Paradoxes, Miscellaneous

In his seminal paper ‘Reflection on Reflective Equilibrium’ Robert Cummins argued that if intuitions are to serve as reliable guides to philosophical truths then we should be able to check their reliability in particular cases. However, if we can check the reliability of intuitions then that means that we have an independent non-intuitive access to the domain that intuitions are supposed to disclose, which in effect makes intuitions obsolete. Overgaard, Gilbert and Burwood in their book ‘An Introduction to Metaphilosophy’ respond (...) to Cummins’ argument by claiming that at least logical intuitions do not demand independent validation because they provide cases of obvious noncontroversial truths. In this paper I discuss one aspect of the question concerning the reliability of philosophical intuitions. In particular, by relying on the so-called Curry’s paradox, I argue that even the intuitions concerning the validity of the basic logical rules, such as the modus ponens, can be problematized. In this respect, I argue that Cummins’ argument remains a viable challenge for those who think that intuitions provide special and undisputed authority in philosophical theorising. (shrink)

Paradoxes and their Resolutions is a ‘thematic compilation’ by Avi Sion. It collects in one volume the essays that he has written in the past (over a period of some 27 years) on this subject. It comprises expositions and resolutions of many (though not all) ancient and modern paradoxes, including: the Protagoras-Euathlus paradox (Athens, 5th Cent. BCE), the Liar paradox and the Sorites paradox (both attributed to Eubulides of Miletus, 4th Cent. BCE), Russell’s paradox (UK, 1901) and its derivatives the (...) Barber paradox and the Master Catalogue paradox (also by Russell), Grelling’s paradox (Germany, 1908), Hempel's paradox of confirmation (USA, 1940s), and Goodman’s paradox of prediction (USA, 1955). This volume also presents and comments on some of the antinomic discourse found in some Buddhist texts (namely, in Nagarjuna, India, 2nd Cent. CE; and in the Diamond Sutra, date unknown, but probably in an early century CE). (shrink)

According to Roy Sorensen, when one looks at the Moon, during a solar eclipse, what she sees is its inner part of the farther, reflective one, and not the always-facing-Earth side of our natural satellite. To make his point clearer, he put forward the famous example of a double eclipse involving the fictional planets Far and Near. From the observer’s vantage point, the two planets have the same apparent diameter and overlap. What the agent sees is a dark disk, but (...) believes that what she is seeing is Near, because Far is behind it. Sorensen claims that what she actually sees is planet Far and that the causal theory of perception explains why this is the case. Of course, this position stands against common sense. Sorensen shows that it counters Alvin Goldman’s renowned observation criteria too. Nonetheless, he maintains, since Near is causally idle and the agent does see something, the only possible conclusion is that she sees Far, pace Goldman – and common sense. In this paper, I try to demonstrate that Sorensen is wrong and that the correct solution to the eclipse riddle is that the observer sees Near. As a matter of fact, besides meeting common sense and Goldman’s observability criteria, Near can be legitimately be considered the object of a successful perceptual discrimination even in the light of the causal theory of perception. (shrink)

Aspetti filosofico-matematici dei celebri paradossi di Zenone di Elea.

This paper argues that if our talk of “premises” is not handled carefully, a classical language will contain sentences that are both true and false. This is so, even if a “premise” is defined in non-semantic terms, viz., as a sentence that is underived in the context of a proof. As a preliminary, I first explain that in classical logic, expressions must be seen as linguistic types rather than tokens. (Otherwise, ‘this very term = this very term’ is a false (...) instance of the Law of Identity.) Yet, if expressions are types, one can then derive a contradiction from the following premises: (1) Socrates is mortal; (2) (5) is not a premise, In the relevant proof, (5) is a derived sentence that is type-identical to ‘Socrates is mortal’. In such a proof, one can then show that sentence (1) is not a premise. A more sophisticated, proof-theoretic version of the paradox is also presented. (shrink)

I present a paradox concerning a person who desires to fail to achieve the goal that matters most to them. I recently encountered a similar paradox, but radical solipsism is a solution to it. This is not a solution to the paradox that I present.

Beall and Murzi :143–165, 2013) introduce an object-linguistic predicate for naïve validity, governed by intuitive principles that are inconsistent with the classical structural rules. As a consequence, they suggest that revisionary approaches to semantic paradox must be substructural. In response to Beall and Murzi, Field :1–19, 2017) has argued that naïve validity principles do not admit of a coherent reading and that, for this reason, a non-classical solution to the semantic paradoxes need not be substructural. The aim of this paper (...) is to respond to Field’s objections and to point to a coherent notion of validity which underwrites a coherent reading of Beall and Murzi’s principles: grounded validity. The notion, first introduced by Nicolai and Rossi, is a generalisation of Kripke’s notion of grounded truth, and yields an irreflexive logic. While we do not advocate the adoption of a substructural logic, we take the notion of naïve validity to be a legitimate semantic notion that points to genuine expressive limitations of fully structural revisionary approaches. (shrink)

In his famous book "Seeing Dark Things: The Philosophy of Shadows" (2008), Roy Sorensen put forward a ‘blocking theory of shadows’, a causal view on these entities according to which a shadow is an absence of light caused by blockage. This approach allows him to solve a quite famous riddle on shadows, ‘the Yale puzzle’, that was devised by Robert Fogelin in the late 1960s and that Sorensen presents in the form mentioned by Bas van Fraassen (1989). István Aranyosi has (...) recently criticized Sorensen’s solution to the Yale puzzle, on the grounds that it does not resist another version of the riddle, that Aranyosi calls ‘the Bilkent puzzle’. A new perspective on shadows, the ‘Material Exstitution View’, that allegedly permits to solve both puzzles, could be adopted as an alternative. In this paper I will show that Sorensen’s blockage theory can actually handle both the Yale and the Bilkent puzzle, plus another one that I put forward (‘the donut puzzle’), which instead is fatal to Aranyosi’s position. As Sorensen puts it, nothing aside from the original blockage of light is needed. (shrink)

ABSTRACTFregeans hold that predicates denote things, albeit things different in kind from what singular terms denote. This leads to a familiar problem: it seems impossible to say what any given predicate denotes. One strategy for avoiding this problem reduces the Fregean position to form of nominalism. I develop an alternative strategy that lets the Fregean hold on to the view that predicate denote things by reconceiving the nature of singular denotation and of Fregean objects.

This chapter briefly reviews the present state of judgment aggregation theory and tentatively suggests a future direction for that theory. In the review, we start by emphasizing the difference between the doctrinal paradox and the discursive dilemma, two idealized examples which classically serve to motivate the theory, and then proceed to reconstruct it as a brand of logical theory, unlike in some other interpretations, using a single impossibility theorem as a key to its technical development. In the prospective part, having (...) mentioned existing applications to social choice theory and computer science, which we do not discuss here, we consider a potential application to law and economics. This would be based on a deeper exploration of the doctrinal paradox and its relevance to the functioning of collegiate courts. On this topic, legal theorists have provided empirical observations and theoretical hints that judgment aggregation theorists would be in a position to clarify and further elaborate. As a general message, the chapter means to suggest that the future of judgment aggregation theory lies with its applications rather than its internal theoretical development. (shrink)

The Puzzle of the Hats is a betting arrangement which seems to show that a Dutch book can be made against a group of rational players with common priors who act in the common interest and have full trust in the other players’ rationality. But we show that appearances are misleading—no such Dutch book can be made. There are four morals. First, what can be learned from the puzzle is that there is a class of situations in which credences and (...) betting rates diverge. Second, there is an analogy between ways of dealing with situations of this kind and different policies for sequential choice. Third, there is an analogy with strategic voting, showing that the common interest is not always served by expressing how things seem to you in social decision-making. (shrink)

We show how removing faith-based beliefs in current philosophies of classical and constructive mathematics admits formal, evidence-based, definitions of constructive mathematics; of a constructively well-defined logic of a formal mathematical language; and of a constructively well-defined model of such a language. -/- We argue that, from an evidence-based perspective, classical approaches which follow Hilbert's formal definitions of quantification can be labelled `theistic'; whilst constructive approaches based on Brouwer's philosophy of Intuitionism can be labelled `atheistic'. -/- We then adopt what may (...) be labelled a finitary, evidence-based, `agnostic' perspective and argue that Brouwerian atheism is merely a restricted perspective within the finitary agnostic perspective, whilst Hilbertian theism contradicts the finitary agnostic perspective. -/- We then consider the argument that Tarski's classic definitions permit an intelligence---whether human or mechanistic---to admit finitary, evidence-based, definitions of the satisfaction and truth of the atomic formulas of the first-order Peano Arithmetic PA over the domain N of the natural numbers in two, hitherto unsuspected and essentially different, ways. -/- We show that the two definitions correspond to two distinctly different---not necessarily evidence-based but complementary---assignments of satisfaction and truth to the compound formulas of PA over N. -/- We further show that the PA axioms are true over N, and that the PA rules of inference preserve truth over N, under both the complementary interpretations; and conclude some unsuspected constructive consequences of such complementarity for the foundations of mathematics, logic, philosophy, and the physical sciences. -/- . (shrink)

This paper presents a case for the claim that the infamous miners paradox is not a paradox. This contention is based on some important observations about the nature of ignorance with respect to both disjunctions and conditional obligations and their modal features. The gist of the argument is that given the uncertainty about the location of the miners in the story and the nature of obligations, the apparent obligation to block either mine shaft is cancelled.

The object of this book is to present a radical novel conception of the ontological categories, their nature and epistemic importance. A conception that constitutes a challenge to the prevailing tenets, if not paradigms, of ontology today. The arguments and observations are given without addressing nor directly contesting the current theories on the subject. However, its author emphasises some of the main conclusions that entail from the new perspective, in particular regarding the role of philosophy among the sciences. Departing from (...) the novelty of considering distinctions to be the subject matter of thought and language -that is, of reference and meaning- it is observed that there are certain concepts, encompassed under the notion of “Being”, that are each “all” comprising categories. It is explained that these categories are conformed by certain ontological relations, which seem to stand for the structure of reality in-itself, and cannot be, in any manner, denied cognitive content nor objective existence in any possible world. Following this, it is argued that they constitute the primary premises of judgment and ultimate explanatory resources, and, thus, the fundaments of logic and mathematics. Moreover, language is shown to be structured according to them, and it is likewise explained that, as primary premises of all our judgments, they cannot be but determined a priori, standing for aspects of mind objective reality of a non-sensible nature, which are essential elements of cognition. It is shown, that it is they that enable to bridge the gap between the mind and the world, but set a limit to our possible knowledge of reality, which forces to presuppose the existence of higher or hyper-orders of reality. The importance of this work is, that from a naturalist stance, its observations and arguments constitute a strong case against established and well-rooted tenets in contemporary philosophy, while point to the need of focussing the field of the discipline to the study of the cognitive content of our innately determined a priori concepts. (shrink)

John Rawls’s difference principle says that we should change our economy if doing so is better for the worst-off group, on the condition that certain basic rights are secured. This paper presents a kind of case that challenges the principle. If we modify the principle to cope with the challenge, we open the way to a Sorites paradox.

It is often said that in a purely formal perspective, intuitionistic logic has no obvious advantage to deal with the liar-type paradoxes. In this paper, we will argue that the standard intuitionistic natural deduction systems are vulnerable to the liar-type paradoxes in the sense that the acceptance of the liar-type sentences results in inference to absurdity (⊥). The result shows that the restriction of the Double Negation Elimination (DNE) fails to block the inference to ⊥. It is, however, not the (...) problem of the intuitionistic approaches to the liar-type paradoxes but the lack of expressive power of the standard intuitionistic natural deduction system. We introduce a meta-level negation for a given system and a meta-level absurdity, ⋏, to the intuitionistic system. We shall show that in the system, the inference to ⊥ is not given without the assumption that the system is complete. Moreover, we consider the Double Meta-Level Negation Elimination rules (DMNE) which implicitly assume the completeness of the system. Then, the restriction of DMNE can rule out the inference to ⊥. (shrink)

Dialetheism is the view that there exists a true contradiction. This paper ventures to suggest that Priest’s argument for Dialetheism from Gödel’s theorem is unconvincing as the lesson of Gödel’s proof (or Rosser’s proof) is that any sufficiently strong theories of arithmetic cannot be both complete and consistent. In addition, a contradiction is derivable in Priest’s inconsistent and complete arithmetic. An alternative argument for Dialetheism is given by applying Gödel sentence to the inconsistent and complete theory of arithmetic. We argue, (...) however, that the alternative argument raises a circularity problem. In sum, Gödel’s and its related theorem merely show the relation between a complete and a consistent theory. A contradiction derived by the application of Gödel sentence has the value of true sentences, i.e. the both-value, only under the inconsistent models for arithmetic. Without having the assumption of inconsistency or completeness, a true contradiction is not derivable from the application of Gödel sentence. Hence, Gödel’s and its related theorem never can be a ground for Dialetheism. (shrink)

In this paper, I recreate a paradox from my earlier work (“Paradox with just self-reference”) albeit entirely within the language of arithmetic. (In lieu of self-referential expressions, Gödel numbering is used to generate the paradox.) This can suggest that Robinson arithmetic and its extensions are unsound; however, I claim instead that the metalanguage may be to blame, owing to arithmetization of syntax. If so, then the moral would be to restrict arithmetization in the metalanguage somehow, rather than distrust the arithmetical (...) theory in the object language. (shrink)

The perhaps most important criticism of the nontransitive approach to semantic paradoxes is that it cannot truthfully express exactly which metarules preserve validity. I argue that this criticism overlooks that the admissibility of metarules cannot be expressed in any logic that allows us to formulate validity-Curry sentences and that is formulated in a classical metalanguage. Hence, the criticism applies to all approaches that do their metatheory in classical logic. If we do the metatheory of nontransitive logics in a nontransitive logic, (...) however, there is no reason to think that the argument behind the criticism goes through. In general, asking a logic to express its own admissible metarules may not be a good idea. (shrink)

هل يمكن إذن أن أكون أنا لست أنا بانطباعات الزمان على جسدي وفكري؟ أليس لي جوهرٌ ثابتٌ تتبدل عليه الأعراض من حين إلى آخر، ومن ثم لا أفقد هويتي الحقيقية؟ لقد وُلدت منذ سنوات خلت، وتعلمت وعلمت أنني هو أنا، ويعلم المحيطون بي أنني هو أنا، بل يستطيع العلم المعاصر أن يُثبت أن لي تركيبًا جينيًا وراثيًا يميزني عن غيري، وأن لي بصمات أصابع وبصمة صوت لا تتطابق مع بصمات غيري، وسيحاسبني ربي يوم العرض عليه بوصفي شخصًا واحدًا هو أنا؛ (...) والشجرة التي تظلل باب منزلي هي ذات الشجرة التي أراها منذ سنوات، حقًا لقد تغيرت أعراضها، لكن جوهرها بالضرورة ثابت؛ وكوكب الزهرة المضيء مساءً وصباحًا هو ذات الكوكب الذي أراه كل يوم، قد تعتريه تغييرات عرضية، لكن جوهره قطعًا ثابت. ألسنا جميعًا نشترك في معرفة أن هذه الأشياء هي هي مهما تغيرت أعراضها؟. (shrink)

Some formulations of the surprise paradox involve a pair of unnecessary and controversial assumptions. After casting doubt on these assumptions, I propose a solution to the paradox.

Niko Kolodny and John MacFarlane claim that a situation involving some trapped miners involves a deontic paradox the resolution of which requires rejecting the logical law of modus ponens. I show that the appearance of paradox results from confusion and that the miners case supplies no cogent reason for impugning modus ponens.

The generality relativist has been accused of holding a self-defeating thesis. Kit Fine proposed a modal version of generality relativism that tries to resist this claim. We discuss his proposal and argue that one of its formulations is self-defeating.

Analysis of the surprise examination paradox supporting the idea that the students’ conclusion is not wrong but simply contradictory.

The Introduction to the collection of papers, _Reflexivity: A Source-book in Self-reference_. The Introduction studies the limits of our understanding that we carry unavoidably with us. We are perpetually confined within the horizons of our conceptual structure. When this structure grows or expands, the breadth of our comprehensions enlarges, but we are forever barred from the wished-for glimpse beyond its boundaries, no matter how hard we try, no matter how much credence we invest in the substance of our learning and (...) mist of speculation. (shrink)

This paper argues that, contrary to P. Eldridge-Smith, the so-called Pinocchio paradox affords no argument against ‘simply semantic dialetheism’.

Lewis Carroll’s 1895 paper, 'What the Tortoise Said to Achilles' is widely regarded as a classic text in the philosophy of logic. This special issue of 'The Carrollian' publishes five newly commissioned articles by experts in the field. The original paper is reproduced, together with contemporary correspondence relating to the paper and an extensive bibliography.

A consideration of the relationship between conscious self-aware systems and art. I introduce my art practice and demonstrate the connections language has to self-conscious reflexivity. The document of research can be considered part of a creative practice that also uses language as a material. The specialist use and subversive manipulation of information in science and art as practiced in the service of culture are discussed to show how this informed the creation of Access Restricted-Operational Reasons as a response to my (...) environment. (shrink)

We examine how Frege’s contrast between identity judgments of the forms “a=a” vs. “a=b” would fare in the special case where ‘a’ and ‘b’ are complex mental representations, and ‘a’ stands for an introspected ‘I’-thought. We first argue that the Fregean treatment of I-thoughts entails that they are what we call “one-shot thoughts”: they can only be thought once. This has the surprising consequence that no instance of the “a=a” form of judgment in this specific case comes out true, let (...) alone a priori true. This further reinforces Glezakos’s objections against the set-up of Frege’s puzzle, while also raising what we think is an acute problem for Fregeans, insofar as I-thought (and indexical thinking more generally), understood in their way, turns out to be incompatible with some basic features of rationality. (shrink)

A selective background -- Broadly classical approaches -- Paracompleteness -- More on paracomplete solutions -- Paraconsistent dialetheism.

The paradox that appears under Burali-Forti’s name in many textbooks of set theory is a clever piece of reasoning leading to an unproblematic theorem. The theorem asserts that the ordinals do not form a set. For such a set would be—absurdly—an ordinal greater than any ordinal in the set of all ordinals. In this article, we argue that the paradox of Burali-Forti is first and foremost a problem about concept formation by abstraction, not about sets. We contend, furthermore, that some (...) hundred years after its discovery the paradox is still without any fully satisfactory resolution. A survey of the current literature reveals one key assumption of the paradox that has gone unquestioned, namely the assumption that ordinals are objects. Taking the lead from Russell’s no class theory, we interpret talk of ordinals as an efficient way of conveying higher-order logical truths. The resulting theory of ordinals is formally adequate to standard intuitions about ordinals, expresses a conception of ordinal number capable of resolving Burali-Forti’s paradox, and offers a novel contribution to the longstanding program of reducing mathematics to higher-order logic. (shrink)

I consider a puzzling case presented by Jose Benardete, and by appeal to this case develop a paradox involving counterfactual conditionals. I then show that this paradox may be leveraged to argue for certain non-obvious claims concerning the logic of counterfactuals.

The principle of universal instantiation plays a pivotal role both in the derivation of intensional paradoxes such as Prior’s paradox and Kaplan’s paradox and the debate between necessitism and contingentism. We outline a distinctively free logical approach to the intensional paradoxes and note how the free logical outlook allows one to distinguish two different, though allied themes in higher-order necessitism. We examine the costs of this solution and compare it with the more familiar ramificationist approaches to higher-order logic. Our assessment (...) of both approaches is largely pessimistic, and we remain reluctantly inclined to take Prior’s and Kaplan’s derivations at face value. (shrink)

We develop an argument sketched by Luna (2011) based on the Pinocchio paradox, which was proposed by Eldridge-Smith and Eldridge- Smith (2010). We show that, upon plausible assumptions, the claim that mental states supervene on bodily states leads to the conclusion that some proposition is both paradoxical and not paradoxical. In order to show how the presence of paradoxes can be harnessed for philosophical argumentation, we present as well a couple of related arguments.

I criticise a paper by Peter Forrest in which he argues that a principle of unrestricted countable fusion has paradoxical consequences. I argue that the paradoxical consequences that he exhibits may be due to his Whiteheadean assumptions about the nature of spacetime rather than to the principle of unrestricted countable fusion.

I explain why research in non-applied, non-interdisciplinary, non-historical philosophy is worthwhile. The key move in the explanation is the realization that many philosophical problems can be put in the form of a set of highly plausible yet apparently jointly inconsistent claims regarding a fundamental notion.Export citation.

I consider cases in which risk or ignorance create barriers to our discovery of what we ought to do. I argue that neither expected utility theory, nor the maximin principle, nor a timid gambling temperament, is relevant to discovering what we ought to do in one-off or infrequently recurring types of decisions involving risk, or to decisions involving ignorance. I argue, contra Kolodny and MacFarlane, that the miners case does not require us to give up any classical logical principle in (...) order to avoid contradiction. I reject Graham’s claim that the appearance of contradiction depends upon a confusion between acting rightly and not being blameworthy. In the cases of risk and ignorance discussed, we cannot know what we ought to do; and any way of deciding what we shall do is objectively arbitrary even if it reflects our gambling temperament. Subjective probability and the subjective ought should be repudiated. (shrink)

Here, by introducing a version of “Unexpected hanging paradox” first we try to open a new way and a new explanation for paradoxes, similar to liar paradox. Also, we will show that we have a semantic situation which no syntactical logical system could support it. Finally, we propose a claim in Theory of Computation about the consistency of this Theory. One of the major claim is:Theory of Computation and Classical Logic leads us to a contradiction.

Disclosure of true but reputation-damaging information is generally legal. But threats to disclose true but reputation-damaging information unless payment is made are generally criminal. Many scholars think that this situation is paradoxical because it seems to involve illegality mysteriously arising out of legality, a criminal act mysteriously arising out of an independently legal threat to disclose conjoined with an independently legal demand for money. -/- But this formulation is not quite right. The real paradox raised by the different legal statuses (...) of blackmail threats to disclose and disclosure itself involves a contradiction between our strong intuition that blackmail threats should be criminal and some equally strong arguments, all of which depend on the fact that disclosure is legal, that blackmail threats should be legal. So an adequate solution to the real Blackmail Paradox requires us either to drop the intuition or to refute the pro-legalization arguments. -/- This Article will adopt the latter approach. It will explain why the six main arguments for legalizing blackmail threats all fail. In the course of refuting one of these arguments, it will also offer a novel positive justification for criminalizing blackmail threats: they should be criminal for the same reason that menacing, harassment, and stalking are criminal--namely, because they involve the reasonable likelihood, and usually the intent, of putting the victim into a state of especially great fear and anxiety. -/- Of course, one might object that disclosure itself is likely to have the same effect, if not malicious purpose. Yet, again, it is still legal. But this point shows only that we as a society value freedom of speech more than we value freedom from infliction of emotional injury. It does not show that we do not value freedom from infliction of emotional injury sufficiently to protect it when competing moral or institutional interests such as freedom of speech are not at stake. (shrink)

For each of the many goals of an agent it is true that the agent wants its realization. Given further very plausible assumptions, one can show that there is no good reason for an agent not to want the realization of all of his goals. However, it seems also true that reaching all of one’s goals would be extremely boring; most human beings would consider such a life not worth living. In this respect, leading a life is like playing some (...) game: A game loses its point if one always easily wins. Human agents not only pursue goals but they also have the second-order desire to lead the life of a goal-pursuer. More precisely, they want to be goal-pursuers such that many but not all of their goals are being realized. I argue here that they have a good reason not to want the realization of all of their goals. Now, all this constitutes an antinomy: Apparently, there are very plausible arguments both for affirming as well as denying that an agent has good reasons not to want the realization of his goals. This antinomy is similar to the preface-paradox about beliefs which has a convincing solution (due to Frank Ramsey). I argue, however, that there is no such solution in the case of goals. This leaves us with the question what a solution could look like. (shrink)

Substructural theories of truth are theories based on logics that do not include the full complement of usual structural rules. Existing substructural approaches fall into two main families: noncontractive approaches and nontransitive approaches. This paper provides a sketch of these families, and argues for two claims: first, that substructural theories are better-positioned than other theories to grapple with the truth-theoretic paradoxes, and second—more tentatively—that nontransitive approaches are in turn better-positioned than noncontractive approaches.

This article presents a paradox of inclusion, like Russell’s paradox but in a natural language.

Tarski's argumentative use of the liar paradox is well-known, but officially it is the Grelling paradox that has final pride of place in Tarski's argument, not the Liar at all. Tarski explicitly gives argumentation that adverts to the liar argument, but it is an alternative argument—one he only hints at and which adverts to the Grelling—which he says has the advantage of removing any empirical element. In this paper, we will examine how the Grelling might be used in place of (...) the Liar in Tarski's argument for his exact indefinability thesis, and assess in what way the difference might be significant. If successful, Tarski's use of the Grelling puts pressure on how Convention T can be justified. (shrink)