Hempel's paradox of the ravens has to do with the question of what constitutes confirmation from a logical point of view; Wason 's selection task has been used extensively to investigate how people go about attempting to confirm or disconfirm conditional claims. This paper presents an argument that the paradox is resolved, and that people's typical performance in the selection task can be explained, by consideration of what constitutes an effective strategy for seeking evidence of the tenability of universal or (...) conditional claims in everyday life. (shrink)

This book reviews the work of prominent psychologists and philosophers on conditional reasoning. It provides empirical research on how people deal with conditional arguments and examines how conditional statements are used and interpreted in everyday communication.

ABSTRACTTreating conditionals as probabilistic statements has been referred to as a defining feature of the “new paradigm” in cognitive psychology. Doing so is attractive for several reasons, but it complicates the problem of assessing the merits of conditional arguments. We consider several variables that relate to judging the persuasiveness of conditional arguments with uncertain premises. We also explore ways of judging the consistency of people's beliefs as represented by components of conditional arguments. Experimental results provide evidence that inconsistencies in beliefs (...) are more prevalent if the arguments’ components are spatially and temporally dispersed than if they are contiguous in space and time. This supports the idea that assuring the consistency among even a small number of beliefs is difficult to do, especially if the beliefs in question are not brought into consciousness at the same time; but consistency can be enhanced when beliefs are considered simultaneously or nea... (shrink)

The term “exchange paradox” refers to a situation in which it appears to be advantageous for each of two holders of an envelope containing some amount of money to always exchange his or her envelope for that of the other individual, which they know contains either half or twice their own amount. We review several versions of the problem and show that resolving the paradox depends on the specifics of the situation, which must be disambiguated, and on the player's beliefs. (...) The latter psychological variables are part and parcel of the resolution. Assuming reasonable subjective distributions, exchanging cannot always be advantageous for both players. We suggest several deep-rooted psychological reasons for the considerable difficulty people demonstrably have in dealing with this problem. Implicit widespread and compelling assumptions—that affect judgement in diverse contexts—obstruct the solution. Analysing this paradox underscores the close connection between psychology and probability theory. (shrink)

The “exchange paradox”—also referred to in the literature by a variety of other names, notably the “two-envelopes problem”—is notoriously difficult, and experts are not all agreed as to its resolution. Some of the various expressions of the problem are open to more than one interpretation; some are stated in such a way that assumptions are required in order to fill in missing information that is essential to any resolution. In three experiments several versions of the problem were used, in each (...) of which the information given was sufficient to determine an optimal choice strategy when it exists or to justify indifference regarding keeping or trading when such a strategy does not exist. College students who were presented with the various versions of the problem tended to base their choices on simple heuristics and to give little evidence of understanding the probabilistic implications of the differences in the problem statements. (shrink)

Drawing from the study of human reasoning, Argumentation describes different types of arguments and explains how they influence beliefs and behaviour. Raymond Nickerson identifies many of the fallacies, biases, and other flaws often found in arguments as well as 'stratagems' that people regularly use to persuade others. Much attention is given to the evaluation of arguments. Readers will learn a new schematic for evaluating arguments based on cognitive science. As a source for understanding and evaluating arguments in decision-making, (...) it is ideal for courses on cognition, reasoning, and psychology. (shrink)

The "two-envelopes" problem has stimulated much discussion on probabilistic reasoning, but relatively little experimentation. The problem specifies two identical envelopes, one of which contains twice as much money as the other. You are given one of the envelopes and the option of keeping it or trading for the other envelope. Variables of interest include the possible amounts of money involved, what is known about the process by which the amounts of money were assigned to the envelopes, and whether you are (...) allowed to know how much money is in the envelope in hand before deciding whether to keep or trade. In an earlier study, Butler and Nickerson found that when participants were allowed to know how much was in the envelope in hand, they generally elected to trade if that amount was small relative to the range of possibilities and to keep otherwise. The present experiments showed that this propensity was independent of the amount of money in the envelopes. Participants made decisions with a strong bias for avoiding the risk of losing by trading, particularly when the amount in hand was known and large relative to the range of possible amounts, regardless of the absolute value of the gamble. The results illustrate the dependence of thinking on the context in which it occurs, and demonstrate a tendency to treat quantities that are large or small relative to a particular context in which they are encountered as though they were large or small in a more general sense. (shrink)

Two old problems in probability theory involving the concept of randomness are considered. Data obtained with one of them--Bertrand's chord problem--demonstrate the equivocality of this term in the absence of a definition or explication of assumptions underlying its use. They also support two propositions about probabilistic thinking: (1) upon obtaining an answer to a question of probability, people tend to see it as the answer, overlooking tacit assumptions on which it may be based, and tend not to consider the possibility (...) of other assumptions from which different answers would follow; (2) perceptual balance--moderate uniformity of density of distribution--is a determinant of the degree to which a two-dimensional pattern is perceived as random. (shrink)

Two experiments were conducted with variants of Wason's (1966) selection task. The common focus was the effect of differences in the sizes of the sets represented by P and not-Q in assertions of the form _If P then Q_ (conditional) or _All P are Q_ (categorical). Results support the conclusion that such set size differences affect the strategies people adopt when asked to determine, efficiently, the truth or falsity of such assertions, but they do not entirely negate the tendency to (...) select the term represented by P (the antecedent of the conditional or the subject of the categorical) in preference to the term represented by not-Q (the complement of the consequent of the conditional or the complement of the predicate of the categorical). Several possible explanations of this perseverance are considered. Results also support the conclusion that people find it easier to assess categorical assertions than logically equivalent conditional assertions. (shrink)

Elqayam & Evans (E&E) argue that the major objective of research on human thinking should be the development of descriptive theories, and they challenge normativism the belief that people ought to conform to a normative standard” (target article, sect. 1, para. 10). I contend that although their argument for the importance of developing descriptive theories is compelling, normative theories are also important, not only for improving thinking but for investigating and understanding it as well.

Introduction This book is about reasoning. It is not a textbook in the conventional sense. Nor does it provide a prescription for how to reason effectively. ...

Participants attempted to solve a modified version of Wason's selection task. Variables were: sizes of the sets referenced by a specified assertion, form of the assertion, thematic content of the assertion, and the need for sampling or not. In Experiment 1, participants were given enough information to determine the truth or falsity of the specified assertion with certainty; in Experiment 2, they had to rely on sampling and could not determine the assertion's truth or falsity with certainty. Performance was better (...) in Experiment 1 than in Experiment 2, but in both cases much better than what is typically obtained with the conventional selection task. The results support the hypothesis that performance of the selection task is sensitive to the sizes of the sets involved, add credence to the conclusion that framing the task in a thematically meaningful way can facilitate performance, and demonstrate that facilitation does not require deontic reasoning or a well-known convention being involved. The relationship between expressed confidence and level of performance is consistent with other studies showing the former to be a good predictor of the latter. (shrink)

Time's mysteries seem to resist comprehension and what remains, once the familiar metaphors are stripped away, can stretch even the most profound philosopher. In Of Time and Lamentation, Raymond Tallis rises to this challenge and explores the nature and meaning of time and how best to understand it. The culmination of some twenty years of thinking, writing and wondering about (and within) time, it is a bold, original, and thought-provoking work. With characteristic fearlessness, Tallis seeks to reclaim time from (...) the jaws of physics. For most of us, time is composed of mornings, afternoons, and evenings and expressed in hurry, hope, longing, waiting, enduring, planning, joyful expectation, and grief. Thinking about it is to meditate on our own mortality. Yet, physics has little or nothing to say about this time, the time as it is lived. The story told by caesium clocks, quantum theory, and Lorentz coordinates, Tallis argues, needs to be supplemented by one of moss on rocks, tears on faces, and the long narratives of our human journey. Our temporal lives deserve a richer attention than is afforded by the equations of mathematical physics.The first part of the book, "Killing Time" is a formidable critique of the spatialized and mathematized account of time arising from physical science. Part 2, "Human Time" examines tensed time, the reality of time as it is lived: what we mean by "now", how we make sense of past and future events, and the idea of eternity. (shrink)

(1989). BLOOD IS THICKER THAN WATER: DON'T FORSAKE THE FAMILY JEWELS. Philosophical Papers: Vol. 18, No. 3, pp. 265-280. doi: 10.1080/05568648909506323.

Raymond Turner first provides a logical framework for specification and the design of specification languages, then uses this framework to introduce and study ...

An entertaining series of logic problems and puzzles of increasing difficulty, and all relating important mathematical and logical concepts, includes mind-benders, paradoxes, metapuzzles, number exercises, and a mathematical novel.

This work subjects the fundamental ideas of Derrida, Lacan, Barthes and their followers to an examination and demonstrates the baselessness of post-Saussurean claims about the relations between language, reality and self.

This work offers the first critical edition of Raymond Sebond's Theologie naturelle translated by Montaigne, with indexing of all the variants from the two editions of 1569 and 1581, and a transcription of the Latin text of the Theologia naturalis.

Professor Raymond Wacks breaks down the leading theories of justice and illustrates how present-day challenges, like terrorism and migration, affect our fundamental notions of fairness and democratic freedoms.

What is law? Does it have a purpose? What is its relationship with justice? Do we have a moral duty to obey the law? These sorts of questions lie at the heart of jurisprudence. Moreover, every substantive or 'black letter' branch of the law raises questions about its own meaning and function. The law of contract cannot be properly understood without an appreciation of the concepts of rights and duties. The law of tort is directly related to several economic theories (...) of compensation. The criminal law is inextricably linked to philosophies of punishment? Understanding Jurisprudence explores these problems and provides an engaging introduction to the central issues of legal theory. The book navigates the reader through legal philosophy's fundamental concepts, concerns, and controversies. An experienced teacher of jurisprudence and distinguished writer in the field, Professor Wacks adopts an approach that is easy to follow and understand without avoiding the complexities and subtleties of the subject. Students of law, politics, philosophy, and other social sciences will find this an ideal guide to the essential themes of contemporary jurisprudence. Online Resource Centre A free online resource accompanies the book and provides the following resources: Analysis of current controversies of a jurisprudential nature such as current legal and moral controversies and political debates An additional chapter providing guidance and advice on the study of jurisprudence An interactive glossary of key terms relating to legal theory Further reading, including links to full text journal articles Questions and answers Useful Web links to support learning. (shrink)

In Seeing Ourselves, philosopher and neuroscientist Raymond Tallis goes in search of what kind of beings we are, and where we might find meaning in our lives. Showcasing a remarkably detailed engagement with a huge range of disciplines, Tallis shows the unique nature of human consciousness.

Qu'entend-on par enchantement et désenchantement du monde? Quelles seraient les voies à suivre pour susciter un réenchantement du monde qui sera le fait de l’humain lui-même? La raison et la rationalité sont-elles les causes des maux de nos errements ou des outils pour les contrer? Suffira-t-il d’avoir « foi en la raison » pour surmonter les défis que l’humanité s’est elle-même imposés par négligence et irresponsabilité.

Tallis brings his familiar erudition and insight to this most intriguing and important philosophical question - the nature of our freedom - one that impacts most directly on our lives and takes us to the heart of what we are.

Negative words or integrated negations: Nothingness, the completely Other, Nothing, the Infinite, the Unknowable, the Subconscious all have a certain poetic overtone. But we must be careful of linguistic sleight-of-hand taken for an idea.

Malgré un titre qui peut paraître imposant et intimider, le lecteur trouvera dans ce livre le condensé, particulièrement clair et élégant, que Raymond Ruyer voulut donner de sa pensée au soir de sa vie, en un ultime effort de présentation et d'actualisation. L'ouvrage, entièrement achevé, était jusqu'à ce jour inédit, ce qui fait de sa publication un événement. La pensée de Ruyer a retenu l'attention de nombre des penseurs les plus importants de la seconde moitié du XXe siècle (comme (...) Merleau-Ponty, Canguilhem, Deleuze ou Lacan), qui n'hésitaient pas à la placer au plus haut. La publication du dernier manuscrit philosophique de Ruyer représente l'occasion de se familiariser avec sa pensée et de lui accorder enfin la place qu'elle mérite. L'objectif du philosophe de Nancy a consisté à construire un système métaphysique ajusté aux découvertes de la science contemporaine. S'il est bien question ici de "Dieu", ce n'est pas dans la perspective d'une révélation : le Dieu de Ruyer est un Dieu spéculatif, comme celui d'Aristote ou de Whitehead, et nous sommes loin des considérations sur "le savant et la foi". D'autre part, "l'embryogenèse du monde" n'est pas une rêverie incontrôlée sur quelque Oeuf primordial, mais une tentative argumentée de constituer un panpsychisme à la manière de Leibniz, selon ce que Ruyer appelle lui-même une "monadologie corrigée". (shrink)

Written by a creative master of mathematical logic, this introductory text combines stories of great philosophers, quotations, and riddles with the fundamentals of mathematical logic. Author Raymond Smullyan offers clear, incremental presentations of difficult logic concepts. He highlights each subject with inventive explanations and unique problems. Smullyan's accessible narrative provides memorable examples of concepts related to proofs, propositional logic and first-order logic, incompleteness theorems, and incompleteness proofs. Additional topics include undecidability, combinatoric logic, and recursion theory. Suitable for undergraduate and (...) graduate courses, this book will also amuse and enlighten mathematically minded readers. (shrink)

The primitive conception is that the future already exists like a terra incognita which one can dimly make out with or without the help of the gods. This idea is at the basis of fatalism and of belief in prophets, oracles and astrologers. This ancient concept was replaced in the nineteenth century by the vocabulary of scientific determinism which said that actual beings can only function. If one knew in detail their structures and their movements, one could calculate the results (...) of their functioning with perfect precision. (shrink)

Published now for the first time in English, Cybernetics and the Origin of Information is a deep exploration into information theory, cybernetics, and the philosophy of information. A true hidden gem in the history of continental thought, this text helps us determine and understand the contemporary technological moment.