Can God create a stone too heavy for him to lift? Can time have a beginning? Which came first, the chicken or the egg? Riddles, paradoxes, conundrums--for millennia the human mind has found such knotty logical problems both perplexing and irresistible. Now Roy Sorensen offers the first narrative history of paradoxes, a fascinating and eye-opening account that extends from the ancient Greeks, through the Middle Ages, the Enlightenment, and into the twentieth century. When Augustine asked what God was doing (...) before He made the world, he was told: "Preparing hell for people who ask questions like that." A Brief History of the Paradox takes a close look at "questions like that" and the philosophers who have asked them, beginning with the folk riddles that inspired Anaximander to erect the first metaphysical system and ending with such thinkers as Lewis Carroll, Ludwig Wittgenstein, and W.V. Quine. Organized chronologically, the book is divided into twenty-four chapters, each of which pairs a philosopher with a major paradox, allowing for extended consideration and putting a human face on the strategies that have been taken toward these puzzles. Readers get to follow the minds of Zeno, Socrates, Aquinas, Ockham, Pascal, Kant, Hegel, and many other major philosophers deep inside the tangles of paradox, looking for, and sometimes finding, a way out. Filled with illuminating anecdotes and vividly written, A Brief History of the Paradox will appeal to anyone who finds trying to answer unanswerable questions a paradoxically pleasant endeavor. (shrink)

A Cabinet of Philosophical Curiosities is a collection of puzzles, paradoxes, riddles, and miscellaneous logic problems. Depending on taste, one can partake of a puzzle, a poem, a proof, or a pun.

Can merely thinking about an imaginary situation provide evidence for how the world actually is--or how it ought to be? In this lively book, Roy A. Sorensen addresses this question with an analysis of a wide variety of thought experiments ranging from aesthetics to zoology. Presenting the first general theory of thought experiment, he sets it within an evolutionary framework and integrates recent advances in experimental psychology and the history of science, with special emphasis on Ernst Mach and Thomas (...) Kuhn. Sorensen explores what thought experiments are, how they work, and what their virtues and vices are. In his view, philosophy differs from science in degree, but not in kind. For this reason, he claims, it is possible to understand philosophical thought experiments by concentrating on their resemblance to scientific relatives. Sorensen assesses the hazards of thought experiments and grants that there are interesting ways in which the method leads us astray, but attacks most scepticism about thought experiments as arbitrary. He maintains that they should be used--as they generally are--as part of a diversified portfolio of techniques, creating a network of cross-checks that make for impressive reliability. (shrink)

Sorensen here offers a unified solution to a large family of philosophical puzzles and paradoxes through a study of "blindspots": consistent propositions that cannot be rationally accepted by certain individuals even though they might by true.

Roy Sorenson offers a unique exploration of an ancient problem: vagueness. Did Buddha become a fat man in one second? Is there a tallest short giraffe? According to Sorenson's epistemicist approach, the answers are yes! Although vagueness abounds in the way the world is divided, Sorenson argues that the divisions are sharp; yet we often do not know where they are. Written in Sorenson'e usual inventive and amusing style, this book offers original insight on language and logic, the way world (...) is, and our understanding of it. (shrink)

Sorensen presents a general theory of thought experiments: what they are, how they work, what are their virtues and vices. On Sorensen's view, philosophy differs from science in degree, but not in kind. For this reason, he claims, it is possible to understand philosophical thought experiments by concentrating on their resemblance to scientific relatives. Lessons learned about scientific experimentation carry over to thought experiment, and vice versa. Sorensen also assesses the hazards and pseudo-hazards of thought experiments. Although (...) he grants that there are interesting ways in which the method leads us astray, he attacks most scepticism about thought experiments as arbitrary. They should be used, he says, as they generally are used--as part of a diversified portfolio of techniques. All of these devices are individually susceptible to abuse, fallacy, and error. Collectively, however, they provide a network of cross-checks that make for impressive reliability. (shrink)

In this book, Sorensen presents the first general theory of the thought experiment. He analyses a wide variety of thought experiments, ranging from aesthetics to zoology, and explores what thought experiments are, how they work, and what their positive and negative aspects are. Sorensen also sets his theory within an evolutionary framework and integrates recent advances in experimental psychology and the history of science.

The eclipse riddle -- Seeing surfaces -- The disappearing act -- Spinning shadows -- Berkeley's shadow -- Para-reflections -- Para-refractions : shadowgrams and the black drop -- Goethe's colored shadows -- Filtows -- Holes in the light -- Black and blue -- Seeing in black and white -- We see in the dark -- Hearing silence.

Drawing inspiration from the ethical pluralism of G. E. Moore's Principia Ethica, I contend that one empty world can be morally better than another. By ?empty? I mean that it is devoid of concrete entities (things that have a position in space or time). These worlds have no thickets or thimbles, no thinkers, no thoughts. Infinitely many of these worlds have laws of nature, abstract entities, and perhaps, space and time. These non-concrete differences are enough to make some of them (...) better than others. 1I thank Walter Sinnott-Armstrong, John Carroll, and Gideon Rosen for their comments and suggestions. (shrink)

Verisimilitude has the potential to deepen the understanding of mathematical progress, the principle of charity, and the psychology of regret. One obstacle is the widely held belief that two statements can vary in truthlikeness only if they vary in what they entail. This obstacle is removed with four types of counterexamples. The first concerns necessarily coextensive measurements that differ only with respect to their units (specifically length, area, and volume). The second class ofcounterexamples is composed of mathematical falsehoods. The third (...) class features inconsistent scientific theories. The fourth class of cases features statements that are instructive but meaningless. (shrink)

The aim of this paper is to show how thought experiments help us learn about laws. After providing examples of this kind of nomic illumination in the first section, I canvass explanations of our modal knowledge and opt for an evolutionary account. The basic application is that the laws of nature have led us to develop rough and ready intuitions of physical possibility which are then exploited by thought experimenters to reveal some of the very laws responsible for those intuitions. (...) The good news is that natural selection ensures a degree of reliability for the intuitions. The bad news is that the evolutionary account seems to limit the range of reliable thought experiment to highly practical and concrete contexts. In the fifth section, I provide reasons for thinking that we are not as slavishly limited as a pessimistic construal of natural selection suggests. Nevertheless, I promote the idea that biology is a promising source of predictions and diagnoses of thought experiment failures. (shrink)

The aim of this paper is to show how thought experiments help us learn about laws. After providing examples of this kind of nomic illumination in the first section, I canvass explanations of our modal knowledge and opt for an evolutionary account. The basic application is that the laws of nature have led us to develop rough and ready intuitions of physical possibility which are then exploited by thought experimenters to reveal some of the very laws responsible for those intuitions. (...) The good news is that natural selection ensures a degree of reliability for the intuitions. The bad news is that the evolutionary account seems to limit the range of reliable thought experiment to highly practical and concrete contexts. In the fifth section, I provide reasons for thinking that we are not as slavishly limited as a pessimistic construal of natural selection suggests. Nevertheless, I promote the idea that biology is a promising source of predictions and diagnoses of thought experiment failures. (shrink)

This is a defense and extension of Stephen Yablo's claim that self-reference is completely inessential to the liar paradox. An infinite sequence of sentences of the form 'None of these subsequent sentences are true' generates the same instability in assigning truth values. I argue Yablo's technique of substituting infinity for self-reference applies to all so-called 'self-referential' paradoxes. A representative sample is provided which includes counterparts of the preface paradox, Pseudo-Scotus's validity paradox, the Knower, and other enigmas of the genre. I (...) rebut objections that Yablo's paradox is not a genuine liar by constructing a sequence of liars that blend into Yablo's paradox. I rebut objections that Yablo's liar has hidden self-reference with a distinction between attributive and referential self-reference and appeals to Gregory Chaitin's algorithmic information theory. The paper concludes with comments on the mystique of self-reference. (shrink)

The argument proceeds by exploiting the gradually decreasing vagueness of a certain sequence of predicates. the vagueness of 'vague' is then used to show that the thesis that all vague predicates are incoherent is self-defeating. a second casualty is the view that the probems of vagueness can be avoided by restricting the scope of logic to nonvague predicates.

THE PURPOSE OF THIS ARTICLE IS TO SHOW HOW HUME’S SCEPTICISM ABOUT MIRACLES GENERATES "EPISTEMOLOGICAL" SCEPTICISM ABOUT TIME TRAVEL. SO THE PRIMARY QUESTION RAISED HERE IS "CAN ONE KNOW THAT TIME TRAVEL HAS OCCURED?" RATHER THAN "CAN TIME TRAVEL OCCUR?" I ARGUE THAT ATTEMPTS TO SHOW THE EXISTENCE OF TIME TRAVEL WOULD FACE THE SAME METHODOLOGICAL PROBLEMS AS THE ONES CONFRONTING ATTEMPTS TO DEMONSTRATE THE EXISTENCE OF PARANORMAL EVENTS. SINCE HUMEAN SCEPTICISM EXTENDS TO THE STUDY OF PARANORMAL EVENTS (PARAPSYCHOLOGY), HUMEANS (...) ARE COMMITTED TO SCEPTICISM ABOUT THE STUDY OF TIME TRAVEL ("PARAHISTORY"). (shrink)

A Brief History of the Paradox is the first narrative history of paradoxes. Sorenson draws us deep inside the tangles of riddles, paradoxes and conundrums by answering the questions which are seemingly unanswerable. Can God create a stone too heavy for him to lift? Can time have a beginning? Which came first, the chicken or the egg? Filled with illuminating anecdotes, A Brief History of the Paradox is vividly written and will appeal to anyone who finds trying to answer unanswerable (...) questions a paradoxically pleasant endeavour. (shrink)

(1984). Conditional blindspots and the knowledge squeeze: A solution to the prediction paradox. Australasian Journal of Philosophy: Vol. 62, No. 2, pp. 126-135.

Stepping into the other guy's shoes works best when you resemble him. After all, the procedure is to use yourself as a model: in goes hypothetical beliefs and desires, out comes hypothetical actions and revised beliefs and desires. If you are structurally analogous to the empathee, then accurate inputs generate accurate outputs-just as with any other simulation. The greater the degree of isomorphism, the more dependable and precise the results. This sensitivity to degrees of resemblance suggests that the method of (...) empathy works best for average people. The advantage of being a small but representative sample of the population will create a bootstrap effect. For as average people prosper, there will be more average descendants and so the degree of resemblance in subsequent generations will snowball. Each increment in like-mindedness further enhances the reliability and validity of mental simulation. With each circuit along the spiral, there is tighter and tighter bunching and hence further empowerment of empathy. The method is self-strengthening and eventually molds a population of hyper-similar individuals-which partly solves the problem of other minds. (shrink)

Stepping into the other guy’s shoes works best when you resemble him. After all, the procedure is to use yourself as a model: in goes hypothetical beliefs and desires, out comes hypothetical actions and revised beliefs and desires. If you are structurally analogous to the empathee, then accurate inputs generate accurate outputs---just as with any other simulation. The greater the degree of isomorphism, the more dependable and precise the results. This sensitivity to degrees of resemblance suggests that the method of (...) empathy works best for average people. The advantage of being a small but representative sample of the population will create a bootstrap effect. For as average people prosper, there will be more average descendants and so the degree of resemblance in subsequent generations will snowball. Each increment in like-mindedness further enhances the reliability and validity of mental simulation. With each circuit along the spiral, there is tighter and tighter bunching and hence further empowerment of empathy. The method is self-strengthening and eventually molds a population of hyper-similar individuals---which partly solves the problem of other minds. (shrink)

Stereotypically, computation involves intrinsic changes to the medium of representation: writing new symbols, erasing old symbols, turning gears, flipping switches, sliding abacus beads. Perspectival computation leaves the original inscriptions untouched. The problem solver obtains the output by merely alters his orientation toward the input. There is no rewriting or copying of the input inscriptions; the output inscriptions are numerically identical to the input inscriptions. This suggests a loophole through some of the computational limits apparently imposed by physics. There can be (...) symbol manipulation without inscription manipulation because symbols are complex objects that have manipulatable elements besides their inscriptions. Since a written symbol is an ordered pair of consisting of a shape and the reader's orientation to that inscription, the symbol can be changed by changing the orientation rather than inscription. Although there are the usual physical limits associated with reading the answer, the computation is itself instantaneous. This is true even when the sub-calculations are algorithmically complex, exponentially increasing or even infinite. (shrink)

My thesis is that ‘rational’ is an absolute concept like ‘flat’ and ‘clean’. Absolute concepts are best defined as absences. In the case of flatness, the absence of bumps, curves, and irregularities. In the case of cleanliness, the absence of dirt. Rationality, then, is the absence of irrationalities such as bias, circularity, dogmatism, and inconsistency.

Peter Slezak and William Boos have independently advanced a novel interpretation of Descartes's "cogito". The interpretation portrays the "cogito" as a diagonal deduction and emphasizes its resemblance to Godel's theorem and the Liar. I object that this approach is flawed by the fact that it assigns 'Buridan sentences' a legitimate role in Descartes's philosophy. The paradoxical nature of these sentences would have the peculiar result of undermining Descartes's "cogito" while enabling him to "disprove" God's existence.

Vagueness theorists tend to think that evolutionary theory dissolves the riddle "Which came first, the chicken or the egg?". After all, 'chicken' is vague. The idea is that Charles Darwin demonstrated that the chicken was preceded by borderline chickens and so it is simply indeterminate as to where the pre-chickens end and the chickens begin.