Hypothetical queries are queries embedding hypotheses about the database. The embedded hypothesis in a hypothetical query indicates, so to say, a state of the database intended for the rest of the query. Thus the answer to a hypothetical query h > q, with a hypothesis h, is in principle the result of evaluating q against the database revised with h. In case h is inconsistent with the database, ...

The initial part of this paper explores and rejects three standard views of how scientific laws might be systematically connected with physical necessity or possibility. The first concerns laws and their consequences, the second concerns the so-called counterfactual connection, and the third concerns a possible worlds construction of physical necessity. The remaining part introduces a neglected...

Three categories, varying from lowest to highest levels of abstraction, of possible relationships between psychology and literature are critically examined. The first category represents the lowest level of abstraction and involves ‘psychology in literature’: literature as a source of psychological data; literature as a source of insights for psychology. The second involves literature as an ind...

The article investigates the sceptical challenge from an information-theoretic perspective. Its main goal is to articulate and defend the view that either informational scepticism is radical, but then it is epistemologically innocuous because redundant; or it is moderate, but then epistemologically beneficial because useful. In order to pursue this cooptation strategy, the article is divided in...

In (Petrick and Bacchus 2002), a “knowledge-level” approach to planning under incomplete knowledge and sensing was presented. In comparison with alternate approaches based on representing sets of possible worlds, this higher-level representation is richer, but the inferences it supports are weaker. Nevertheless, because of its richer representation, it is able to solve problems that cannot be s...

The possible worlds model and its associated Kripkean semantics provide an intuitive semantics to epistemic logics, but they seem to commit us to model agents which are logically omniscient and perfect reasoners. In this article we show that this is not necessarily the case, if possible worlds are not considered as consistent descriptions of the real world. We propose to model the beliefs of an...

Our understanding of subjunctive conditionals has been greatly enhanced through the use of possible world semantics and, more precisely, by the idea that they involve variably strict quantification over possible worlds. I propose to extend this treatment to ceteris paribus conditionals – that is, conditionals that incorporate a ceteris paribus or ‘other things being equal’ clause. Although such...

Observing the actions of other people allows us to learn not only about their mental states, but also about hidden aspects of a shared environmental situation – things we cannot see, but they can, and that influence their behavior in predictable ways. This paper presents a computational model of how people can learn about the world through these social inferences, supported by the same Theory o...

Invariance is one of the most important notions in applications of mathematics. It is one of the key concepts in modern physics, is a computational tool that helps in solving complex equations, etc. In view of its importance, it is desirable to come up with a definition of invariance which is as general as possible. In this paper, we describe how to formulate a general notion of invariance in c...

In this paper we consider a logic programming framework for reasoning about imprecise probabilities. In particular, we propose a new semantics, for the Probabilistic Logic Programs (p-programs) of Ng and Subrahmanian. Pprograms represent imprecision using probability intervals. Our semantics, based on the possible worlds semantics, considers all point probability distributions that satisfy a gi...