, with regard to necessity and liberty... It may be said, for instance, that, if voluntary actions be subjected to the same laws of necessity with the operations of matter, there is a continued chain of necessary causes, pre-ordained and pre-determined, reaching from the original cause of all to... (shrink)

The Uniform Determination of Death Act (UDDA) provides that “an individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions or (2) irreversible cessation of all functions of the entire brain, including the brain stem, is dead.” We show that the UDDA contains two conflicting interpretations of the phrase “cessation of functions.” By one interpretation, what matters for the determination of death is the cessation of spontaneous functions only, regardless of their generation by artificial means. By the (...) other, what matters is the cessation of both spontaneous and artificially supported functions. Because each UDDA criterion uses a different interpretation, the law is conceptually inconsistent. A single consistent interpretation would lead to the conclusion that conscious individuals whose respiratory and circulatory functions are artificially supported are actually dead, or that individuals whose brain is entirely and irreversibly destroyed may be alive. We explore solutions to mitigate the inconsistency. (shrink)

Reasoning and change over inconsistent knowledge bases is of utmost relevance in areas like medicine and law. Argumentation may bring the possibility to cope with both problems. Firstly, by constructing an argumentation framework from the inconsistent KB, we can decide whether to accept or reject a certain claim through the interplay among arguments and counterarguments. Secondly, by handling dynamics of arguments of the AF, we might deal with the dynamics of knowledge of the underlying inconsistent KB. Dynamics of arguments has (...) recently attracted attention and although some approaches have been proposed, a full axiomatization within the theory of belief revision was still missing. A revision arises when we want the argumentation semantics to accept an argument. Argument Theory Change encloses the revision operators that modify the AF by analyzing dialectical trees—arguments as nodes and attacks as edges—as the adopted argumentation semantics. In this article, we present a simple approach to ATC based on propositional KBs. This allows to manage change of inconsistent KBs by relying upon classical belief revision, although contrary to it, consistency restoration of the KB is avoided. Subsequently, a set of rationality postulates adapted to argumentation is given, and finally, the proposed model of change is related to the postulates through the corresponding representation theorem. Though we focus on propositional logic, the results can be easily extended to more expressive formalisms such as first-order logic and description logics, to handle evolution of ontologies. (shrink)

We present the inconsistency-adaptive deontic logic DP r , a nonmonotonic logic for dealing with conflicts between normative statements. On the one hand, this logic does not lead to explosion in view of normative conflicts such as O A ∧ O ∼A, O A ∧ P ∼A or even O A ∧ ∼O A. On the other hand, DP r still verifies all intuitively reliable inferences valid in Standard Deontic Logic (SDL). DP r interprets a given premise set ‘as (...) normally as possible’ with respect to SDL. Whereas some SDL-rules are verified unconditionally by DP r , others are verified conditionally. The latter are applicable unless they rely on formulas that turn out to behave inconsistently in view of the premises. This dynamic process is mirrored by the proof theory of DP r. (shrink)

The debate on probabilistic measures of coherence has focused on evaluating sets of consistent propositions. In this paper we draw attention to the largely neglected question of whether such measures concur with intuitions on test cases involving inconsistent propositions and whether they satisfy general adequacy constraints on coherence and inconsistency. While it turns out that, for the vast majority of measures in their original shape, this question must be answered in the negative, we show that it is possible to (...) adapt many of them in order to improve their performance. (shrink)

In this article, I reply to the charge, made in Analysis by Anthony Hatzimoysis, that my criticism of Sartre's Sketch for a Theory of the Emotions is unwarranted. I argued that Sartre offers two lines of reasoning about emotional experience that are in clear conflict with each other. Hatzimoysis counters that we can and should read Sartre's text in a way that avoids attributing inconsistency to Sartre. In response, I argue that Hatzimoysis' suggestion about how one might read the (...) text does not in fact remove the central inconsistency. Pace Hatzimoysis, the inconsistency that I identified remains. (shrink)

Is logical consistency required for a set of beliefs or propositions to be categorically coherent? An affirmative answer is often assumed by mainstream epistemologists, and yet it is unclear why. Cases like the lottery and the preface call into question the assumption that beliefs must be consistent in order to be epistemically rational. And thus it is natural to wonder why all inconsistent sets of propositions are incoherent. On the other hand, Easwaran and Fitelson have shown that particular kinds of (...) inconsistency entail the epistemically ‘irrationality’ of holding certain sets of beliefs. In cases of the latter kind of inconsistency, it seems more reasonable to insist that such sets of beliefs or propositions are categorically incoherent. What the precise relationship is between coherence and consistency depends on the nature of the coherence relation. We shall examine recent attempts to explicate the coherence relation in terms of probabilistic measures of confirmation or agreement to see what they can teach us about the relationship between coherence and consistency. We shall show that some probabilistic measures of coherence allow for inconsistent sets to be categorically coherent, while satisfying plausible epistemic rationality constraints. Other probabilistic measures of coherence impose very strong logical consistency requirements, and some measures are tolerant of most forms of inconsistency. As we try to understand what distinguishes coherence measures in this respect, we will also draw some important lessons about Bayesian confirmation measures and differences in the way that they treat contradictory propositions. (shrink)

In order to reason in a non-trivializing way with contradictions, paraconsistent logics reject some classically valid inferences. As a way to recover some of these inferences, Graham Priest proposed to nonmonotonically strengthen the Logic of Paradox by allowing the selection of “less inconsistent” models via a comparison of their respective inconsistent parts. This move recaptures a good portion of classical logic in that it does not block, e.g., disjunctive syllogism, unless it is applied to contradictory assumptions. In Priest’s approach the (...) inconsistent parts of models are compared in an extensional way by consid- ering their inconsistent objects. This distinguishes his system from the standard format of (inconsistency-)adaptive logics pioneered by Diderik Batens, according to which (atomic) contradictions validated in models form the basis of their comparison. A well-known prob- lem for Priest’s extensional approach is its lack of the Strong Reassurance property, i.e., for specific settings there may be infinitely descending chains of less and less inconsistent models, thus never reaching a minimally inconsistent model. In the following paper, we show that Strong Reassurance holds for the extensional ap- proach under a cardinality-based comparison of the inconsistent parts of models. We develop and study the meta-theory of a class of nonmonotonic inconsistency-tolerant logics based on the extensional and the quantitative comparisons of their respective models, including important model-theoretic properties, such as the Löwenheim-Skolem theorems, as well as principles of nonmonotonic inference. (shrink)

In this book, Peter Vickers argues that inconsistency in science has been massively exaggerated by philosophers. In his view, inconsistent science is neither as rampant nor as damaging as many have supposed. To argue his point, he develops a specific method he calls theory eliminativism and applies it to four case studies from the history of physics and mathematics .The method is original and convincing, and the case studies well researched and compelling. Vickers’ monograph provides a challenge to any (...) philosopher of science who takes inconsistency claims seriously, while also introducing a potentially very useful methodology for analyzing away problematic ‘theory’ discourse in other philosophical debates. Overall then, this is a very creative text and useful for both those directly interested in .. (shrink)

Several writers have argued that the state lacks the moral standing to hold socially deprived offenders responsible for their crimes because the state would be hypocritical in doing so. Yet the state is not disposed to make an unfair exception of itself for committing the same sorts of crimes as socially deprived offenders, so it is unclear that the state is truly hypocritical. Nevertheless, the state is disposed to inconsistently hold its citizens responsible, blaming or punishing socially deprived offenders more (...) often or more harshly than other offenders, even when the crimes are the same. The state’s stable disposition to inconsistently hold offenders responsible undermines its standing to hold offenders responsible for the same reasons that hypocrisy undermines standing; instead of making an unfair exception of itself, the state makes an unfair exception of others. Strikingly, this means that the state lacks the standing to hold anyone responsible for a crime for which it is unfairly disposed to hold citizens responsible inconsistently, not just socially deprived offenders. Thus, it is even more urgent that the state regain its moral standing by working toward a justice system that holds offenders responsible consistently. (shrink)

Do inconsistent laws, which are in the form of inconsistent legal obligations, provide us with good reasons for accepting the possibility of legal gluts, which are true legal statements whose negations are also true? Given the contingencies of the law, it is unlikely that many will deny the possibility of inconsistent legal obligations, but it remains an ongoing debate whether these lead to any legal gluts. In a recent debate, Graham Priest [Priest, G. 2006. In ‘Contradiction’. In First printed by (...) Martinus Nijhoff in 1987. 2nd ed. Oxford: Oxford University Press; Priest, G. 2017. ‘Where Laws Conflict: An Application of the Method of Chunk and Permeate’. In Law and the New Logics, edited by H. Glenn, and L. Smith, 168–180. Cambridge: Cambridge University Press] has argued from inconsistent obligations to legal gluts and JC Beall [Beall, JC 2017. ‘On inconsistent laws and gluts’. In Law and the New Logics, edited by H. Glenn, and L. Smith, 199–207. Cambridge: Cambridge University Press.], while he has acknowledged that there are inconsistent obligations, has argued against Priest’s arguments for legal gluts. In this paper, after reviewing the debate, I adjudicate it and provide reasons for resisting Beall’s arguments again Priest thereby providing a possibility for legal gluts. (shrink)

The first mention of the concept of an inconsistency measure for sets of formulas in first-order logic was given in 1978, but that paper presented only classifications for them. The first actual inconsistency measure with a numerical value was given in 2002 for sets of formulas in propositional logic. Since that time, researchers in logic and AI have developed a substantial theory of inconsistency measures. While this is an interesting topic from the point of view of logic, (...) an important motivation for this work is also that some intelligent systems may encounter inconsistencies in their operation. This research deals primarily with propositional knowledge bases, that is, finite sets of propositional logic formulas. The goal of this paper is to extend the concept of inconsistency measure in a formal way to sets of formulas with the modal operators “necessarily” and “possibly” applied to propositional logic formulas. We use frames for the semantics, but in a way that is different from the way that frames are commonly used in modal logics, in order to facilitate measuring inconsistency. As a set of formulas may have different inconsistency measures for different frames, we define the concept of a standard frame that can be used for all finite sets of formulas in the language. We do this for two languages. The first language, AMPL, contains formulas where a prefix of operators is applied to a propositional logic formula. The second language, CMPL, adds connectives that can be applied to AMPL formulas in a limited way. We show how to extend propositional logic inconsistency measures to such sets of formulas. Finally, we define a new concept, weak inconsistency measure, and show how to compute it. (shrink)