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)

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.

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)

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)

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)

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)

Charitable interpreters of David Hume set aside his sprinkles of piety. Better to read him as lying than as clumsily inconsistent. We argue that the attribution of lies can pay dividends in historical scholarship no matter how strongly the theorist condemns lying. Accordingly, we show that our approach works even with one of the strongest condemners of lying: Immanuel Kant. We argue that Kant lied in his scholarly work and even in the first Critique. And we defend the claim that (...) this lie attribution, strange as it may sound, amounts to a kind of scholarly charity. (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?

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.

Prize: One hundred dollars to the first person who identifies a picture of a logical impossibility. I may be willing to pay more for the painting itself. This finder’s fee is simply for pointing out the picture. Let me explain more precisely what I seek.

Sorites arguments employ an induction step such as ‘Small numbers have small successors’. People deduce that there must be an exception to the generalization but are reluctant to conclude that the generalization is false. My hypothesis is that the reluctance is due to the "Generic Overgeneralization Effect". Although the propounder of the sorites paradox intends the induction step to be a universal generalization, hearers assimilate universal generalizations to generic generalizations (for instance, ‘All birds fly’ tends to be remembered as ‘Birds (...) fly’). Most generic generalizations tolerate exceptions – especially when those exceptions are rare, abnormal, or difficult to imagine. Any counterexample to the induction step will have all of these features. (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)

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)

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

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)

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)

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)

The Pyrrhonian sceptic Favorinus of Arelata personified indeterminacy, cultivating his (or her) borderline status to undermine dogmatism. Inspired by the techniques of Favorinus, I show, by example, that ‘vague’ has borderline cases. These concrete steps lead to a more abstract argument that ‘vague’ has borderline borderline cases and borderline borderline borderline cases. My specimens are intended supplement earlier non-constructive proofs of the vagueness of ‘vague’.

But a winner must supply a nonevasive picture with no limit on potential detail--a purely imagistic depiction that does not rely on a mere description of an impossibility. There are logical minded philosophers from David Hume to Saul Kripke who think the prize cannot be won: What is conceivable is possible and whatever is depicted is thereby conceived, therefore, impossibilities cannot be depicted. Yet there is a rich aesthetics of inconsistency, best known through M. C. Escher. So I proceed with (...) the fine print for the competition. (shrink)

Todd’s quip absurdly implies he knew that 30 carats is the threshold for vulgarity. But most philosophers think stopping here misses the root of the joke. They think there is a more fundamental absurdity; that it is even possible for a single carat to make the difference between a vulgar ring and a non-vulgar ring. We epistemicists defend the possibility.

I can get away with it because no one is in a position to call me on it. Professor Robinson cannot consistently complain that (A) begs the question against his thesis that there is no such fallacy. He would discourage anyone from "helping" him by accusing me of committing the fallacy against him. With advocates like that, who needs adversaries? I. EMBEDDING PERSPECTIVES After all, Robinson has a viable reply to my argument. He should simply deny my premise. Later I (...) will show how (A) might rationally persuade Robinson. But my immediate goal is not to convert the skeptic about the existence of the fallacy but rather to use his extreme position to make a point about the nature of question-begging. Those who object that argument (A) begs the question against Robinson must do so on behalf of Robinson. This assistance requires that one launch the accusation from Robinson's perspective and with his dialectical interests at heart. (shrink)

Suppose you have an infinite past. If you had banked the spare dollar you have always had, then the interest would have made you rich by now. Your procrastination is inexcusable. But what should you have done? At any time at which you invest the dollar you would regret not investing it earlier. Satisficers can solve prospective puzzles involving infinite choice but cannot solve this retrospective puzzle about regret. A moral version of the puzzle suggests that there can be inevitable (...) moral failure. It does so without appeal to moral luck, moral dilemmas or original sin. (shrink)

This chapter focuses on armchair inquiry. Thought experiment has the feel of clairvoyance, thus eliciting awe in some and suspicion in others. But the wonder of thought experiment is just a special case of our vague puzzlement about how a question could be answered by merely thinking. There is no mystery when investigators look, measure, and manipulate. Their answers come from the news borne by observation and experiment. But if you just ponder, then the information you have leaving the armchair (...) is the same as the information you had when you sat down. It is argued that part of our wonder is based on a modal fallacy. The theories of armchair inquiry that promise answers to the legitimate portion of our wonder are surveyed. Finally, a cleansing model of rationality that sets the stage for a detailed analysis of how thought experiments work is developed. (shrink)