Neste artigo, Bar-Hillel e Carnap apresentam pela primeira vez as ideias básicas de uma teoria da informação semântica. O conceito de informação, baseado em sentença declarativa em uma dada linguagem, é definido pelo conteúdo descritivo expresso pelas sentenças. A quantidade de informação é calculada com base em um conjunto de funções lógicas probabilísticas sobre conjuntos de conteúdos descritíveis. Esta teoria tem aplicabilidade dedutiva e indutiva, significando um marco para o desenvolvimento das teorias filosóficas da informação.

In June 22-27,1970, an International Working Symposium on Pragmatics of Natural Languages took place in Jerusalem under the auspices of The Israel Academy of Sciences and Humanities and the Division of Logic, Methodology and Philosophy of Science of the International Union of History and Philosophy of Science.! Some thirty philosophers, logicians, linguists, and psychologists from Israel, U.S.A., West-Germany, England, Belgium, France, Scotland, and Denmark met in seven formal and a number of informal sessions in order to discuss some ofthe problems (...) around the use and acquisition oflanguage which in the eyes of an increasing number of scholars have been left under treated in the recent upsurge ofinterest in theoretical linguistics and philos ophy of language. More specifically, during the formal sessions the following topics were discussed: The validity of the syntactics-seman tics-pragmatics trichotomy The present state of the competence-performance issue Logic and linguistics The New Rhetoric Speech acts Language acquisition. The participants in the Symposium distributed among themselves re prints and preprints of relevant material, partly in advance of the meeting, partly at its beginning. Each session was introduced by one or two modera tors, and summaries of each day's proceedings were prepared and distri buted the next day. The participants were invited to submit papers after the symposium, written under its impact. The eleven essays published here are the result. (shrink)

Subjects were requested to choose between gambles, where the outcome of one gamble depended on a single elementary event, and the other depended on an event compounded of a series of such elementary events. The data supported the hypothesis that the subjective probability of a compound event is systematically biased in the direction of the probability of its components resulting in overestimation of conjunctive events and underestimation of disjunctive events. Studies pertaining to this topic are discussed.

The concepts of supportive evidence and of relevant evidence seem very closely related to each other. Supportive evidence is clearly always relevant as well. But must relevant evidence be defined as evidence which is either supportive or weakeking? In an explicit or implicit manner, this is indeed the position of many philosophers. The paradox of ideal evidence, however, shows us that this is to restrictive. Besides increasing or decreasing the probability attached to some hypothesis, evidence can alter or interact with (...) the background assumptions underlying the hypothesis.In most circumstances, the (post hoc) relevance of evidence can indeed be judged by its effect on the confidence one attaches to hypotheses. Occasionally, as in the circumstances described by Example I, and more generally called “the Paradox of Ideal Evidence”, the relevance of evidence to an hypothesis can only be understood by appeal to a broader sense. (shrink)