Local Change

An agent can usually hold a very large number of beliefs. However, only a small part of these beliefs is used at a time. Efficient operations for belief change should affect the beliefs of the agent locally, that is, the changes should be performed only in the relevant part of the belief state. In this paper we define a local consequence operator that only considers the relevant part of a belief base. This operator is used to define local versions of the operations for belief change. Representation theorems are given for the local operators.     

Vibrotactile frequency discrimination

Thresholds for vibrotactile discrimination of pulse interval were determined for pulse frequencies between 1 and 384 Hz. The results point to a temporal resolution significantly more accurate than that demonstrated in earlier studies. Although touch as a vibratory sensor is in general much inferior to audition, the present results show a striking resemblance to those obtained on auditory pitch. The neurophysiological implications for the tactile as well as for the auditory system are discussed.     

Uncertainty and the Ethics of Clinical Trials

A probabilistic explication is offered of equipoise and uncertainty in clinical trials. In order to be useful in the justification of clinical trials, equipoise has to be interpreted in terms of overlapping probability distributions of possible treatment outcomes, rather than point estimates representing expectation values. Uncertainty about treatment outcomes is shown to be a necessary but insufficient condition for the ethical defensibility of clinical trials. Additional requirements are proposed for the nature of that uncertainty. The indecisiveness of our criteria for cautious decision-making under uncertainty creates the leeway that makes clinical trials defensible.     

Reading words with irregular decoding rules: A test of premorbid cognitive function?

The present study investigated the relation between level of general cognitive function and the oral reading of irregular words in Swedish. Swedish is an orthographically regular language, so many irregular words are loan words from other languages. A test comprising such words (irregularly spelled words (ISW)) was designed, and tested on a sample of 48 healthy Swedish adults, stratified according to age, gender, and level of education. The results confirmed that the ability to read words that do not follow the regular rules for decoding in Swedish was positively related to general cognitive level. ISW in combination with demographic variables gave a good estimate of general cognitive function and a better estimate than demographic variables alone. Exposure to written and spoken vocabulary during the lifespan may be indexed by ISW performance, for factor analysis suggested that this may constitute a discrete factor contributing to cognitive function.     

What is ceteris paribus preference?

A general format is introduced for deriving preferences over states of affairs from preferences over a set of contextually complete alternatives. Formal results are given both for this general format and for a specific instance of it that is a plausible explication of ceteris paribus prefence.     

A note on the deontic system DL of Jones and Pörn

I would like to thank Ingmar Pörn for valuable comments on an earlier version of this paper.     

John Stuart Mill and the Conflicts of Equality

John Stuart Mill commented on the relationship between equality and liberty in general terms, and he also discussed the relationships between equality and four more concrete social goals: equality vs. diversity and individual spontaneity, equality vs. freedom of trade and entrepreneurial activity, equality vs. economic incentives for workpeople, and equality vs. welfare. In his more general statements he wrote off potential conflicts between equality and liberty, claiming that only those liberties that can be enjoyed by all are real liberties—or at least they are the only ones worth defending. However, in several of his more concrete discussions he gave higher priority to various liberty-related goals than to equality. This seeming contradiction can be resolved if we assume that he distinguished between valuing a liberty per se and valuing it as a means to achieve something else.

     

The Moral Oracle’s Test

When presented with a situation involving an agent’s choice between alternative actions, a moral oracle says what the agent is allowed to do. The oracle bases her advice on some moral theory, but the nature of that theory is not known by us. The moral oracle’s test consists in determining whether a series of questions to the oracle can be so constructed that her answers will reveal which of two given types of theories she adheres to. The test can be applied to moral theories in order to determine if they differ in their recommendations for action. Based on this test, a terminology is developed to specify different forms and degrees of distinguishability between moral theories, or types of theories, in terms of their recommendations for action. In conclusion, the test is applied to consequentialism and utilitarianism.     

Maximal and perimaximal contraction

Generalizations of partial meet contraction are introduced that start out from the observation that only some of the logically closed subsets of the original belief set are at all viable as contraction outcomes. Belief contraction should proceed by selection among these viable options. Several contraction operators that are based on such selection mechanisms are introduced and then axiomatically characterized. These constructions are more general than the belief base approach. It is shown that partial meet contraction is exactly characterized by adding to one of these constructions the condition that all logically closed subsets of the belief set can be obtained as the outcome of a single (multiple) contraction. Examples are provided showing the counter-intuitive consequences of that condition, thus confirming the credibility of the proposed generalization of the AGM framework.     

Consuming experience: Why affective forecasters overestimate comparative value

The hedonic value of an outcome can be influenced by the alternatives to which it is compared, which is why people expect to be happier with outcomes that maximize comparative value (e.g., the best of several mediocre alternatives) than with outcomes that maximize absolute value (e.g., the worst of several excellent alternatives). The results of five experiments suggest that affective forecasters overestimate the importance of comparative value because forecasters do not realize that comparison requires cognitive resources, and that experiences consume more cognitive resources than do forecasts. In other words, because forecasters overestimate the extent to which they will be able to think about what they did not get while experiencing what they got.