The Monty Hall Problem (MHP), a process of two-stage decision making, was presented in atypical form via a custom software game. Differing from the normal three-box MHP, the game added one additional box on-screen for each game—culminating on game 23 with 25 on-screen boxes to initially choose from. A total of 108 participants played 23 games (trials) in one of four conditions; (1) “Vanish” condition—all non-winning boxes totally removed from the screen; (2) “Empty” condition—all non-winning boxes remain on-screen, but with (...) an “empty” label on them; (3) “Steroids” condition—all non-winning boxes removed from the screen, with initially chosen box becoming 25% larger; (4) “Steroids2” condition—all non-winning boxes removed from the screen, box not currently chosen becomes 25% larger. Results indicate second-stage on-screen presence of boxes influences switching; with their absence having the opposite effect. Size manipulation appears to elicit demand characteristics resulting in indeterminate influence. (shrink)
The twelve contributors to Looking for Los Angeles focus on dramatic shifts in the urban landscape, important moments in the city's architectural history, and the role of the image in this mecca of image makers.
Counterfactual imaginings are known to have far reaching implications. In the present experiment, we ask if imagining events from one's past can affect memory for childhood events. We draw on the social psychology literature showing that imagining a future event increases the subjective likelihood that the event will occur. The concepts of cognitive availability and the source monitoring framework provide reasons to expect that imagination may inflate confidence that a childhood event occurred. However, people routinely produce myriad counterfactual imaginings (i.e., (...) daydreams and fantasies) but usually do not confuse them with past experiences. To determine the effects of imagining a childhood event, we pretested subjects on how confident they were that a number of childhood events had happened, asked them to imagine some of those events, and then gathered new confidence measures. For each of the target items, imagination inflated confidence that the event had occurred in childhood. We discuss implications for situations in which imagination is used as an aid in searching for presumably lost memories. (shrink)
We show that the implicational fragment of intuitionism is the weakest logic with a non-trivial probabilistic semantics which satisfies the thesis that the probabilities of conditionals are conditional probabilities. We also show that several logics between intuitionism and classical logic also admit non-trivial probability functions which satisfy that thesis. On the other hand, we also prove that very weak assumptions concerning negation added to the core probability conditions with the restriction that probabilities of conditionals are conditional probabilities are sufficient to (...) trivialize the semantics. (shrink)
Conclusions reached using common sense reasoning from a set of premises are often subsequently revised when additional premises are added. Because we do not always accept previous conclusions in light of subsequent information, common sense reasoning is said to be nonmonotonic. But in the standard formal systems usually studied by logicians, if a conclusion follows from a set of premises, that same conclusion still follows no matter how the premise set is augmented; that is, the consequence relations of standard logics (...) are monotonic. Much recent research in AI has been devoted to the attempt to develop nonmonotonic logics. After some motivational material, we give four formal proofs that there can be no nonmonotonic consequence relation that is characterized by universal constraints on rational belief structures. In other words, a nonmonotonic consequence relation that corresponds to universal principles of rational belief is impossible. We show that the nonmonotonicity of common sense reasoning is a function of the way we use logic, not a function of the logic we use. We give several examples of how nonmonotonic reasoning systems may be based on monotonic logics. (shrink)
In  Hempel and Oppenheim give a definition of “explanation” for a certain formal language. In  Eberle, Kaplan, and Montague prove five theorems demonstrating that the Hempel and Oppenheim definition is not restrictive enough. In  Kim proposes two further conditions to supplement the Hempel and Oppenheim definition in order to avoid the objections posed in . In this paper it is shown that the definition of Hempel and Oppenheim supplemented by Kim's conditions is open to a trivialization very (...) analogous to that given in . (shrink)
The usual semantics for the modal systems T, S4, and S5 assumes that the set of possible worlds contains at least one member. Recently versions of these modal systems have been developed in which this assumption is dropped. The systems discussed here are obtained by slightly weakening the liberated versions of T and S4. The semantics does not assume the existence of possible worlds, and the accessibility relation between worlds is only required to be quasi-reflexive instead of reflexive. Completeness and (...) independence results are established. (shrink)
Erasmus’s Adages were among his most influential works in his own time, particularly later editions, which included both Greek and Latin. In the adages included in volumes 35 and 36, Erasmus criticizes secular and ecclesiastical life, commenting on topics such as war, reform of the church and spiritual life, and the corrupting effects of the relentless pursuit of wealth and power. Erasmus aims his narrative and commentary in Paraphrase on the Gospel of Matthew (volume 45) at a general educated audience (...) (rather than professional theologians). Together, these volumes provide readable and accurate edition of Erasmus’s work and helpful special indexes. (shrink)
In this paper we examine the thesis that the probability of the conditional is the conditional probability. Previous work by a number of authors has shown that in standard numerical probability theories, the addition of the thesis leads to triviality. We introduce very weak, comparative conditional probability structures and discuss some extremely simple constraints. We show that even in such a minimal context, if one adds the thesis that the probability of a conditional is the conditional probability, then one trivializes (...) the theory. Another way of stating the result is that the conditional of conditional probability cannot be represented in the object language on pain of trivializing the theory. (shrink)
The intuitive notion behind the usual semantics of most systems of modal logic is that of ?possible worlds?. Loosely speaking, an expression is necessary if and only if it holds in all possible worlds; it is possible if and only if it holds in some possible world. Of course, contradictory expressions turn out to hold in no possible worlds, and logically true expressions turn out to hold in every possible world. A method is presented for transforming standard modal systems into (...) systems of modal logic for impossible worlds. To each possible world there corresponds an impossible world such that an expression holds in the impossible world if and only if it does not hold in the possible world. One can then talk about such worlds quite consistently, and there seems to be no logical reason for excluding them from consideration. (shrink)
Abstract The increasing prevalence of armed drones in the conduct of military operations has generated robust debate. Among legal scholars, the crux of the dispute generally pits those who herald the new technology's unparalleled precision against those who view such newfound capabilities as an inducement to employ excessive force. Largely overlooked in the discussion over how drone strikes can be accomplished lawfully is a more fundamental question: Can a model of warfare that eschews any risk of harm to one party (...) be squared with the ethical framework that informs the law of war? This matter has less to do with the technology per se than with a policy orientation that utilizes such technology as a strategy in itself, as opposed to one military tool in a larger arsenal. A corollary to the incongruity of riskless warfare is to query whether the ensuing breakdown of ethical and legal norms unwittingly encourages the very instability that the law of war attempts to control, thereby endangering the civilian populations of all parties to the conflict. While other authors have previously addressed the challenges posed by asymmetry to the law of armed conflict in different formats, this article explores these issues through a hypothetical scenario and seeks to elucidate some of the potential ramifications of the pursuit of physical impunity in war. (shrink)
Almost every formal model of explanation thus far proposed has been demonstrated to be faulty. In this paper, a new model, proposed by Raimo Tuomela, is also demonstrated to be faulty. In particular, one condition of the model is shown to be too restrictive, and another condition of the model is shown to be too permissive.