The aim of this paper is to propose a formal approach to reasoning about desires, understood as logical propositions which we would be pleased to make true, also acknowledging the fact that desire is a matter of degree. It is first shown that, at the static level, desires should satisfy certain principles that differ from those to which beliefs obey. In this sense, from a static perspective, the logic of desires is different from the logic of beliefs. While the accumulation (...) of beliefs tend to reduce the remaining possible worlds they point at, the accumulation of desires tends to increase the set of states of affairs tentatively considered as satisfactory. Indeed beliefs are expected to be closed under conjunctions, while, in the positive view of desires developed here, one can argue that endorsing \ as a desire means to desire \ and to desire \. However, desiring \ and \ at the same time is not usually regarded as rational, since it does not make much sense to desire one thing and its contrary at the same time. Thus when a new desire is added to the set of desires of an agent, a revision process may be necessary. Just as belief revision relies on an epistemic entrenchment relation, desire revision is based on a hedonic entrenchment relation satisfying other properties, due to the different natures of belief and desire. While epistemic entrenchment relations are known to be qualitative necessity relations, hedonic relations obeying a set of reasonable postulates correspond to another set-function in possibility theory, called guaranteed possibility, that drive well-behaved desire revision operations. Then the general framework of possibilistic logic provides a syntactic setting for encoding desire change. The paper also insists that desires should be carefully distinguished from goals. (shrink)

The paper first introduces a cube of opposition that associates the traditional square of opposition with the dual square obtained by Piaget’s reciprocation. It is then pointed out that Blanché’s extension of the square-of-opposition structure into an conceptual hexagonal structure always relies on an abstract tripartition. Considering quadripartitions leads to organize the 16 binary connectives into a regular tetrahedron. Lastly, the cube of opposition, once interpreted in modal terms, is shown to account for a recent generalization of formal concept analysis, (...) where noticeable hexagons are also laid bare. This generalization of formal concept analysis is motivated by a parallel with bipolar possibility theory. The latter, albeit graded, is indeed based on four graded set functions that can be organized in a similar structure. (shrink)

This paper presents and discusses several methods for reasoning from inconsistent knowledge bases. A so-called argued consequence relation, taking into account the existence of consistent arguments in favour of a conclusion and the absence of consistent arguments in favour of its contrary, is particularly investigated. Flat knowledge bases, i.e., without any priority between their elements, are studied under different inconsistency-tolerant consequence relations, namely the so-called argumentative, free, universal, existential, cardinality-based, and paraconsistent consequence relations. The syntax-sensitivity of these consequence relations is (...) studied. A companion paper is devoted to the case where priorities exist between the pieces of information in the knowledge base. (shrink)

This paper first investigates logical characterizations of different structures of opposition that extend the square of opposition in a way or in another. Blanché’s hexagon of opposition is based on three disjoint sets. There are at least two meaningful cubes of opposition, proposed respectively by two of the authors and by Moretti, and pioneered by philosophers such as J. N. Keynes, W. E. Johnson, for the former, and H. Reichenbach for the latter. These cubes exhibit four and six squares of (...) opposition respectively. We clarify the differences between these two cubes, and discuss their gradual extensions, as well as the one of the hexagon when vertices are no longer two-valued. The second part of the paper is dedicated to the use of these structures of opposition for discussing the comparison of two items. Comparing two items usually involves a set of relevant attributes whose values are compared, and may be expressed in terms of different modalities such as identity, similarity, difference, opposition, analogy. Recently, J.-Y. Béziau has proposed an “analogical hexagon” that organizes the relations linking these modalities. Elementary comparisons may be a matter of degree, attributes may not have the same importance. The paper studies in which ways the structure of the hexagon may be preserved in such gradual extensions. As another illustration of the graded hexagon, we start with the hexagon of equality and inequality due to R. Blanché and extend it with fuzzy equality and fuzzy inequality. Besides, the cube induced by a tetra-partition can account for the comparison of two items in terms of preference, reversed preference, indifference and non-comparability even if these notions are a matter of degree. The other cube, which organizes the relations between the different weighted qualitative aggregation modes, is more relevant for the attribute-based comparison of items in terms of similarity. (shrink)

1. There are two distinct lines of research that aim at modelling belief and knowledge: modal logic and uncertainty theories. Modal logic extends classical logic by introducing knowledge or belief...

The starting point of this work is the gap between two distinct traditions in information engineering: knowledge representation and data - driven modelling. The first tradition emphasizes logic as a tool for representing beliefs held by an agent. The second tradition claims that the main source of knowledge is made of observed data, and generally does not use logic as a modelling tool. However, the emergence of fuzzy logic has blurred the boundaries between these two traditions by putting forward fuzzy (...) rules as a Janus-faced tool that may represent knowledge, as well as approximate non-linear functions representing data. This paper lays bare logical foundations of data - driven reasoning whereby a set of formulas is understood as a set of observed facts rather than a set of beliefs. Several representation frameworks are considered from this point of view: classical logic, possibility theory, belief functions, epistemic logic, fuzzy rule-based systems. Mamdani's fuzzy rules are recovered as belonging to the data - driven view. In possibility theory a third set-function, different from possibility and necessity plays a key role in the data - driven view, and corresponds to a particular modality in epistemic logic. A bi-modal logic system is presented which handles both beliefs and observations, and for which a completeness theorem is given. Lastly, our results may shed new light in deontic logic and allow for a distinction between explicit and implicit permission that standard deontic modal logics do not often emphasize. (shrink)

This paper investigates simple syntactic methods for revising prioritized belief bases, that are semantically meaningful in the frameworks of possibility theory and of Spohn''s ordinal conditional functions. Here, revising prioritized belief bases amounts to conditioning a distribution function on interpretations. The input information leading to the revision of a knowledge base can be sure or uncertain. Different types of scales for priorities are allowed: finite vs. infinite, numerical vs. ordinal. Syntactic revision is envisaged here as a process which transforms a (...) prioritized belief bases into a new prioritized belief base, and thus allows a subsequent iteration. (shrink)

The aim of this work is to revisit the proposal made by Dag Westerståhl a decade ago when he provided a modern reading of the traditional square of opposition and of related structures. We propose a formalization of this modern view and contrast it with the classical one. We discuss what may be a modern hexagon of opposition and a modern cube, and show their interest in particular for relating quantitative expressions.

Possibilistic logic and modal logic are knowledge representation frameworks sharing some common features, such as the duality between possibility and necessity, and the decomposability of necessity for conjunctions, as well as some obvious differences since possibility theory is graded. At the semantic level, possibilistic logic relies on possibility distributions and modal logic on accessibility relations. In the last 30 years, there have been a series of attempts for bridging the two frameworks in one way or another. In this paper, we (...) compare the relational semantics of epistemic logics with simpler possibilistic semantics of a fragment of such logics that only uses modal formulas of depth 1. This minimal epistemic logic handles both all-or-nothing beliefs and explicitly ignored facts. We also contrast epistemic logic with the S5-based rough set logic. Finally, this paper presents extensions of generalized possibilistic logic with objective and non-nested multimodal formulas, in the style of modal logics KD45 and S5. (shrink)

The problem of merging multiple sources information is central in many information processing areas such as databases integrating problems, multiple criteria decision making, expert opinion pooling, etc. Recently, several approaches have been proposed to merge classical propositional bases, or sets of (non-prioritized) goals. These approaches are in general semantically defined. Like in belief revision, they use priorities, generally based on Dalal's distance, for merging the classical bases and return a new classical base as a result. An immediate consequence of the (...) generation of a classical base is the impossibility of iterating the fusion process in a coherent way w.r.t. priorities since the underlying ordering is lost. This paper presents a general approach for fusing prioritized bases, both semantically and syntactically, when priorities are represented in the possibilistic logic framework. Different classes of merging operators are considered including conjunctive, disjunctive, reinforcement and adaptive operators. We show that the approaches which have been recently proposed for merging classical propositional bases can be embedded in this setting. The result is then a prioritized base, and hence the process can be coherently iterated. Moreover, we also provide a syntactic counterpart for the fusion of classical bases. (shrink)

The paper presents a ‘multiple agent’ logic where formulas are pairs of the form, made of a proposition and a subset of agents. The formula is intended to mean ‘ all agents in believe that is true’. The formal similarity of such formulas with those of possibilistic logic, where propositions are associated with certainty levels, is emphasised. However, the subsets of agents are organised in a Boolean lattice, while certainty levels belong to a totally ordered scale. The semantics of a (...) set of ‘multiple agent’ logic formulas is expressed by a mapping which associates a subset of agents with each interpretation. Soundness and completeness results are established. Then a joint extension of the multiple agent logic and possibilistic logic is outlined. In this extended logic, propositions are then associated with both sets of agents and certainty levels. A formula then expresses that ‘all agents in set believe that is true at least at some level’. The semantics is then given in terms of fuzzy sets of agents that find an interpretation more or less possible. A specific feature of possibilistic logic is that the inconsistency of a knowledge base is a matter of degree. The proposed setting enables us to distinguish between the global consistency of a set of agents and their individual consistency. In particular, given a set of multiple agent possibilistic formulas, one can compute the subset of agents that are individually consistent to some degree. (shrink)

Early childhood is characterized by many cognitive developmentalists as a period of considerable change with respect to representational format. Dienes & Perner present a potentially viable theory for the stages involved in the increasingly explicit representation of knowledge. However, in our view they fail to map their multi-level system of explicitness onto cognitive developmental changes that occur in the first years of life. Specifically, we question the theory's heuristic value when applied to the development of early mind reading and categorization. (...) We conclude that the authors fail to present evidence that dispels the view that knowledge change in these areas is dichotomous. (shrink)

Tomasello et al. have presented a position that is grounded in a conservative perspective of cultural learning, as well as in a rich interpretation of recent findings in early social cognition. Although I applaud their theoretical framework, I argue that data from studies of human infants are not necessarily consistent with the developmental picture that they describe.

Carey proposes a theory of conceptual development that specifies innate conceptual representations that get learning started. Those representations are the output of innate domain-specific input analyzers. I contend that innate core cognition about agency is itself a gradual construction and that the role of Quinian bootstrapping needs elaboration to account for the development of intuitive theories of psychology.

This Hackett edition, first published in 1981, is an unabridged and unaltered republication of the seventh edition as published by Macmillan and Company, Limited. From the forward by John Rawls: In the utilitarian tradition Henry Sidgwick has an important place. His fundamental work, The Methods of Ethics, is the clearest and most accessible formulation of what we may call 'the classical utilitarian doctorine.' This classical doctrine holds that the ultimate moral end of social and individual action is the greatest net (...) sum of the happiness of all sentient beings. Happinesss is specified by the net balance of pleasure over pain, or, as Sidgwick preferred to say, as the net balance of agreeable over disagreeable consciousness.... (shrink)

Cet ouvrage n'est ni un commentaire ni une explication d'obedience historiciste ou deterministe. Par questionnement, lecture et interpretation, l'auteur a voulu produire une semantique philosophique. La doctrine des idees est ainsi reexaminee a la convergence des problemes du langage, de la science et de la cite (logos, episteme, polis). Elle ne peut plus des lors etre interpretee sous l'hypothese de l' idealisme. Elle se manifeste comme une serie de questions de sens ou s'indique une philosophie de la raison. Partout ou (...) le logos nous porte, c'est la qu'il faut aller, tel en serait le mot d'ordre, mais avec la precision qu'a l'articulation du mythique et du theorique, du tragique et du philosohique, et plus profondement de la deraison et du logos, le rationalisme platonicien n'est fait que de raison. (shrink)

Henry Home (1696-1782) has been called "perhaps the most complete 'Enlightenment man' among the eighteenth-century Scottish thinkers." Kinsman and friend of David Hume, mentor and patron of Adam Smith, John Millar, and Thomas Reid, he was a key figure in that circle of luminaries. He read law, was called to the bar in 1723, was raised to the Bench of the Court of Session in 1752, with the title Lord Kames (the name of his family estate), and joined the High (...) Court of the Justiciary in 1763. Publishing broadly in law, history, philosophy, and criticism, Kames made significant contributions to the Enlightenment's science of human nature. The Essays is commonly considered Kames's most important philosophical work. In the first part, he sets forth the principles and foundations of morality and justice, attacking Hume's moral skepticism and addressing the controversial issue of the freedom of human will. In the second part, Kames focuses on questions of metaphysics and epistemology to offer a natural theology in which the authority of the external senses is an important basis for belief in the Deity. The text of this volume is based on the third edition of 1779, while the appendix presents substantial variant readings in the first and second editions. (shrink)

Of all the developments in twentieth century physics, none has given rise to more heated debates than the changes in our understanding of science precipitated by the quantum revolution''. In this revolution, Niels Bohr's dramatically non-classical theory of the atom proved to be the springboard from which the new atomic physics drew it's momentum. Furthermore, Bohr's contribution was crucial not only because his interpretation of quantum mechanics became the most widely accepted view but also because in his role as educator (...) and spokesman for atomic physics Bohr was very much the patron spirit of the entire quantum revolution. The conceptual framework which he proposed to provide a new viewpoint for understanding the quantum theoretical description of atomic systems became for most of this century the dominant outlook of countless productive experimental and theoretical physicists. He called this new framework complementarity''. (shrink)

Available for the first time in English, this work explores a range of mental disorders in the context of Frankl's theory of human motivation. Skillfully translated and featuring extensive annotation, this English language edition remains true to the original while updating assessment and treatment protocols to be compatible with 21st century medicine. As the title suggests, On the Theory and Therapy of Mental Disorders applies a theoretical treatise to the practical treatment of variety of disorders. This long-awaited addition to the (...) body of English language literature introduces Viktor Frankl's clinical insights to a new generation of mental health professionals, and has much to offer to practitioners of all levels of experience. (shrink)

Expressing doubts about death criteria can serve healthy purposes, but can also cause a number of harms, including decreased organ donation rates and distress for donor families and health care staff. This paper explores the various causes of doubts about death criteria—including religious beliefs, misinformation, mistrust, and intellectual questions—and recommends responses to each of these. Some recommended responses are relatively simple and noncontroversial, such as providing accurate information. However, other responses would require significant changes to the way we currently do (...) business. Policymakers should establish minimum national standards for determining death to foster a trustworthy system; academics and publishers have a duty to publish only materials that substantially engage and advance the debate to minimize the harm caused by divided expert opinion; and opposition to the dead donor rule should be conceptually separated from doubts about death criteria. (shrink)