Can the output of human cognition be predicted from the assumption that it is an optimal response to the information-processing demands of the environment? A methodology called rational analysis is described for deriving predictions about cognitive phenomena using optimization assumptions. The predictions flow from the statistical structure of the environment and not the assumed structure of the mind. Bayesian inference is used, assuming that people start with a weak prior model of the world which they integrate with experience to develop (...) stronger models of specific aspects of the world. Cognitive performance maximizes the difference between the expected gain and cost of mental effort. Memory performance can be predicted on the assumption that retrieval seeks a maximal trade-off between the probability of finding the relevant memories and the effort required to do so; in categorization performance there is a similar trade-off between accuracy in predicting object features and the cost of hypothesis formation; in casual inference the trade-off is between accuracy in predicting future events and the cost of hypothesis formation; and in problem solving it is between the probability of achieving goals and the cost of both external and mental problem-solving search. The implemention of these rational prescriptions in neurally plausible architecture is also discussed. (shrink)

LAS is a program that acquires augmented transition network (ATN) grammars. It requires as data sentences of the language and semantic network representatives of their meaning. In acquiring the ATN grammars, it induces the word classes of the language, the rules of formation for sentences, and the rules mapping sentences onto meaning. The induced ATN grammar can be used both for sentence generation and sentence comprehension. Critical to the performance of the program are assumptions that it makes about the relation (...) between sentence structure and surface structure (the graph deformation condition), about when word classes may be formed and when ATN networks may be merged, and about the structure of noun phrases. These assumptions seem to be good heuristics which are largely true for natural languages although they would not be true for many nonnatural languages. Provided these assumptions are satisfied LAS seems capable of learning any context‐free language. (shrink)

In this paper we shall answer some questions in the set theory of L, the universe of all sets constructible from the reals. In order to do so, we shall assume ADL, the hypothesis that all 2-person games of perfect information on ω whose payoff set is in L are determined. This is by now standard practice. ZFC itself decides few questions in the set theory of L, and for reasons we cannot discuss here, ZFC + ADL yields the most (...) interesting “completion” of the ZFC-theory of L.ADL implies that L satisfies “every wellordered set of reals is countable”, so that the axiom of choice fails in L. Nevertheless, there is a natural inner model of L, namely HODL, which satisfies ZFC.. The superscript “L” indicates, here and below, that the notion in question is to be interpreted in L.) HODL is reasonably close to the full L, in ways we shall make precise in § 1. The most important of the questions we shall answer concern HODL: what is its first order theory, and in particular, does it satisfy GCH?These questions first drew attention in the 70's and early 80's. (shrink)

Will enable the ordinary person to discover his or her own unique life myth and live it from moment to moment.

In this paper an argument by l j jost against the use of j o urmson's concept of central illocutionary force to support a speech act analysis of meaning is rejected on the grounds that jost misinterprets urmson's concept, but it is further argued that the concept correctly interpreted is still of little use because it provides no way of picking out the word whose meaning it explicates.

Michael Wheeler, in his book Reconstructing the Cognitive World, analyses the development of embedded-embodied cognitive science in the light of underlying philosophical differences about the constitution of human agency. On one side he sees orthodox computational cognitive science as holding to Cartesian conceptions of an abstract, disembodied reason deliberating over de-contextualised representations of the world. On the other side, he sees modern-day embodied-embedded cognitive scientists going beyond such Cartesianism to embrace concepts of human agency more in keeping with Heidegger’s account (...) of Dasein in Being and Time. By bringing to light and criticising the Cartesian assumptions of the computationalists and by pointing out and clarifying the connections between embodied-embedded cognitive science and Heidegger’s philosophy, Wheeler aims to lay the “foundations of a genuinely non- Cartesian cognitive science.”. (shrink)

Among the greatest challenges to improving health is determining how cultural diversity should influence healthcare practices and organizations, public health measures, biomedical research, and community partnering. Important but seldom addressed are challenges for bioethicists.

Democracy is more than a collection of institutions, laws, and freely contested sources of authority. It is also an ideal. If we think of this ideal in republican terms, in terms of resistance to domination through the practices of mutual accountability, and if we recall that democratic life invariably comes with loss, then those of us who inhabit a democratic political society will need to locate, and then cultivate, responses to loss that do not undermine our commitment to this ideal. (...) Tolerance, one such response, is widely recognized and yet poorly theorized. Thomas Aquinas did not recognize it, but he did praise and endorse its act, toleration, and he does offer resources for bringing the virtue into focus and identifying some of the distinguishing features of its democratic variant. (shrink)

Red-2 is a computer program for red-cell antibody identification, a piece of "normal science". Abstracting from Red-2, a general problem solving mechanism is described that is especially suited for performing a form of abductive inference or best explanation finding. A problem solver embodying this mechanism synthesizes composite hypotheses by combining hypothesis parts. This is a common task of intelligence, and a component of scientific reasoning. The work addresses the question, 'How is science possible?' by showing how a simple but powerful (...) form of hypothesis synthesis is computationally feasible. (shrink)