493 research outputs found

    The inheritance of dynamic and deontic integrity constraints or: Does the boss have more rights?

    Get PDF
    In [18,23], we presented a language for the specification of static, dynamic and deontic integrity constraints (IC's) for conceptual models (CM's). An important problem not discussed in that paper is how IC's are inherited in a taxonomic network of types. For example, if students are permitted to perform certain actions under certain preconditions, must we repeat these preconditions when specializing this action for the subtype of graduate students, or are they inherited, and if so, how? For static constraints, this problem is relatively trivial, but for dynamic and deontic constraints, it will turn out that it contains numerous pitfalls, caused by the fact that common sense supplies presuppositions about the structure of IC inheritance that are not warranted by logic. In this paper, we unravel some of these presuppositions and show how to avoid the pitfalls. We first formulate a number of general theorems about the inheritance of necessary and/or sufficient conditions and show that for upward inheritance, a closure assumption is needed. We apply this to dynamic and deontic IC's, where conditions arepreconditions of actions, and show that our common sense is sometimes mistaken about the logical implications of what we have specified. We also show the connection of necessary and sufficient preconditions of actions with the specification of weakest preconditions in programming logic. Finally, we argue that information analysts usually assume constraint completion in the specification of (pre)conditions analogous to predicate completion in Prolog and circumscription in non-monotonic logic. The results are illustrated with numerous examples and compared with other approaches in the literature

    Forgetting complex propositions

    Full text link
    This paper uses possible-world semantics to model the changes that may occur in an agent's knowledge as she loses information. This builds on previous work in which the agent may forget the truth-value of an atomic proposition, to a more general case where she may forget the truth-value of a propositional formula. The generalization poses some challenges, since in order to forget whether a complex proposition π\pi is the case, the agent must also lose information about the propositional atoms that appear in it, and there is no unambiguous way to go about this. We resolve this situation by considering expressions of the form [π]φ[\boldsymbol{\ddagger} \pi]\varphi, which quantify over all possible (but minimal) ways of forgetting whether π\pi. Propositional atoms are modified non-deterministically, although uniformly, in all possible worlds. We then represent this within action model logic in order to give a sound and complete axiomatization for a logic with knowledge and forgetting. Finally, some variants are discussed, such as when an agent forgets π\pi (rather than forgets whether π\pi) and when the modification of atomic facts is done non-uniformly throughout the model

    Questioning the causal inheritance principle

    Get PDF
    Mental causation, though a forceful intuition embedded in our commonsense psychology, is difficult to square with the rest of commitments of physicalism about the mind. Advocates of mental causation have found solace in the causal inheritance principle, according to which the mental properties of mental states share the causal powers of their physical counterparts. In this paper, I present a variety of counterarguments to causal inheritance and conclude that the requirements for causal inheritance are stricter than what standing versions of said principle imply. In line with this, physicalism may be destined to epiphenomenalism unless multiple realizability turns out false

    On the logic of theory change: contraction without recovery

    Get PDF
    The postulate of Recovery, among the six postulates for theory contraction, formulated and studied by Alchourron, G ´ ardenfors and Makinson is the one that has provoked most controversy. ¨ In this article we construct withdrawal functions that do not satisfy Recovery, but try to preserve minimal change, and relate these withdrawal functions with the AGM contraction functions.info:eu-repo/semantics/publishedVersio

    Bakhtin as a theory of reading

    Get PDF
    Includes bibliographical references (p. 20

    Knowledge and the Importance of Being Right

    Get PDF
    Some philosophers have recently argued that whether a true belief amounts to knowledge in a specific circumstance depends on features of the subject’s practical situation that are unrelated to the truth of the subject’s belief, such as the costs for the subject of being wrong about whether the believed proposition is true. One of the best-known arguments used to support this view is that it best explains a number of paradigmatic cases, such as the well-known Bank Case, in which a difference in knowledge occurs in subjects differing exclusively with respect to their practical situation. I suggest an alternative explanation of such cases. My explanation has a disjunctive character: on the one hand, it accounts for cases in which the subject is aware of the costs of being wrong in a given situation in terms of the influence of psychological factors on her mechanisms of belief-formation and revision. On the other hand, it accounts for cases in which the subject is ignorant of the costs of being wrong in her situation by imposing a new condition on knowledge. This condition is that one knows that p only if one does not underestimate the importance of being right about whether p. I argue that my explanation has a number of advantages over other invariantist explanations: it accounts for all the relevant cases preserving the semantic significance of our ordinary intuitions, it is compatible with an intellectualist account of knowledge and it escapes several problems affecting competing views

    Second order properties: Why Kim's reduction does not work

    Get PDF
    corecore