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.

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.

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.

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)

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)

An entertaining history of the idea of nothing - including absences, omissions, and shadows - from the Ancient Greeks through the 20th century How can nothing cause something? The absence of something might seem to indicate a null or a void, an emptiness as ineffectual as a shadow. In fact, 'nothing' is one of the most powerful ideas the human mind has ever conceived. This short and entertaining book by Roy Sorensen is a lively tour of the history and (...) philosophy of nothing, explaining how various thinkers throughout history have conceived and grappled with the mysterious power of absence -- and how these ideas about shadows, gaps, and holes have in turned played a very positive role in the development of some of humankind's most important ideas. Filled with Sorensen's characteristically entertaining mix of anecdotes, puzzles, curiosities, and philosophical speculation, the book is ordered chronologically, starting with the Taoists, the Buddhists, and the ancient Greeks, moving forward to the middle ages and the early modern period, then up to the existentialists and present day philosophy. The result is a diverting tour through the history of human thought as seen from a novel and unusual perspective. (shrink)

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)

Surprisingly, the fact that the speaker is lying is sometimes common knowledge between everyone involved. Strangely, we condemn these bald-faced lies more severely than disguised lies. The wrongness of lying springs from the intent to deceive – just the feature missing in the case of bald-faced lies. These puzzling lies arise systematically when assertions are forced. Intellectual duress helps to explain another type of non-deceptive false assertion : lying to yourself. In the end, I conclude that the apparent intensity of (...) our disapproval of non-deceptive lies is a rhetorical illusion. (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)

In ‘Epistemic Modals’ (2007), Seth Yalcin proposes Stalnaker-style semantics for epistemic possibility. He is inspired by John MacFarlane’s ingenious defence of relativism, in which claims of epistemic possibility are made rigidly from the perspective of the assessor’s actual stock of information (rather than from the speaker’s knowledge base or that of his audience or community). The innovations of MacFarlane and Yalcin independently reinforce the modal collapse espoused by Jaakko Hintikka in his 1962 epistemic logic (which relied on the implausible KK (...) principle and heavy idealizations). I respond to this new challenge with fresh objections to the underlying S4 equivalence: p p . I also propose counter-analyses of the intriguing data which Yalcin cites in support of his new semantics. A key collateral motivation for this defence of irredundant iterations is to ward off a threat to higher order vagueness. (shrink)

My thesis is that you can lie with ‘ P therefore Q ’ without P or Q being lies. For you can lie by virtue of not believing that P supports Q. My thesis is reconciled with the principle that all lies are assertions through H. P. Grice’s account of conventional implicatures. These semantic cousins of conversational implicatures are secondary assertions that clarify the speaker’s attitude toward his primary assertions. The meaning of ‘therefore’ commits the speaker to an entailment thesis (...) even though the speaker does not enter that commitment into the text. Insincere conventional implicatures are akin to insincerely asserted footnotes. An absence of lies in the text is compatible with the presence of lies in the meta-text. (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)

To understand lying, we naturally focus on small scale lies involving one speaker, one listener, one assertion. This methodology confers artificial plausibility upon the requirement that liars intend to deceive. For it excludes principal-agent conflicts that emerge from linguistic division of labor. When an employee lies for her boss, she need not inherit his motive to deceive. She displays loyalty even if her lie does not deceive. Focus on a single lie in isolation also blinds us to tactical deceptions such (...) as telling a lie which is intended to be caught to advance another lie. Many of these complexities arise from situations that approximate common knowledge without quite crystallizing into this uniform transparency. (shrink)

Kripshe treats ‘god’ as an empty natural kind term such as ‘unicorn’. She applies Saul Kripke's fresh views about empty natural kinds to ‘god’. Metaphysically, says Kripshe, there are no possible worlds in which there are gods. Gods could not have existed, given that they do not actually exist and never did. Epistemologically, godlessness is an a posteriori discovery. Kripshe dismisses the gods in the same breath that she dismisses mermaids. Semantically, the perspective Kripshe finds most perspicacious, no counterfactual situation (...) is properly describable as one in which there are gods. Perhaps it is not quite a necessary truth that there are no gods. According to Saul Kripke, failed natural kind terms are ill-defined. Incorporating ill-defined terms into declarative sentences yields only mock propositions. Just as the meteorologist has no professional interest in mock thunder, the logician has no professional interest in mock propositions. Kripshe disagrees with agnostics who assign a low probability to ‘There is at least one god’. The bearers of probabilities must be propositions. Despite this deference to science, Kripshe agrees with the a priori atheist that, necessarily, no future experience could constitute an encounter with a god. Divine revelation is impossible. Kripshe's a posteriori necessary atheism compares favorably to familiar forms of atheism and to non-cognitivists. It reveals interesting challenges to a coherent formulation of atheism. (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)

Islamic building codes require mosques to face Mecca. The further Islam spreads, the more apt are believers to fall into a quandary. X faces Y only when the front of X is closer to Y than any other side of X. So the front of the mosque should be oriented along a shortest path to Mecca. Which way is that? Does the path to Mecca tunnel through the earth? Or does the path follow the surface of the earth?

Immanuel Kant promised, ‘as Your Majesty's loyal subject’, to abstain from all public lectures about religion. All past commentators agree this phrase permitted Kant to return to the topic after the King died. But it is not part of the ‘at-issue content’. Consequently, ‘as Your Majesty's loyal subject’ is no more an escape clause than the corresponding phrase in ‘I guarantee, as your devoted fan, that these guitar strings will not break’. Just as the guarantee stands regardless of whether the (...) guarantor ceases to be your devoted fan, the compliance conditions of Kant's promise are not affected by Kant's ceasing to be the king's loyal subject. For good or ill, Kant made a lying promise to King Friedrich Wilhelm II in 1794. (shrink)

The vanishing point is a representational gap that organizes the visual field. Study of this singularity revolutionized art in the fifteenth century. Further reflection on the vanishing point invites the conjecture that the self is an absence. This paper opens with perceptual peculiarities of the vanishing point and closes with the metaphysics of personal identity.

Do not pass by my epitaph, Wayfarer, but when you have stopped, hear and learn, then depart. There is no boat, To carry you to Hades, No ferryman Charon, No judge Aeacus, No Dog Cerberus. All of us below have become bones and ashes. Truly, I have nothing more to tell you. So depart, wayfarer, Lest dead though I am I seem to you to be a teller of vain tales.

For most of his career, Kant accepts Augustine's requirement that lying requires an intention to deceive. However, he eventually converts to Aquinas, following him in rejecting this requirement in favor of Aristotle's teleological conception of lying. This change of view amounts to an improvement, for it makes room for the possibility of lying to an omniscient being—and such lies, we argue, are indeed possible. We accompany these historical and philosophical theses with a biographical thesis taking the form of the following (...) story. Kant believed that in his youth he had lied to God, largely because of his religious training. He adopted policies designed to help him resist the habit of lying to God. However, this program conflicted with his desire to lead a well‐rounded life as a public intellectual. This worldly ambition led him to forego the Quaker solution to the problem of lying to God: refuse to swear any oath to God, avoid set prayers and hymns, decline offers of intercession by clergy. Kant's worldly compromise served him well, but as he entered his twilight years, he came to worry that his only surviving argument for theism—the moral argument—might constitute a relapse into the vice of lying to God. (shrink)

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.

The vanishing point is a representational gap that organizes the visual field. Study of this singularity revolutionized art in the fifteenth century. Further reflection on the vanishing point invites the conjecture that the self is an absence. This paper opens with perceptual peculiarities of the vanishing point and closes with the metaphysics of personal identity.

Do we need light to see? I argue that the black experience of a man in a perfectly dark cave is a representation of an absence of light, not an absence of representation. There is certainly a difference between his perceptual knowledge and that of his blind companion. Only the sighted man can tell whether the cave is dark just by looking. But perhaps he is merely inferring darkness from his failure to see. To get an unambiguous answer, I switch (...) the focus from perceptual knowledge to non-epistemic seeing. My conclusion is that we see even in the limiting case of absolute darkness - regardless of whether we believe we are seeing. We see little of pratical interest. But in terms of basic information, we see about as much as we do when the lights are on. Depending on what has gone before and after, we may even see ordinary objects. (shrink)

You face two buttons. Pushing one will destroy Greensboro. Pushing the other will save it. There is no way for you to know which button saves and which destroys. What ought you to do? Answer: You ought to make the correct guess and push the button that saves Greensboro. Second question: Do you have an obligation to push the correct button?

If you read this abstract, then you will understand what my essay is about. Under what conditions would the preceding assertion be a lie? Traditional definitions of lying are always applied to straight declaratives such as ‘The dog ate my homework’. This one sided diet of examples leaves us unprepared for sentences in which conditional probability governs assertibility. The truth-value of conditionals does not play a significant role in the sincere assertion of conditionals. Lying is insincere assertion. So the connection (...) between lying and falsehood is broken when lying with conditionals. Drawing on Frank Jackson's account of indicative conditionals. I argue that it is possible to lie with true conditionals by virtue of their false conventional implicatures. False conversational implicatures only guarantee misleading assertions, not lies. Lying remains a semantic rather than a pragmatic affair. (shrink)

In ”Formal Problems about Knowledge,” Roy Sorensen examines epistemological issues that have logical aspects. He uses Fitch's proof for unknowables and the surprise test paradox to illustrate the hopes of the modal logicians who developed epistemic logic, and he considers the epistemology of proof with the help of the knower paradox. One solution to this paradox is that knowledge is not closed under deduction. Sorensen reviews the broader history of this maneuver along with the relevant alternatives model of (...) knowledge which assumes that ”know” is an absolute term like ”flat.” Sorensen argues that the difference between epistemic absolute terms and extensional absolute terms gives rise to an asymmetry that undermines recent claims that there is a structural parallel between the supervaluational and epistemicist theories of vagueness, and he suggests that we have overestimated the ability of logical demonstration to produce knowledge. (shrink)