A fascinating recent turn in epistemology focuses on inquiring attitudes like wondering and being curious. Many have argued that these attitudes are governed by norms similar to those that govern our doxastic attitudes. Yet, to date, this work has only considered norms that might *prohibit* having certain inquiring attitudes (``norms of restriction''), while ignoring those that might *require* having them (``norms of expansion''). We aim to address that omission by offering a framework that generates norms of expansion for inquiring attitudes. (...) The framework draws on inferential erotetic logic, which we explain and augment with some theorems. We explore several of the norms that it yields - some sympathetically, others unsympathetically. (shrink)

A lógica, considerada como uma disciplina técnica iniciada por Aristóteles e tipicamente representada pela variedade de cálculos lógicos modernos, constitui um esclarecimento e refinamento de uma convicção e prática presentes no senso comum, ou seja, o fato de que os seres humanos crêem que a verdade pode ser adquirida não apenas por evidência imediata, mas também por meio de argumentos. Como uma primeira aproximação, a lógica pode ser vista como um registro “descritivo” das principais formas de argumento presentes no senso (...) comum, mas o fato de que alguns desses padrões possam realmente permitir a derivação de consequências falsas a partir de premissas verdadeiras impõe a tarefa de tornar explícitos que padrões correspondem a um “raciocínio correto” e quais não. Nesse ponto, a lógica (que contém a apresentação de tais padrões) parece ser dotada de uma característica “normativa”. Isso equivale a dizer se pretende que os cálculos lógicos espelhem adequadamente a noção intuitiva de “consequência lógica” e que nesse sentido eles não podem ser totalmente arbitrários ou convencionais, mas devem satisfazer certos requisitos básicos tais como as condições de correção e (tanto quanto possível) de completude semântica. Em tal forma eles são “julgados” de acordo com os requisitos fundamentais presentes no nível do senso comum e aparecem como “idealizações” das espécies de raciocínio praticadas no senso comum. Por essa razão também vários tipos de cálculos lógicos são inteiramente justificados uma vez que tornam explícitos, de uma forma idealizada, os modos concretos de raciocinar que são impostos pelo particular domínio de referência da disciplina na qual são usados e que são basicamente reconhecidos no senso comum. DOI: 10.5007/1808-1711.2011v15n1p15. (shrink)

Logic, considered as a technical discipline inaugurated by Aristotle and typically represented by the variety of the modern logical calculi, constitutes a clarification and refinement of a conviction and practice present in common sense, that is, the fact that humans believe that truth can be acquired not only by immediate evidence, but also by means of arguments. As a first step logic can be seen as a “descriptive” record of the main forms of the arguments present in common sense, (...) but the fact that some of these patterns can actually allow for the derivation of false consequences from true premises imposes the task of making explicit what patterns correspond to a “correct reasoning” and what not. At this point logic appears endowed with a “normative” characteristic. This amounts to saying that logical calculi are intended to adequately mirror the intuitive notion of “logical consequence” and in this sense they cannot be totally arbitrary or conventional, but must satisfy certain basic requirements such as the conditions of soundness and of semantic completeness. In such a way they are “judged” according to the fundamental requirements present at the level of common sense and appear as “idealizations” of the kinds of reasoning practiced in common sense. For this reason also several kinds of logical calculi are fully justified since they make explicit in an idealized form the concrete ways of reasoning that are imposed by the particular domain of reference of the discipline in which they are used and which are basically recognized in common sense. (shrink)

The present special issue of Disputatio brings together some of the best work recently done in Brazil and Portugal in the tradition of analytic philosophy (broadly conceived). Over the past ten years or so we have witnessed an impressive growth of analytic philosophy in both countries, either in terms of quantity or in terms of quality of the produced philosophy. We hope that this volume capture, at least partly, the dynamics and strength of such development. The range of philosophical problems (...) and topics covered by the contributed essays is vast, cutting across several philosophical disciplines. Indeed, one can find therein issues in philosophical logic, meta-philosophy, ethics, aesthetics, philosophy of science, philosophy of language, philosophy of mathematics and metaphysics. Such variety of subject-matter is also a trait of recent Luso-Brazilian analytic philosophy. (shrink)

By a logical theory I mean a formal system together with its semantics, meta-theory, and rules for translating ordinary language into its notation. Logical theories can be used descriptively (for example, to represent particular arguments or to depict the logical form of certain sentences). Here the logician uses the usual methods of empirical science to assess the correctness of his descriptions. However, the most important applications of logical theories are normative, and here, I argue, the epistemology (...) is that of wide reflective equilibrium. The result is that logic not only assesses our inferential practice but also changes it. I tie my discussion to Thagard's views concerning the relationship between psychology and logic, arguing against him that psychology has and should have only a peripheral role in normative (and most descriptive) applications of logic. (shrink)

SOCREAL 2013 : 3rd International Workshop on Philosophy and Ethics of Social Reality 2013. Hokkaido University, Sapporo, Japan, 25-27 October 2013. Session 2 : Imperatives and Norms.

There is an exegetical quandary when it comes to interpreting Locke's relation to logic.On the one hand, over the last few decades a substantive amount of literature has been dedicated to explaining Locke's crucial role in the development of a new logic in the seventeenth and eighteenth centuries. John Yolton names this new logic the "logic of ideas," while James Buickerood calls it "facultative logic."1 Either way, Locke's Essay is supposedly its "most outspoken specimen" or "culmination."2 Call this reading the (...) 'New Logic interpretation.'On the other hand, from the typical standpoint of a philosopher accustomed to the modern conception of logic, whatever Locke—indeed, whatever most of the... (shrink)

This paper explores an apparent tension between two widely held views about logic: that logic is normative and that there are multiple equally legitimate logics. The tension is this. If logic is normative, it tells us something about how we ought to reason. If, as the pluralist would have it, there are several correct logics, those logics make incompatible recommendations as to how we ought to reason. But then which of these logics should we look to for normative guidance? I (...) argue that inasmuch as pluralism draws its motivation from its ability to defuse logical disputes—that is, disputes between advocates of rival logics—it is unable to provide an answer: pluralism collapses into monism with respect to either the strongest or the weakest admissible logic. (shrink)

The present volume is a sequel to Deontic Logic: Introductory and Systematic Readings : its purpose is to offer a view of some of the main directions of research in contemporary deontic logic. Most of the articles included in Introductory and Systematic Readings represent what may be called the standard modal approach to deontic logic, in which de on tic logic is treated as a branch of modal logic, and the normative concepts of obligation, permission and prohibition are regarded as (...) analogous to the "alethic" modalities necessity, possibility and impossibility. As Simo Knuuttila shows in his contribution to the present volume, this approach goes back to late medieval philosophy. Several 14th century philosophers observed the analogies between deontic and alethic modalities and discussed the deontic interpretations of various laws of modal logic. In contemporary deontic logic the modal approach was revived by G. H. von Wright's classic paper 'Deontic Logic'. Certain analogies between deontic and alethic modalities are obvious and uncontroversial, but the standard approach has often been criticized on the ground that it exaggerates the analogies and tends to ignore those features of normative concepts which distinguish them from other modalities. (shrink)

Western contemporary logic has been used to advance the field of Islamic philosophical theology, which historically utilised Aristotelian-Avicennian logic, on grounds of there being an inherent normativity in logic. This is in spite of the surrounding controversy on the status of logic in the Islamic theological tradition. The normative authority of logic means that it influences the content of what we ought to believe and how we ought to revise those beliefs. This paper seeks to demonstrate that, notwithstanding the (...) incompatible differences between the two systems, the underlying feature of both Western contemporary logic and Aristotelian- Avicennian logic is logical normativity. It then argues that an inherent normativity of logic in the Islamic theological/philosophical tradition is unmotivated. Instead, it proposes to reinstate logic as anti-exceptional within the Islamic theological/philosophical tradition as a viable alternative. (shrink)

Some writers object to logical pluralism on the grounds that logic is normative. The rough idea is that the relation of logical consequence has consequences for what we ought to think and h...

Logical pluralism is the view that there is more than one correct logic. This very general characterization gives rise to a whole family of positions. I argue that not all of them are stable. The main argument in the paper is inspired by considerations known as the “collapse problem”, and it aims at the most popular form of logical pluralism advocated by JC Beall and Greg Restall. I argue that there is a more general argument available that challenges (...) all variants of logical pluralism that meet the following three conditions: that there are at least two correct logical systems characterized in terms of different consequence relations, that there is some sort of rivalry among the correct logics, and that logical consequence is normative. The hypothesis I argue for amounts to conditional claim: If a position satisfies all these conditions, then that position is unstable in the sense that it collapses into competing positions. (shrink)

Logical pluralism is the view that there is more than one correct logic. Most logical pluralists think that logic is normative in the sense that you make a mistake if you accept the premisses of a valid argument but reject its conclusion. Some authors have argued that this combination is self-undermining: Suppose that L1 and L2 are correct logics that coincide except for the argument from Γ to φ, which is valid in L1 but invalid in L2. If (...) you accept all sentences in Γ, then, by normativity, you make a mistake if you reject φ. In order to avoid mistakes, you should accept φ or suspend judgment about φ. Both options are problematic for pluralism. Can pluralists avoid this worry by rejecting the normativity of logic? I argue that they cannot. All else being equal, the argument goes through even if logic is not normative. (shrink)

Advocates of certain paraconsistent logics claim that classical logic provides incorrect norms for reasoning about impossible situations. Some have taken this claim as a sufficient reason to modify classical accounts of consequence. In this paper, I explain and evaluate such an argument based on Graham Priest's fictional story, "Sylvan's Box." I will explain and evaluate an objection to this argument based on a consistent reading of Priest's story offered by Daniel Nolan. However, I will argue that the argument fails for (...) different reasons. It is not the case that classical logic provides incorrect norms for reasoning about impossible situations. I will discuss logical tools, offered by Daniel Nolan, compatible with classical accounts of consequence that allow for non-vacuous reasoning about impossibilities. Finally, I will offer an explanation for seeming tensions between certain classical logic principles and reasoning about impossibilities. (shrink)

Some authors have called into question the normativity of logic, using as an argument that the bridge principles for logical normativity (MacFarlane, In what sense (in any) is logic normative for thought, 2004 )? are just by-products of general epistemic principles for belief. In this paper, I discuss that suggestion from a formal point of view. I show that some important bridge principles can be derived from usual norms for belief. I also describe some possible ways to (...) block this derivation by modifying the epistemic norms or weakening the bridge principles. Finally, I discuss different philosophical interpretations of these results. (shrink)

According to the traditional view in the philosophy of logic facts of logic bear normative authority regarding how one ought to reason. Usually this is to mean that the relation of logical consequence between statements has some special relevance for how one’s beliefs should cohere. However, as I will argue in this article, this is just one way in which logic is normative for reasoning. For one thing, belief is not the only kind of mental state involved in reasoning. (...) Besides adopting and revising beliefs, rational agents pose and resolve questions. For another thing, the consequence relation of classical logic can be conservatively extended such that it includes logical relations between questions as well. Therefore, there is an argument to be made that not only the inference of new beliefs from extant beliefs but also the process of raising additional questions falls under the normative authority of logic. Accordingly, a nuanced account of the normativity of logic presents itself, which convincingly deals with problems such as clutter-avoidance and the paradox of the preface. (shrink)

Presumably, the exponent of logical normativity believes it to be the case that rational agents ought to reason logically. If the converse holds, and the exponent of logical normativity believes either that it is false that rational agents ought to reason logically or that the claim that rational agents ought to reason logically is not truth–functional, then any attempt to formulate sound arguments in support of their position will be either question–begging or self–contradictory. To argue in (...) favour of the normative status of logic involves the assumption that the issue is substantive. I draw a distinction between deontic and axiological normativity as applied to logical theory and demonstrate that because deontic sentences are not truth–functional, logic cannot be normative in the deontic sense. I conclude that the only sense in which logical theory may be thought of as normative is axiologically. (shrink)

Logical pluralism is the view that there is more than one logic. Logical normativism is the view that logic is normative. These positions have often been assumed to go hand-in-hand, but we show that one can be a logical pluralist without being a logical normativist. We begin by arguing directly against logical normativism. Then we reformulate one popular version of pluralism—due to Beall and Restall—to avoid a normativist commitment. We give three non-normativist pluralist views, the (...) most promising of which depends not on logic’s normativity but on epistemic goals. (shrink)

The focus of the article is the notion of normativity in logic and politics and their possible intersections. The twentieth-century divide between the analytical and the continental idea of logic is explored, by noting that they both – with significant differences – can be seen as proposing a ‘bottom-up normativity’, which may have immediate political effects. Logical normativity postulates universality, and a connection between reality and reason able to orient actions universalistically. For a bottom-up conception (as (...) specifically advanced by Deleuze’s logic of sense), the universalistic approach does not descend from above on an elusive reality but is a self-organization of multiple processes occurring in a horizon which is typically affected by political facts and choices. (shrink)

Is logic normative for reasoning? In the wake of work by Gilbert Harman and John MacFarlane, this question has been reduced to: are there any adequate bridge principles which link logical facts to normative constraints on reasoning? Hitherto, defenders of the normativity of logic have exclusively focussed on identifying adequate validity bridge principles: principles linking validity facts—facts of the form 'gamma entails phi'—to normative constraints on reasoning. This paper argues for two claims. First, for the time being at (...) least, Harman’s challenge cannot be surmounted by articulating validity bridge principles. Second, Harman’s challenge can be met by articulating invalidity bridge principles: principles linking invalidity facts of the form 'gamma does not entail phi' to normative constraints on reasoning. In doing so, I provide a novel defence of the normativity of logic. (shrink)

According to received wisdom, Kant takes the laws of logic to be normative laws of thought. This has been challenged by Tolley (2006). In this paper, I defend the received wisdom, but with an important modification: Kant's logical laws are constitutive norms for thought. The laws of logic do tell us what thinking is, not because all thoughts are in conformity with logical laws, but because all thoughts are, by nature, subject to the standard of logic.

Logic is widely held to be a normative discipline. Various claims have been offered in support of this view, but they all revolve around the idea that logic is concerned with how one ought to reason. I argue that most of these claims—while perhaps correct—only entail that logic is normative in a way that many, if not all, intellectual disciplines are normative. I also identify some claims whose correctness would make logic normative in a way that sets it apart from (...) other disciplines. I argue that we have no reason think that these claims are correct. In other words, logic is not a distinctively normative discipline. (shrink)

Logical pluralism is the view that there is more than one correct logic. A key objection to logical pluralism is that it collapses into monism. The core of the Collapse Objection is that only the pluralist’s strongest logic does any genuine normative work; since a logic must do genuine normative work, this means that the pluralist is really a monist, who is committed to her strongest logic being the one true logic. This paper considers a neglected question in (...) the collapse debate: what is it for a logic to do genuine normative work? As well as having wider upshot for the connection between logic and normativity, grappling with this question provides a new response to the Collapse Objection on behalf of the pluralist. I suggest that we should allow logics to generate pro tanto reasons in a way that bears not just on combinations of attitudes but on how an agent’s attitudes are based on one another. This motivates adopting normative principles that allow the pluralist’s weaker logics to earn their normative keep. Rather than being ad hoc, these principles capture a sense in which good reasoning goes beyond the consistency of an agent’s attitudes. Good reasoning is also concerned with how an agent’s attitudes are based on one another. (shrink)

Deontic logic is standardly conceived as the logic of true statements about the existence of obligations and permissions. In his last writings on the subject, G. H. von Wright criticized this view of deontic logic, stressing the rationality of norm imposition as the proper foundation of deontic logic. The present paper is an attempt to advance such an account of deontic logic using the formal apparatus of update semantics and dynamic logic. That is, we first define norm systems and a (...) semantics of norm performatives as transformations of the norm system. Then a static modal logic for norm propositions is defined on that basis. In the course of this exposition we stress the performative nature of (i) free choice permission, (ii) the sealing legal principle and (iii) the social nature of permission. That is, (i) granting a disjunctive permission means granting permission for both disjuncts; (ii) non-prohibition does not entail permission, but the authority can declare that whatever he does not forbid is thereby permitted; and (iii) granting permission to one person means that all others are committed to not prevent the invocation of that permission. (shrink)

Differences among scientific, mathematical, and ethical subject matters motivate a pluralism where distinct domains of subject matter are associated with distinct truth properties and logics. However, it is unclear how such pluralism might accommodate potentially attractive epistemic norms, such as that one ought to believe only what is true, and that one ought to believe what is logically true. In this paper, I show how such pluralism can accommodate such norms by supplementing the account developed in Yu (2017a,b) with epistemic, (...) doxastic, and deontic operators. The upshot is that pluralism is compatible with, even if not committed to, monism about epistemic norms. (shrink)

In this paper, the set-theoretic approach in the logical theory of normative systems is extended using Broome’s definition of the normative code function. The syntax and semantics for first order metanormative language is defined, and metanormative language is applied in the formalization of the basic principles in Broome’s approach and in the construction of a logical typology of normative systems. Special attention is given to the types of normative systems which are not definable in terms of the properties (...) of singular sets of requirements (e.g. the realization equivalence of codes, the social compatibility of codes, and the compatibility of codes issued by different normative sources). Examples are given of the application of the typology in the interpretation of philosophical texts. Von Wright’s hypothesis on the connection of logical properties of normative systems, conceived set-theoretically, with standard deontic logic is proved by introducing the translation function between the metanormative language and the restricted language of standard deontic logic. The translation reveals that von Wright’s hypothesis must be appended. The problems of narrow and wide scope readings of the deontic conditionals and of the meaning of iterated deontic operators are addressed using the distinction between relative and absolute normative codes. The theorem on the existence of a realization equivalent absolute code for any relative code is proved. (shrink)

This anthology contains revised versions of selected papers presented at the the fourth bi-annual international deontic logic conference, DEON’06. There is a substantial introduction (see separate entry), papers from all four invited speakers, David Makinson, Donald Nute, Claudio Pizzi, and Georg Von Wright. After the introduction and lead chapter "Deontic Logic - as I See It" by G.H. von Wright, there are nineteen articles grouped under six headings, "Norms and Truth", "Agency and Time", "Analysis of Normative Conflicts", "Defeasibility and Norm (...) Conflicts", Computer System Applications", and "Combinations of Logics". The collection contains a number of influential articles and a large array of key authors in deontic logic contribute. (shrink)

Physical laws are irresistible. Logical rules are not. That is why logic is said to be normative. Given a system of logic we have a Norma, a standard of correctness. The problem is that we need another Norma to establish when the standard of correctness is to be applied. Subsequently we start by clarifying the senses in which the term ‘Iogic’ and the term ‘normativity’ are being used. Then we explore two different epistemologies for logic to see the (...) sort of defence of the normativity of logic they allow for; if any. The analysis concentrates on the case of classical logic. In particular the issue will be appraised from the perspective put forward by the epistemology based on the methodology of wide reflective equilibrium and the scientific one underlying the view of logic as model. (shrink)

A dialogue-based analysis of informal fallacies does not provide a fully adequate explanation of our intuitions about what is wrong with ad baculum and of when it is admissible and when it is not. The dialogue-based analysis explains well why mild, benign threats can be legitimate in some situations, such as cooperative bargaining and negotiation, but does not satisfactorily account for what is objectionable about more malicious uses of threats to coerce and to intimidate. I propose an alternative deriving partly (...) from virtue theory in ethics and epistemology and partly from Kantian principles of respect for persons as ends-in-themselves. I examine some specific kinds of social relations, e.g., parent-child and partner relationships, and ask what kinds of threats are permissible in these relationships and especially what is wrong with the objectionable threats. My explanation is framed in terms of the good character and contributing virtues of the ideal parent or partner on the one hand, and the bad character and contributing vices of the abusive parent or violent partner on the other. This analysis puts the discussion of theats in the context of virtue theory, of human flourishing, and of the kind of social relations it is best to have. In general, what's wrong with argumentum ad baculum should be explained in terms of the intentions, purposes, and character of threateners, and the differences in intentions and purposes for which threats are made. The characters of those who make the threats will provide the criteria for distinguishing benign and malicious threats. (shrink)

The knowledge norm of assertion is the subject of a lively debate on when someone is in a position to assert something. However, not much has been said about the logic that underlies such debate. In this paper, I propose a formalisation of the knowledge norm in a deontic logic that aims to be explanatory and conceptually sound. Afterwards, I investigate some problems that this formalisation makes visible. This reveals some significant limitations of the underlying logic: it can neither contain (...) Axiom 4 nor Axiom C4. Moreover, sentences of the form p and I have not asserted that p appear to licence a violation of deontic rules. (shrink)

We present a number of modal logics to reason about group norms. As a preliminary step, we discuss the ontological status of the group to which the norms are applied, by adapting the classification made by Christian List of collective attitudes into aggregated, common, and corporate attitudes. Accordingly, we shall introduce modality to capture aggregated, common, and corporate group norms. We investigate then the principles for reasoning about those types of modalities. Finally, we discuss the relationship between group norms and (...) types of collective responsibility. (shrink)

The program put forward in von Wright's last works defines deontic logic as ``a study of conditions which must be satisfied in rational norm-giving activity'' and thus introduces the perspective of logical pragmatics. In this paper a formal explication for von Wright's program is proposed within the framework of set-theoretic approach and extended to a two-sets model which allows for the separate treatment of obligation-norms and permission norms. The three translation functions connecting the language of deontic logic with the (...) language of the extended set-theoretical approach are introduced, and used in proving the correspondence between the deontic theorems, on one side, and the perfection properties of the norm-set and the ``counter-set'', on the other side. In this way the possibility of reinterpretation of standard deontic logic as the theory of perfection properties that ought to be achieved in norm-giving activity has been formally proved. The extended set-theoretic approach is applied to the problem of rationality of principles of completion of normative systems. The paper concludes with a plaidoyer for logical pragmatics turn envisaged in the late phase of Von Wright's work in deontic logic. (shrink)

This paper advocates for the normative role of logic in reasoning. I offer a response, anchored in an externalist perspective, to two fronts of attack against the normativity thesis, namely Harman’s sceptical challenge and the accusation of naturalistic fallacy. On the one hand, I rework dialogical bridge principles and show that such principles satisfy adequacy criteria to deal with Harman’s challenge. On the other hand, I argue that it is possible to derive normative consequences from logical facts. This (...) is because argumentative interactions among agents involve the acceptance of constitutive rules that entail obligations. Hence, since logical rules can be seen as constitutive of the social practice of reasoning, they create prescriptions for reasoning. Bridge principles make those obligations and prohibitions explicit. (shrink)

The biennial DEON conferences are designed to promote interdisciplinary cooperation amongst scholars interested in linking the formal-logical study of normative concepts and normative systems with computer science, artificial intelligence, linguistics, philosophy, organization theory and law. In addition to these general themes, DEON 2016 encouraged a special focus on the topic "Reasons, Argumentation and Justification.".

In general, there is only one fuzzy logic in which the standard interpretation of the strong conjunction is a strict triangular norm, namely, the product logic. We study several equations which are satisfied by some strict t-norms and their dual t-conorms. Adding an involutive negation, these equations allow us to generate countably many logics based on strict t-norms which are different from the product logic.

It’s widely accepted that normativity is not subject to truth values. The underlying reasoning is that truth values can only be predicated of descriptive statements; normative statements are prescriptive, not descriptive; thus truth value predicates cannot be assigned to normative statements. Hence, deonticity lacks logical semantics. This semantic monism has been challenged over the last decades from a series of perspectives that open the way for legal logics with imperative semantics. In the present paper I will go back (...) to Kant and review his understanding of practical judgments, presenting it as supported by a pluralistic semantics. From this perspective a norm of Law is a logical expression that includes as content a generic description of a possible behavior by a generality of juridical agents, and assigns to that content the assertion of its obligatory character, accompanied by a disincentive for non-compliance. From this perspective legal norms can be syntactically formalized and assigned appropriate semantic values in such terms that they can be incorporated into valid inferential schemes. The consequence is that we can put together legal logics that handle both the phenomenal and the deontic dimensions of legality. (shrink)

It is a popular view thatpractical deliberation excludes foreknowledge of one's choice. Wolfgang Spohn and Isaac Levi have argued that not even a purely probabilistic self-predictionis available to thedeliberator, if one takes subjective probabilities to be conceptually linked to betting rates. It makes no sense to have a betting rate for an option, for one's willingness to bet on the option depends on the net gain from the bet, in combination with the option's antecedent utility, rather than on the offered (...) odds. And even apart from this consideration, assigning probabilities to the options among which one is choosing is futile since such probabilities could be of no possible use in choice. The paper subjects these arguments to critical examination and suggests that, appearances notwithstanding, practical deliberation need not crowd outself-prediction. (shrink)

The passionate and staunch defence of logic of the controversial thinker Ibn Ḥazm, Abū Muḥammad ʿAlī b. Aḥmad b. Saʿīd of Córdoba (384-456/994-1064), had lasting consequences in the Islamic world. Indeed, his book Facilitating the Understanding of the Rules of Logic and Introduction Thereto, with Common Expressions and Juristic Examples (Kitāb al-Taqrīb li-ḥadd al-manṭiq wa-l-mudkhal ilayhi bi-l-alfāẓ al-ʿāmmiyya wa-l-amthila al-fiqhiyya), composed in 1025-1029, was well known and discussed during and after his time; and it paved the way for the studies (...) of his compatriots Ibn Bājjah (d. 1138), Ibn Ṭufayl (1185), and Ibn Rushd (1198), who each gave demonstrative reasoning a privileged place within the methods of attaining knowledge. Unfortunately, as too often in the history of science, Ibn Ḥazm’s innovative perspectives and contributions in logic have been overlooked or considered with an attitude of contempt. On the one hand, his work has been seen, at best, as promulgating the benefits of studying Aristotle’s logic, so that his contribution is assessed as more didactical than conceptual. And on the other hand, those who do examine his innovations often consider them to be mistaken. As indicated by Chejne (1984, p. 2) contempt towards the logical work of Ibn Ḥazm was also present in its reception by the Eastern philosophers who accused him of deviating from Aristotelian logic and of dabbling in things beyond his capability. However, a reassessment of his work on logic has since begun, by delving into the ways the thinker of Córdoba studied the links between deontic and modal qualification of propositions. In this context Lameer’s (2013) paper on the logical sources of Ibn Ḥazm is worth mentioning; the author (p. 417, footnote 1) observes that, although, strictly speaking, it was al-Fārābī who first drew the parallelism between deontic and modal concepts, it was Ibn Ḥazm who developed it and worked it out in a more precise manner. A primary aim of this paper is to help fill some of these gaps by stressing the role of the work of Ibn Ḥazm in developing a notion of deontic necessity deeply rooted in legal normativity, and in explicitly discussing the transference between deontic and modal concepts. According to our view; the basic units of Islamic deontic logic are what we might call, indulging in terminological anachronism, heteronomous imperatives. As it turns out, the heteronomy of imperatives within Islamic legal systems contrasts with those of the purely moral realm, which seem to be closer to an autonomous conception of moral law. There it concurs again with Leibniz’s proposal to define obligatory as “what is necessary for a good person to do”. In the present paper, we will focus on the heteronomous imperatives of legal systems rather than on the imperatives of the purely moral realm. In this context, the work of Ibn Ḥazm extends the parallelism between the necessity of events and that of human actions stressed by his predecessors. According to our understanding, Ibn Ḥazm’s parallelism can be rendered explicit formally by means of a conditional (or hypothetical) structure shared by both deontic and modal propositions. Moreover, this structure makes apparent that this parallelism displays an underlying system of “degrees”. Indeed, while in the domain of events, given some conditions, it makes sense to distinguish between an event that is more likely to happen than another. Ibn Ḥazm speaks of near and distant possibility (such as the higher degree of likelihood of rain, given the condensation of clouds in December, and its lower degree, when the condensation occurs in summer); and, in the domain of actions, the Islamic notion of weighting actions determines degrees of virtue (or of legal and moral value). So whereas the degree of virtue of performing a forbidden act as determined by the distribution of sanction and reward is 0, we obtain the same value by pondering the likelihood of an impossible event to take place. Furthermore, as discussed in section II.3.2, the system of values at work in the parallelism can be seen as opening the way to a more direct correspondence. Thus, while in the realm of nature, likelihood of occurrence of an event is dependent upon the conditions specific to the occurrence of that event; while, in the realm of jurisprudence, likelihood of performing an action is dependent upon the distribution of reward and sanction specific to that action (being that, given the choice to perform or not perform a given action, those that will be rewarded are more likely to be performed than those that are not). According to this perspective, the point of the parallelism is that both deontic and modal qualifications measure the degree of an action or event to become actual; that is – indulging once more in anachronism (but this time from the Leibnizian background) – the degree measures how feasible (facile) an action or event may be. This suggests that Ibn Ḥazm’s perspectives already herald the links to probability and possibility explored by Leibniz six centuries later – see for example Leibniz’s (1671, A VI, I, p. 424-26) use of probability in the context of conditional right. Nevertheless, it also shows a crucial difference to the approach developed in the Elementa Jura Naturalis: whereas Leibniz’s studies seek to define what is to be just or virtuous, the logical system of deontic imperatives within Islamic jurisprudence presupposes that what is to be virtuous has already been settled. Determining what is to be virtuous is not achieved by logical reasoning within the system of legal jurisprudence, but by delving into the higher objectives of the Sharīʿa. While developing our point, we will delve into the logical structure of the heteronomous imperatives. This distinguishes our contribution from the existing literature, such as the papers of Chejne (1984), Lameer (2014), and Guerrero (1997, 2010, 2014), which do not provide a logical analysis of the deontic concepts put into work by Ibn Ḥazm. The true antecedent to the present paper is the work of Farid Zidani (2007, 2015), who, so far as we know, was the first to undertake such a task. Some of our own developments and general epistemological thoughts go beyond Ibn Ḥazm’s framework and motivations; mainly those contained in sections II.3.2 and IV. However, according to our view, these reflections suggest that Ibn Ḥazm’s approach has the substance for a broader and deeper exploration of the logic of norms. The paper is structured as follows:I.Ibn Ḥazm’s Logic of Heteronomous Imperatives. After presenting some extracts of the relevant text, we proceed by providing a formal reconstruction of the five forms of deontic modalities. II. A Landmark in the History of the Logical Analysis of Norms. Duties and Modalities. In this section, we study the transferences from deontic to modal necessity and possibility. We briefly compare the deontic system of Islamic Jurisprudence with that of Leibniz.III. Leibniz and Hypothetical Imperatives in Law.IV. Beyond Ibn Ḥazm: Conclusions and the Work Ahead. We will conclude the paper by discussing briefly some conceptual points that distinguish the logic of heteronomous imperatives from contemporary deontic logic. Our final words will discuss deontic-modal parallelism in the context of Ibn Ḥazm’s rejection of reasoning by conjecture and what we call “the internalization of nature.”. (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)