This book argues that the meaning of negation, perhaps the most important logical constant, cannot be defined within the framework of the most comprehensive theory of proof-theoretic semantics, as formulated in the influential work of Michael Dummett and Dag Prawitz. Nils Kürbis examines three approaches that have attempted to solve the problem - defining negation in terms of metaphysical incompatibility; treating negation as an undefinable primitive; and defining negation in terms of a speech act of denial - and concludes that (...) they cannot adequately do so. He argues that whereas proof-theoretic semantics usually only appeals to a notion of truth, it also needs to appeal to a notion of falsity, and proposes a system of natural deduction in which both are incorporated. Offering new perspectives on negation, denial and falsity, his book will be important for readers working on logic, metaphysics and the philosophy of language. (shrink)

_Material Falsity and Error in Descartes’s Meditations _approaches Descartes’s Meditations as an intellectual journey, wherein Descartes’s views develop and change as he makes new discoveries about self, God and matter. The first book to focus closely on Descartes’s notion of material falsity, it shows how Descartes’s account of material falsity – and correspondingly his account of crucial notions such as truth, falsehood and error – evolves according to the epistemic advances in the Meditations. It also offers important (...) new insights on the crucial role of Descartes’s Third Meditation discussion of material falsity in advancing many subsequent arguments in the Meditations. This book is essential reading for those working on Descartes and early modern philosophy. It presents an independent reading on issues of perennial interest, such as Descartes’s views on error, truth and falsehood. It also makes important contributions to topics that have been the focus of much recent scholarship, such as Descartes’s ethics and his theodicy. Those working on the interface between medieval and modern philosophy will find the discussions on Descartes’s debt to predecessors like Suárez and Augustine invaluable. (shrink)

_Material Falsity and Error in Descartes’s Meditations _approaches Descartes’s Meditations as an intellectual journey, wherein Descartes’s views develop and change as he makes new discoveries about self, God and matter. The first book to focus closely on Descartes’s notion of material falsity, it shows how Descartes’s account of material falsity – and correspondingly his account of crucial notions such as truth, falsehood and error – evolves according to the epistemic advances in the Meditations. It also offers important (...) new insights on the crucial role of Descartes’s Third Meditation discussion of material falsity in advancing many subsequent arguments in the Meditations. This book is essential reading for those working on Descartes and early modern philosophy. It presents an independent reading on issues of perennial interest, such as Descartes’s views on error, truth and falsehood. It also makes important contributions to topics that have been the focus of much recent scholarship, such as Descartes’s ethics and his theodicy. Those working on the interface between medieval and modern philosophy will find the discussions on Descartes’s debt to predecessors like Suárez and Augustine invaluable. (shrink)

This paper synthesizes convergent lines of evidence to evaluate the hypothesis that objective falsity is essential to lying. Objective accounts of lying affirm this hypothesis; subjective accounts deny it. Evidence from history, logic, social observation, popular culture, lexicography, developmental psychology, inference, spontaneous description, and behavioral experimentation strongly supports the hypothesis. Studies show that the only apparent evidence against the hypothesis is due to task substitution, i.e. ethical concerns or perspective-taking interfering with performance on categorization tasks. I conclude that, overall, (...) existing evidence decisively favors objective accounts. (shrink)

According to the principle of bivalence, truth and falsity are jointly exhaustive and mutually exclusive options for a statement. It is either true or false, and not both, even in a borderline case. That highly controversial claim is central to the epistemic theory of vagueness, which holds that borderline cases are distinguished by a special kind of obstacle to knowing the truth-value of the statement. But this paper is not a defence of the epistemic theory. If bivalence holds, it (...) presumably does so as a consequence of what truth and falsity separately are. One may therefore expect bivalence to be derivable from a combination of some principles characterizing truth and other principles characterizing falsity. Indeed, such derivations are easily found. Their form will of course depend on the initial characterizations of truth and falsity, and not all such characterizations will permit bivalence to be derived. In this paper we focus on the relation between its derivability and some principles about truth and falsity. We will use borderline cases for vague expressions as primary examples of an urgent.. (shrink)

Arnauld's criticisms as "a model of confusion confounded.” In a review of Wilson's book, R. McRae refers to "the difficult and not too coherent subject of material falsity. '' J. Cottingham describes the Descartes-Arnauld debate on the material falsity of adventitious ideas as "an involved and rather inconclusive exchange " and claims that the example of the material falsity of such ideas espoused by Descartes in Meditation III is "needlessly complicated. " A. Kenny, in turn, notes that (...) several things are "confusing in Descartes' account of false ideas. " Later reference is made to the fact that "Descartes appears confused. [...] and that "Descartes, it seems, cannot give a consistent answer. '' As will become clear, I take issue with each of these assessments. When Descartes' position on material falsity is understood in the light of late Scholastic sources, especially Suarez, whence it draws its strength and inspiration, the alleged confusion and incoherency vanishes. .. (shrink)

A theory T is trustworthy iff, whenever a theory U is interpretable in T, then it is faithfully interpretable. In this paper we give a characterization of trustworthiness. We provide a simple proof of Friedman’s Theorem that finitely axiomatized, sequential, consistent theories are trustworthy. We provide an example of a theory whose schematic predicate logic is complete Π20.

In §1 I explain that my rejection of possible states of affairs as a basis for an account of falsity is not part of a general rejection of modal notions but is a rejection of possible and impossible entities of any sort. I then show that my account of senses and of propositions is indeed a modal account. In §2 I examine some of Wittgenstein’s ideas about falsity, as presented by Luiz Carlos, in relation to my account of (...) falsity and negation. In §3 I discuss the modal aspects of identification for propositions. (shrink)

We give a procedure to obtain falsity conditions for IF-sentences, using Skolemization. The expressive power of an IF-sentence can then be strongly captured by a pair of Σ11-sentences. A result from [Burgess 2003] shows that, conversely, any pair of incompatible Σ11-sentences corresponds with an IF-sentence.In the second part, we reflect on the influence of the order of the steps (inside-out versus outside-in) in the Skolemization procedures for IF-logic. We also reflect on the nature of game theoretical negation.

We give a procedure to obtain falsity conditions for IF-sentences, using Skolemization. The expressive power of an IF-sentence can then be strongly captured by a pair of Σ11-sentences. A result from [Burgess 2003] shows that, conversely, any pair of incompatible Σ11-sentences corresponds with an IF-sentence.In the second part, we reflect on the influence of the order of the steps (inside-out versus outside-in) in the Skolemization procedures for IF-logic. We also reflect on the nature of game theoretical negation.

In Metaphysics Delta 29 Aristotle distinguishes three classes of falsity and three corresponding senses of the ‘false’. The paper examines Aristotle’s arguments from a close-reading perspective, and analyses the meaning of false ‘as a thing’ , the significance of Aristotle’s dispute with Antisthenes on the subject of contradiction and verbal falsehood, and Aristotle’s conception of the false person. By paying attention to the precise order of Aristotle’s presentation, the paper raises the question about the manner in which the three (...) classes of falsity are related to one another and provides a tentative answer that could explain why the ‘false’ is included in the philosophical dictionary of the Metaphysics. On the proposed interpretation, Aristotle assumes that a fundamental difference operates in all cases of falsity , and that this difference is the outcome of the ontological determinacy of substance. Keywords: Aristotle; Metaphysics; falsity; factual falsity; propositional falsity; ethical falsity; Antisthenes; contradiction; substance; ontology; logic. (shrink)

It is widely held that there are important differences between indicative conditionals (e.g. “If the authors are linguists, they have written a linguistics paper”) and subjunctive conditionals (e.g. “If the authors had been linguists, they would have written a linguistics paper”). A central difference is that indicatives and subjunctives convey different stances towards the truth of their antecedents. Indicatives (often) convey neutrality: for example, about whether the authors in question are linguists. Subjunctives (often) convey the falsity of the antecedent: (...) for example, that the authors in question are not linguists. This paper tests prominent accounts of how these different stances are conveyed: whether by presupposition or conversational implicature. Experiment 1 tests the presupposition account by investigating whether the stances project – remain constant – when embedded under operators like negations, possibility modals, and interrogatives, a key characteristic of presuppositions. Experiment 2 tests the conversational-implicature account by investigating whether the stances can be cancelled without producing a contradiction, a key characteristic of implicatures. The results provide evidence that both stances – neutrality about the antecedent in indicatives and the falsity of the antecedent in subjunctives – are conveyed by conversational implicatures. (shrink)

Descartes claims in the Third Meditation that ideas of sense might be materially false. While an accurate interpretation of this claim has the potential of providing some valuable insights into Descartes's theory of ideas in general and his understanding of the epistemic status of sensations in particular, the explanation Descartes provides of the material falsity of ideas is itself obscure and misleading, making accurate interpretation difficult. In this paper an interpretation of material falsity is offered which identifies the (...) fault of materially false ideas in the logical incoherence of their objective content. The implications of this interpretation are also discussed. (shrink)

Although there is a massive amount of work on truth, there is very little work on falsity. Most philosophers probably think this is appropriate; after all, once we have a solid understanding of truth, falsity should not prove to be much of a challenge. However, there are several interesting and difficult issues associated with understanding falsity. After considering two prominent definitions of falsity and presenting objections to each one, I propose a definition that avoids their problems.

Keith DeRose has argued that context shifting experiments should be designed in a specific way in order to accommodate what he calls a ‘truth/falsity asymmetry’. I explain and critique DeRose's reasons for proposing this modification to contextualist methodology, drawing on recent experimental studies of DeRose's bank cases as well as experimental findings about the verification of affirmative and negative statements. While DeRose's arguments for his particular modification to contextualist methodology fail, the lesson of his proposal is that there is (...) good reason to pay close attention to several subtle aspects of the design of context shifting experiments. (shrink)

In an article in a previous issue of this journal, I argue against the falsity criterion in the definition of delusion by presenting cases of delusions that are not false. I thank José Eduardo Porcher for his thought-provoking reply to my article. Although Porcher agrees that the falsity criterion is incorrect, he argues that my method of showing this is unsatisfactory on the grounds that it relies on a pre-defined conception of delusion.

Negation, denial and falsity lie at the heart of debates about logic. We set out the classical account of the relationship between negation and denial, owing to Frege and Geach. We then challenge this on the basis that it does not permit an adequate account of falsity. A dialetheic alternative is minuted and criticised before a novel rejectivist account is proposed according to which falsity is the aim of the speech‐act of denial, whilst negation embeds deniability into (...) assertoric contexts. (shrink)

Does lying require objective falsity? Given that consistency with ordinary language is a desideratum of a philosophical definition of lying, empirical evidence plays an important role. A literature review reveals that studies employing a simple question-and-response format, such as “Did the speaker lie? [Yes/No]”, favour the subjective view of lying, according to which objective falsity is not required. However, it has recently been claimed that the rate of lie attributions found in those studies is artificially inflated due to (...) perspective taking; and that if measures are applied to avoid this problem, the results actually support the objective view of lying. This paper presents three experiments that challenge this claim by showing that the findings used to support the objective view have been misinterpreted. It is thus concluded that the folk concept of lying does not require objective falsity, which is consistent with the dominant view in the philosophical literature. (shrink)

Why do utterances of counterfactual conditionals typically, but not universally, convey the message that their antecedents are false? I demonstrate that two common theoretical commitments–commitment to the existence of scalar implicature and of informative presupposition—can be supplemented with an independently motivated theory of the presuppositions of competing conditional alternatives to jointly predict this information when and only when it appears. The view works best if indicative and counterfactual conditionals have a closely related semantics, so I conclude by undermining two familiar (...) arguments for a nonunified semantics of indicative and counterfactual conditionals. (shrink)

From certain sorts of premise, individuals reliably infer invalid conclusions. Two Experiments investigated a possible cause for these illusory inference: Reasoners fail to think about what is false. In Experiment 1, 24 undergraduates drew illusory and control inferences from premises based on exclusive disjunctions (“or else”). In one block, participants were instructed to falsify the premises of each illusory and control inference before making the inference. In the other block, participants did not receive these instructions. There were more correct answers (...) for illusory disjunctions whose premises had been falsified than there were for illusory disjunctions that had not been falsified. A second Experiment introduced illusory inferences in a real world context that accentuated falsification of premises. Accuracy also improved. Knowledge of how to falsify premises and to consider their implications for true premises transferred to a new problem introduced at the end of the Experiment without the falsification instruction. The participants' ratings of the difficulty of the inferences showed that they did not err simply because illusory inferences are perceived to be more difficult than control problems. The model theory predicts these results because it postulates that the limitations of working memory preclude the representation of false information. (shrink)

This book aims to overturn the common view of materially false ideas , which is that Descartes’s discussion in Meditation Three generates confusion about his views on truth and falsehood and is irrelevant to the rest of the argument in the Meditations.After introducing MFIs and then criticizing previous interpretations, Wee provides her own account in chapter three. Since a proper understanding of why MFIs fail in their representational function allows Wee to revisit their role in the Meditations, this chapter occupies (...) a central place in the book. She attributes to Descartes two theories of representation, the “Accurate Causal Account” and the “Alternative Account” . According to ACP, “an idea represents truly only if the idea comes from the cause from which it purports to come, and the idea accurately represents that cause” . According to AA, an idea is true “if it represents a thing with objective being ” .Since Descartes, in Meditation Three, is “unable to determine the causes of his . . . ‘adventitious’ ideas, far less to determine whether his ideas accurately represent their causes” , the claim that MFIs “represent no-things as things” is to be explained in light of AA as follows: “Under AA, all ideas purport to. (shrink)

Both Socrates and Mozi are said in Plato’s dialogues and in the Mozi respectively to have claimed that they are living a sort of life following superhuman “intention”: Socrates according to the Delphic oracle, and Mozi the intention of heaven. Some modern philosophers show discomfort with their “superstitious” attitudes, taking the claims literally as a kind of groundless devotion, while others conjecture “sensible” purposes to understand the mystic elements as providing moral lessons. This paper, by responding to these modern revisions (...) of their doctrines, aims at highlighting the necessity of their (re-)introductions of superhuman perspectives to their inquiries. Through examining the similarities in Plato’s and Mohists’ demonstrations, the suggestion made will be that despite countless incommensurable features, heaven’s intention for Mohists offers a fundamental philosophical basis which enables them to develop arguments by means of sharp dichotomies, what is right or wrong, in the same way that Socrates in the Apology and in the Hippias Minor does for the development of Plato’s constructive endeavour beyond his Socratic a/euporetic legacy. Not only are their practices dependent on the presupposition of the existence of a perspective beyond humans, but also the reality of that perspective is established though their own investigative practices. (shrink)

This paper aims to establish three major theses: (1) Not only declarative sentences, but also interrogatives and imperatives, may be classified as true or as false. (2) Declarative, imperative, and interrogative utterances may also be classified as honest or as dishonest. (3) Whether an utterance is honest or dishonest is logically independent of whether it is true or is false. The establishment of the above theses follows upon the adoption of a principle for identifying what is meant by any sentence, (...) declarative, interrogative, or imperative. The analysis aims to show that meaning is to be attributed to the uttered or written sentence-token, rather to the thereby exhibited sentence-type. Further, the meaning of the sentential token is to be identified with a purpose of the speaker, that the speaker would reveal to the addressee by uttering the sentence. The to be revealed purpose is analysed into two components: an ultimate concern (that the addressee stand in such and such a relation--e.g., of believing, or informing the speaker about, or making it true that) and an ultimate topic of concern (the state of affairs, i.e., proposition, relative to which the speaker would have the addressee stand in the specified relation). Sentential utterances "signify" different purposes by "expressing" different ultimate concerns and "indicating" different ultimate topics of concern. Variations in expressed concern are correlated with variations in sentential form, such as declarative, interrogative and imperative. Variations in indicated topic of concern are correlated with variations in the subject and predicate of the uttered sentence. Thus, for example, utterances of "Johnny will jump in the lake," "Will Johnny jump in the lake?" and "Johnny, go jump in the lake!" all indicate one and the same ultimate topic of concern but express different ultimate concerns with this topic. A sentential utterance is true or false according as its indicated topic of concern is true or false. Hence, declaratives, interrogatives and imperatives may all be classified as true or as false. But honesty or dishonesty is a function (explained in the paper) of the expressed concern, rather than of the topic of concern. Hence, although utterances of all sentential forms are honest or dishonest, their honesty or dishonesty is logically independent of their truth or falsity. (shrink)

In this paper, we study logical systems which represent entailment relations of two kinds. We extend the approach of finding ‘exactly true’ and ‘non-falsity’ versions of four-valued logics that emerged in series of recent works [Pietz & Rivieccio (2013). Nothing but the truth. Journal of Philosophical Logic, 42(1), 125–135; Shramko (2019). Dual-Belnap logic and anything but falsehood. Journal of Logics and their Applications, 6, 413–433; Shramko et al. (2017). First-degree entailment and its relatives. Studia Logica, 105(6), 1291–1317] to the (...) case of infectious logics, namely to the case of Deutsch's logic Sfde introduced in Deutsch [Relevant analytic entailment. The Relevance Logic Newsletter, 2(1), 26–44; The completeness of S. Studia Logica, 38(2), 137–147]. The particular systems obtained in this way are Setl and Snfl. We present them in the form of sequent calculi and prove corresponding soundness and completeness theorems. We illuminate the connection between Setl, Snfl and two well-known systems, strong Kleene three-valued logic K3 and Priest's Logic of Paradox LP. This connection allows us to investigate the characterisation of the entailment relations associated with Setl and Snfl as well as to introduce the notion of ‘infectious analogue’ of a certain logic. We also study implicative extensions of Setl and Snfl and prove soundness and completeness theorems for them as well. (shrink)

In one of their papers, Michael De and Hitoshi Omori observed that the notion of classical negation is not uniquely determined in the context of so-called Belnap-Dunn logic, and in fact there are 16 unary operations that qualify to be called classical negation. These varieties are due to different falsity conditions one may assume for classical negation. The aim of this paper is to observe that there is an interesting way to make sense of classical negation independent of (...) class='Hi'>falsity conditions. We discuss two equivalent semantics, and offer a Hilbert-style system that is sound and complete with respect to the semantics. (shrink)

This paper argues that the obvious validity of certain inferences involving indirect speech reports as premises and truth or falsity ascriptions as conclusions is incompatible with Davidson's so-called "paratactic" analysis of the logical form of indirect discourse. Besides disqualifying that analysis, this problem is also claimed to indicate that the analysis is doubly in tension with Davidson's metasemantic views. Specifically, it can be reconciled neither with one of Davidson's key assumptions regarding the adequacy of the kind of semantic theory (...) he recommends nor with one of his key assumptions regarding the inadequacy of a kind of semantic theory he rejects. (shrink)

In Adelaster (2016), A. G. Conte proposes a distinction between de dicto and de re attributions of truth and falsity, which he illustrates mostly with documents of legal standing, but also with an artificial object (a false tooth). The present aim is to propose an analogous distinction between monadic (one-place) and polyadic uses of “true” and “false”, and to sketch some features of its logical functioning with closer attention to the monadic pole than is usual. One proposal is that, (...) in these uses, “true” and “false” do not function as opposites under negation. (shrink)

Our linguistic communication is, in part, the exchange of truths. It is an empirical fact that in daily conversation we aim at truths, not falsehoods. This fact may lead us to assume that ordinary, assertion-based communication is the only possible communicative system for truth-apt information exchange, or at least has priority over any alternatives. This assumption is underwritten in three traditional doctrines: that assertion is a basic notion, in terms of which we define denial; that to predicate truth of a (...) sentence is to assert the content it expresses; and that one should, in the context of radical interpretation, try to maximize the truth of what foreigners believe or utter. However, I challenge this assumption via a thought experiment: imagine a language game in which everyone aims to exchange only falsehoods. I argue that information exchange is possible in this game, and so truth-guided communication and falsity-guided communication are conceptually on a par. As a consequence, we should reject the three doctrines, based as they are on the conceptual priority of assertion-based communication. (shrink)

Our linguistic communication is, in part, the exchange of truths. It is an empirical fact that in daily conversation we aim at truths, not falsehoods. This fact may lead us to assume that ordinary, assertion-based communication is the only possible communicative system for truth-apt information exchange, or at least has priority over any alternatives. This assumption is underwritten in three traditional doctrines: that assertion is a basic notion, in terms of which we define denial; that to predicate truth of a (...) sentence is to assert the content it expresses; and that one should, in the context of radical interpretation, try to maximize the truth of what foreigners believe or utter. However, I challenge this assumption via a thought experiment: imagine a language game in which everyone aims to exchange only falsehoods. I argue that information exchange is possible in this game, and so truth-guided communication and falsity-guided communication are conceptually on a par. As a consequence, we should reject the three doctrines, based as they are on the conceptual priority of assertion-based communication. (shrink)

Here I develop an interpretation of Descartes' theory of ideas which differs from the standard reading in that it incorporates a distinction between what an idea appears to represent and what it represents. I argue that this interpretation not only finds support in the texts but also is required to explain a large number of assertions in Descartes which would otherwise appear irremediably obscure or problematic. For example, in my interpretation it is not puzzling that Descartes responds to Arnauld's difficulty (...) concerning the notion of material falsity by drawing a distinction between that to which an idea conforms (that of which the idea truly is) and that to which it refers. Furthermore, my interpretation also explains how Descartes can intelligibly reject the view that saying that something is clear and distinct is equivalent to saying that it is obvious. Finally, I argue that my interpretation allows Descartes' view that we have some sort of internal access to the objects actually represented by an idea. (shrink)

As is made clear by the exergue by Carlo Ginzburg at the beginning of the introduction to the volume, the topic of fakes, forgeries, deceptions, and hoaxes in early modern science touches upon several crucial issues for historians of science, such as the possibilities of disentangling the true from the false in writing history, and to assess criteria of demarcations of truth and falsity in knowledge. Moreover, dealing with fakes also means going beyond rigid disciplinary boundaries. Indeed, the editors (...) Marco Beretta and Maria Conforti underline that the inspirational sources for this book—which has its origins from the Second Watson Seminar in the History of Material and Visual Science held at the Museo Galileo in Florence in June 2013—range from Orson Welles to Trevor Roper’s famous The Hermit of Peking. Consequently, starting from the “rather naïve question” of why, since fakes, forgeries, and deception techniques proliferate in early modern sciences and culture, we still have v .. (shrink)