David Lewis has recently developed the notion of conversational scorekeeping as a way of explaining the acceptability of utterances in various contexts and the manner in which this acceptability changes in a rule-governed manner. I will expand Lewis's discussion by showing how the acceptibility of conditionals is linked to conversational score. In particular, I will argue that at least one controversial issue concerning the logic of conditionals, the interpretation and use of conditionals with disjunctive antecedents, may be resolved by applying (...) Lewis's notion of an accommodation rule for conversational scorekeeping. (shrink)

Relevant to philosophy, law, management, and artificial intelligence, these papers explore the applicability of nonmonotonic or defeasible logic to normative reasoning. The resulting systems purport to solve well-known deontic paradoxes and to provide a better treatment than classical deontic logic does of prima facie obligation, conditional obligation, and priorities of normative principles.

Searle’s Chinese room argument (CRA) was recently charged as being unsound because it makes a logical error. It is shown here that this charge is based on a misinterpretation of the modal scope of a major premise of the CRA and that the CRA does not commit the logical error with which it is charged.

Fixpoint semantics are provided for ambiguity blocking and propagating variants of Nute's defeasible logic. The semantics are based upon the well-founded semantics for logic programs. It is shown that the logics are sound with respect to their counterpart semantics and complete for locally finite theories. Unlike some other nonmonotonic reasoning formalisms such as Reiter's default logic, the two defeasible logics are directly skeptical and so reject floating conclusions. For defeasible theories with transitive priorities on defeasible rules, the logics are shown (...) to satisfy versions of Cut and Cautious Monotony. For theories with either conflict sets closed under strict rules or strict rules closed under transposition, a form of Consistency Preservation is shown to hold. The differences between the two logics and other variants of defeasible logic—specifically those presented by Billington, Antoniou, Governatori, and Maher—are discussed. (shrink)

It is argued that ockham's theory of language either fails to provide a principle of individuation to account for the diversity of mental entities he posits or is committed to certain spoken terms both having and not having some one entity as a significant. It is suggested that this problem can be solved by allowing that every categorematic term is subordinated to an infinite number of concepts and by modifying ockham's supposition theory.

This article is a comment on barry miller, "proper names and their distinctive senses," "australian journal of philosophy", Volume 52, Pages 201-210, January 1974. Miller claims that the sense of a name is its role of referring to the individual to which it has been attached in the act of naming. Miller also claims that names have unique senses and that it is impossible in principle to say what these senses are. Here it is shown that these claims are incompatible. (...) Miller's account of the senses of names also results in the problem which frege's distinction between sense and reference was intended to solve. (shrink)

Many philosophers have claimed possible worlds semantics is incoherent because of insoluble problems involved in the notion of identifying a single individual in different worlds. One frequent approach to trans-world identification has been to assume that all the possible worlds, complete with their populations, are described by means of qualities alone prior to our considering the question of identification of the same individual in each world in which it exists. If we interpret possible worlds semantics in this way, trans-world identification (...) could only be accomplished on the basis of some properties the individual has uniquely in every world in which it exists. This becomes problematic since the individual doesn't have the same properties in every world. In ‘Naming and Necessity’ and ‘Identity and Necessity’ Saul Kripke rejects such an account of both possible worlds and trans-world identification, developing an alternative interpretation of the new semantics. His approach involves a distinction between referring expressions which designate different individuals in different worlds according to the distribution of properties within each world and referring expressions which designate the same individual in every world. (shrink)

This is a review of CONDITIONALS: FROM PHILOSOPHY TO COMPUTER SCIENCE, edited by Crocco G., del Cerro L. Fariñas, and Herzig A., Studies in logic and computation, no. 5, Clarendon Press, Oxford University Press, Oxford and New York 1995.