Reasoning with inconsistent possibilistic description logics ontologies with disjunctive assertions

We present a preliminary framework for reasoning with possibilistic description logics ontologies with disjunctive assertions (PoDLoDA ontologies for short). Given a PoDLoDA ontology, its terminological box is expressed in the description logic programming fragment but its assertional box allows four kinds of statements: an individual is a member of a concept, two individuals are related through a role, an individual is a member of the union of two or more concepts or two individuals are related through the union of two or more roles. Axioms and statements in PoDLoDA ontologies have a numerical certainty degree attached. A disjunctive assertion expresses a doubt respect to the membership of either individuals to union of concepts or pairs of individuals to the union of roles. Because PoDLoDA ontologies allow to represent incomplete and potentially inconsistent information, instance checking is addressed through an adaptation of Bodanza’s Suppositional Argumentation System that allows to reason with modus ponens and constructive dilemmas. We think that our approach will be of use for implementers of reasoning systems in the Semantic Web where uncertainty of membership of individuals to concepts or roles is present.Facultad de Informátic

Rationality, pragmatics, and sources

This thesis contributes to the Great Rationality Debate in cognitive science. It introduces and explores a triangular scheme for understanding the relationship between rationality and two key abilities: pragmatics – roughly, inferring implicit intended utterance meanings – and learning from sources. The thesis argues that these three components – rationality, pragmatics, and sources – should be considered together: that each one informs the others. The thesis makes this case through literature review and theoretical work (principally, in Chapters 1 and 8) and through a series of empirical chapters focusing on different parts of the triangular scheme. Chapters 2 to 4 address the relationship between pragmatics and sources, focusing on how people change their beliefs when they read a conditional with a partially reliable source. The data bear on theories of the conditional and on the literature assessing people’s rationality with conditionals. Chapter 5 addresses the relationship between rationality and pragmatics, focusing on conditionals ‘in action’ in a framing effect known as goal framing. The data suggest a complex relationship between pragmatics and utilities, and support a new approach to goal framing. Chapter 6 addresses the relationship between rationality and sources, using normative Bayesian models to explore how people respond to simple claims from sources of different reliabilities. The data support a two-way relationship between claims and source information and, perhaps most strikingly, suggest that people readily treat sources as ‘anti-reliable’: as negatively correlated with the truth. Chapter 7 extends these experiments to test the theory that speakers can guard against reputational damage using hedging. The data do not support this theory, and raise questions about whether trust and vigilance against deception are prerequisites for pragmatics. Lastly, Chapter 8 synthesizes the results; argues for new ways of understanding the relationships between rationality, pragmatics, and sources; and relates the findings to emerging formal methods in psychology

A Stalnakerian Analysis of Metafictive Statements

Because Stalnaker’s common ground framework is focussed on cooperative information exchange, it is challenging to model fictional discourse. To this end, I develop an extension of Stalnaker’s analysis of assertion that adds a temporary workspace to the common ground. I argue that my framework models metafictive discourse better than competing approaches that are based on adding unofficial common grounds

Explaining Imagination

Imagination will remain a mystery—we will not be able to explain imagination—until we can break it into simpler parts that are more easily understood. Explaining Imagination is a guidebook for doing just that, where the simpler parts are other familiar mental states like beliefs, desires, judgments, decisions, and intentions. In different combinations and contexts, these states constitute cases of imagining. This reductive approach to imagination is at direct odds with the current orthodoxy, which sees imagination as an irreducible, sui generis mental state or process—one that influences our judgments, beliefs, desires, and so on, without being constituted by them. Explaining Imagination looks closely at the main contexts where imagination is thought to be at work and argues that, in each case, the capacity is best explained by appeal to a person’s beliefs, judgments, desires, intentions, or decisions. The proper conclusion is not that there are no imaginings after all, but that these other states simply constitute the relevant cases of imagining. Contexts explored in depth include: hypothetical and counterfactual reasoning, engaging in pretense, appreciating fictions, and generating creative works. The special role of mental imagery within states like beliefs, desires, and judgments is explained in a way that is compatible with reducing imagination to more basic folk psychological states. A significant upshot is that, in order to create an artificial mind with an imagination, we need only give it these more ordinary mental states