Multi-agent scenarios, like Wigner’s friend and Frauchiger–Renner scenarios, can show contradictory results when a non-classical formalism must deal with the knowledge between agents. Such paradoxes are described with multi-modal logic as violations of the structure in classical logic. Even if knowledge is treated in a relational way with the concept of trust, contradictory results can still be found in multi-agent scenarios. Contextuality deals with global inconsistencies in empirical models defined on measurement scenarios even when there is local consistency. (...) In the present work, we take a step further to treat the scenarios in full relational language by using knowledge operators, thus showing that trust is equivalent to the Truth Axiom in these cases. A translation of measurement scenarios into multi-agent scenarios by using the topological semantics of multi-modal logic is constructed, demonstrating that logical contextuality can be understood as the violation of soundness by supposing mutual knowledge. To address the contradictions, assuming distributed knowledge is considered, which eliminates such violations but at the cost of lambda-dependence. We conclude by translating the main examples of multi-agent scenarios to their empirical model representation, contextuality is identified as the cause of their contradictory results. (shrink)

According to QBism, quantum states, unitary evolutions, and measurement operators are all understood as personal judgments of the agent using the formalism. Meanwhile, quantum measurement outcomes are understood as the personal experiences of the same agent. Wigner’s conundrum of the friend, in which two agents ostensibly have different accounts of whether or not there is a measurement outcome, thus poses no paradox for QBism. Indeed the resolution of Wigner’s original thought experiment was central to the development (...) of QBist thinking. The focus of this paper concerns two very instructive modifications to Wigner’s puzzle: One, a recent no-go theorem by Frauchiger and Renner, and the other a thought experiment by Baumann and Brukner. We show that the paradoxical features emphasized in these works disappear once both friend and Wigner are understood as agents on an equal footing with regard to their individual uses of quantum theory. Wigner’s action on his friend then becomes, from the friend’s perspective, an action the friend takes on Wigner. Our analysis rests on a kind of quantum Copernican principle: When two agents take actions on each other, each agent has a dual role as a physical system for the other agent. No user of quantum theory is more privileged than any other. In contrast to the sentiment of Wigner’s original paper, neither agent should be considered as in “suspended animation.” In this light, QBism brings an entirely new perspective to understanding Wigner’s friend thought experiments. (shrink)

The scientific literature on Wigner’s Friend extended paradox rapidly grew in the last years. A sign that Frauchiger and Renner (2018)’s argument caught an important point. Indeed, they conclude that either we must abandon the universal validity of quantum mechanics, or a certain kind of traditional objective knowledge is impossible. We investigate this contradiction through a logico-epistemic toolbox. We show that abandoning the transmissibility of knowledge, as proposed by many kinds of relational approaches to quantum mechanics, is (...) a heavy epistemological renouncement. Perhaps, it is better to bite the bullet and accept Frauchiger and Renner’s contradiction, until a new revolutionary solution will appear. (shrink)

In a recent no-go theorem [Bong et al., Nature Physics (2020)], we proved that the predictions of unitary quantum mechanics for an extended Wigner’s friend scenario are incompatible with any theory satisfying three metaphysical assumptions, the conjunction of which we call “Local Friendliness”: Absoluteness of Observed Events, Locality and No-Superdeterminism. In this paper (based on an invited talk for the QBism jubilee at the 2019 Växjö conference) I discuss the implications of this theorem for QBism, as seen from (...) the point of view of experimental metaphysics. I argue that the key distinction between QBism and realist interpretations of quantum mechanics is best understood in terms of their adherence to different theories of truth: the pragmatist versus the correspondence theories. I argue that a productive pathway to resolve the measurement problem within a pragmatist view involves taking seriously the perspective of quantum betting agents, even those in what I call a “Wigner bubble”. The notion of reality afforded by QBism, I propose, will correspond to the invariant elements of any theory that has pragmatic value to all rational agents—that is, the elements that are invariant upon changes of agent perspectives. The classical notion of ‘event’ is not among those invariants, even when those events are observed by some agent. Neither are quantum states. Nevertheless, I argue that far from solipsism, a personalist view of quantum states is an expression of its precise opposite: Copernicanism. (shrink)

The paper constructs a semi-formal language suited to the analysis of Wigner’s Friend scenarios: it represents an epistemic notion of rational beliefs and perspectives, to accommodate the insights of perspectival interpretations of quantum mechanics. The language is then used to analyze a paradox put forward by Frauchiger and Renner _(Nat Commun,_ 9(1):3711, 2018). Their argument is presented as a semi-formal derivation with specified rules of reasoning. These rules bear an affinity to some of the cherished tenets of (...) epistemology and we argue that they are valid (one universally, and the other in experimental contexts). Since our proof is a _reductio_, it leaves a choice which premises are responsible for a contradiction. Our first choice is a step that appears incorrect from the point of view of the universal unitary evolution as well as the view that every measurement induces a collapse of a measured system’s state. Our second choice, brought to view by the paper’s attention to perspectives and epistemology, points to a step reporting the transmission of beliefs (testimony) about measurement results. We argue that testimony is not licensed by quantum mechanical formalism; we discuss some recent attempts to save the cogency of testimony in the context of quantum measurements. (shrink)

Relational Quantum Mechanics is an interpretation of quantum mechanics proposed by Carlo Rovelli. Rovelli argues that, in the same spirit as Einstein’s theory of relativity, physical quantities can only have definite values relative to an observer. Relational Quantum Mechanics is hereby able to offer a principled explanation of the problem of nested measurement, also known as Wigner’s friend. Since quantum states are taken to be relative states that depend on both the system and the observer, there is no (...) inconsistency in the descriptions of the observers. Federico Laudisa has recently argued, however, that Rovelli’s description of Wigner’s friend is ambiguous, because it does not take into account the correlation between the observer and the quantum system. He argues that if this correlation is taken into account, the problem with Wigner’s friend disappears and, therefore, a relativization of quantum states is not necessary. I will show that Laudisa’s criticism is not justified. To the extent that the correlation can be accurately reflected, the problem of Wigner’s friend remains. An interpretation of quantum mechanics that provides a solution to it, like Relational Quantum Mechanics, is therefore a welcome one. (shrink)

In a recent paper, Zukowski and Markiewicz showed that Wigner’s Friend (and, by extension, Schrodinger’s Cat) can be eliminated as physical possibilities on purely logical grounds. I validate this result and demonstrate the source of the contradiction in a simple experiment in which a scientist S attempts to measure the position of object |O⟩ = |A⟩S +|B⟩S by using measuring device M chosen so that |A⟩M ≈ |A⟩S and |B⟩M ≈ |B⟩S. I assume that the measurement occurs by (...) quantum amplification without collapse, in which M can entangle with O in a way that remains reversible by S for some nonzero time period. This assumption implies that during this “reversible” time period, |A⟩M ̸= |A⟩S and |B⟩M ̸= |B⟩S – i.e., the macroscopic pointer state to which M evolves is uncorrelated to the position of O relative to S. When the scientist finally observes the measuring device, its macroscopic pointer state is uncorrelated to the object in position |A⟩S or |B⟩S, rendering the notion of “reversible measurement” a logical contradiction. (shrink)

A field-theoretic version of Wigner’s friend (1961) illustrates how the quantum measurement problem arises for field theory. Similarly, considering spacelike separate measurements of entangled fields by observers akin to Wigner’s friend shows the sense in which relativistic constraints make the measurement problem particularly difficult to resolve in the context of a relativistic field theory. We will consider proposals by Wigner (1961), Bloch (1967), Helwig and Kraus (1970), and Bell (1984) for resolving the measurement problem for quantum (...) field theory. We will conclude by considering the possibility of giving up rich dynamical explanation in the context of a many-maps formulation of relativistic quantum field theory. (shrink)

Recently there have emerged an assortment of theorems relating to the ‘absoluteness of emerged events,’ and these results have sometimes been used to argue that quantum mechanics may involve some kind of metaphysically radical non-absoluteness, such as relationalism or perspectivalism. However, in our view a close examination of these theorems fails to convincingly support such possibilities. In this paper we argue that the Wigner’s friend paradox, the theorem of Bong et al and the theorem of Lawrence et (...) al are all best understood as demonstrating that if quantum mechanics is universal, and if certain auxiliary assumptions hold, then the world inevitably includes various forms of ‘disaccord,’ but this need not be interpreted in a metaphysically radical way; meanwhile, the theorem of Ormrod and Barrett is best understood either as an argument for an interpretation allowing multiple outcomes per observer, such as the Everett approach, or as a proof that quantum mechanics cannot be universal in the sense relevant for this theorem. We also argue that these theorems taken together suggest interesting possibilities for a different kind of relational approach in which _interaction_ states are relativized whilst observed events are absolute, and we show that although something like ‘retrocausality’ might be needed to make such an approach work, this would be a very special kind of retrocausality which would evade a number of common objections against retrocausality. We conclude that the non-absoluteness theorems may have a significant role to play in helping converge towards an acceptable solution to the measurement problem. (shrink)

The possibility of algorithmic consciousness depends on the assumption that conscious states can be copied or repeated by sufficiently duplicating their underlying physical states, leading to a variety of paradoxes, including the problems of duplication, teleportation, simulation, self-location, the Boltzmann brain, and Wigner’s Friend. In an effort to further elucidate the physical nature of consciousness, I challenge these assumptions by analyzing the implications of special relativity on evolutions of identical copies of a mental state, particularly the divergence of (...) these evolutions due to quantum fluctuations. By assuming the supervenience of a conscious state on some sufficient underlying physical state, I show that the existence of two or more instances, whether spacelike or timelike, of the same conscious state leads to a logical contradiction, ultimately refuting the assumption that a conscious state can be physically reset to an earlier state or duplicated by any physical means. Several explanatory hypotheses and implications are addressed, particularly the relationships between consciousness, locality, physical irreversibility, and quantum no-cloning. (shrink)

The Frauchiger–Renner Paradox is an extension of paradoxes based on the “Problem of Measurement,” such as Schrödinger’s Cat and Wigner’s Friend. All these paradoxes stem from assuming that quantum theory has only unitary physical dynamics, and the attendant ambiguity about what counts as a ‘measurement’—i.e., the inability to account for the observation of determinate measurement outcomes from within the theory itself. This paper discusses a basic inconsistency arising in the FR scenario at a much earlier point than (...) the derived contradiction: namely, the inconsistency inherent in treating an improper mixture as a proper, epistemic mixture. This is an illegitimate procedure that is nevertheless endemic if quantum theory is assumed to be always unitary. In contrast, under a non-unitary account of quantum state reduction yielding determinate outcomes, the use of a proper mixture for measurement results becomes legitimate, and this entire class of paradoxes cannot be mounted. The conclusion is that the real lesson of the FR paradox is that it is the unitary-only assumption that needs to be critically reassessed. (shrink)

The internal paradoxes in the quantum measurement scheme related to violation of conservation laws, changes in entropy, absence of a dynamic description of collapse, Wigner's friend, as well as the paradox of violation of causality in the EPR experiment are shown to be partially circumvented in the measurement scheme of stochastic quantum mechanics.

The paradox of Wigner’s friend challenges the objectivity of quantum theory. A pragmatist interpretation can meet this challenge by judicious appeal to decoherence. Quantum theory provides situated agents with resources for predicting and explaining what happens in the physical world—not conscious observations of it. Even in bizarre Wigner’s friend scenarios, differently situated agents agree on the objective content of physical magnitude statements while, normally, quantum Darwinism permits agents equal observational access to their truth. Quantum theory (...) has nothing to say about conscious experiences. But it does prompt us to reexamine the significance of everyday claims about the physical world. (shrink)

An experiment by Proietti et al. purporting to instantiate the ‘Wigner’s Friend’ thought experiment is discussed. It is pointed out that the stated implications of the experiment regarding the alleged irreconcilability of facts attributed to different observers warrant critical review. In particular, violation of a Clauser–Horne–Shimony inequality by the experimental data actually shows that the attribution of measurement outcomes to the “Friends” is erroneous. An elementary but often overlooked result regarding improper mixtures is adduced in support of this (...) assessment, and a basic logical error in the analysis leading to the authors’ ontological claims that different observers are subject to irreconcilable ‘facts’ is identified. A counterexample is provided which refutes the popular notion that quantum theory leads to ‘relative facts’ that never manifest as empirical inconsistencies. It is further noted that under an assumption of unbroken unitarity, no measurement correlation can ever yield an outcome, since all systems remain in improper mixtures, and attributing a definite but unknown outcome contradicts their composite pure state. It is pointed out that there already exists a solution to this conundrum in the form of an alternative formulation of quantum theory, which accounts for the data showing that no outcomes occurred at the interior entangled photon level and also predicts that outcomes can and do occur at the exterior “super-observer” level in this type of experiment. (shrink)

It is generally agreed that decoherence theory is, if not a complete answer, at least a great step forward towards a solution of the quantum measurement problem. It is shown here however that in the cases in which a sentient being is explicitly assumed to take cognizance of the outcome the reasons we have for judging this way are not totally consistent, so that the question has to be considered anew. It is pointed out that the way the Broglie–Bohm model (...) solves the riddle suggests a possible clue, consisting in assuming that even very simple systems may have some sort of a proto-consciousness, but that their “internal states of consciousness” are not predictive. It is, next, easily shown that if we imagine the systems get larger, in virtue of decoherence their internal states of consciousness progressively gain in predictive value. So that, for macro-systems, they may be identified (in practice) with the predictive states of consciousness on which we ground our observational predictions. The possibilities of carrying over this idea to standard quantum mechanics are then investigated. Conditions of conceptual consistency are considered and found rather strict, and, finally, two solutions emerge, differing conceptually very much from one another but in both of which the, possibly non-predictive, generalized internal states of consciousness play a crucial role. (shrink)

The Quantum Measurement Problem is arguably one of the most debated issues in the philosophy of Quantum Mechanics, since it represents not only a technical difficulty for the standard formulation of the theory, but also a source of interpretational disputes concerning the meaning of the quantum postulates. Another conundrum intimately connected with the QMP is the Wigner friend paradox, a thought experiment underlining the incoherence between the two dynamical laws governing the behavior of quantum systems, i.e the Schrödinger (...) equation and the projection rule. Thus, every alternative interpretation aiming to be considered a sound formulation of QM must provide an explanation to these puzzles associated with quantum measurements. It is the aim of the present essay to discuss them in the context of Relational Quantum Mechanics. In fact, it is shown here how this interpretative framework dissolves the QMP. More precisely, two variants of this issue are considered: on the one hand, I focus on the “the problem of outcomes” contained in Maudlin (1995)—in which the projection postulate is not mentioned—on the other hand, I take into account Rovelli’s reformulation of this problem proposed in Rovelli (2022), where the tension between the Schrödinger equation and the stochastic nature of the collapse rule is explicitly considered. Moreover, the relational explanation to the Wigner’s friend paradox is reviewed, taking also into account some interesting objections contra Rovelli’s theory contained in Laudisa (2019). I contend that answering these critical remarks leads to an improvement of our understanding of RQM. Finally, a possible objection against the relational solution to the QMP is presented and addressed. (shrink)

Frauchiger and Renner have recently claimed to prove that “Single-world interpretations of quantum theory cannot be self-consistent”. This is contradicted by a construction due to Bell, inspired by Bohmian mechanics, which shows that any quantum system can be modelled in such a way that there is only one “world” at any time, but the predictions of quantum theory are reproduced. This Bell–Bohmian theory is applied to the experiment proposed by Frauchiger and Renner, and their argument is critically examined. It is (...) concluded that it is their version of “standard quantum theory”, incorporating state vector collapse upon measurement, that is not self-consistent. (shrink)

Von Neumann's theory of measurement in quantum mechanics is reinterpreted so that the experimental arrangement specifies the location of the “cut” by calling for the separate observation of the object and the measuring apparatus after the initial measurement interaction. The measurement ascertains which element of the mixture describing the final state of the apparatus is actually present. The relevance and feasibility of observing the final coherent state of the object plus apparatus is criticized and the paradoxes of “Schrödinger's cat” and (...) “Wigner's friend” are discussed. (shrink)

The Bayesian approach to quantum mechanics of Caves, Fuchs and Schack is presented. Its conjunction of realism about physics along with anti-realism about much of the structure of quantum theory is elaborated; and the position defended from common objections: that it is solipsist; that it is too instrumentalist; that it cannot deal with Wigner's friend scenarios. Three more substantive problems are raised: Can a reasonable ontology be found for the approach? Can it account for explanation in quantum theory? Are (...) subjective probabilities on their own adequate in the quantum domain? The first question is answered in the affirmative, drawing on elements from Nancy Cartwright's philosophy of science. The second two are not: it is argued that these present outstanding difficulties for the project. A quantum Bayesian version of Moore's paradox is developed to illustrate difficulties with the subjectivist account of pure state assignments. (shrink)

A drastic resolution of the quantum paradoxes is proposed, combining (I) von Neumann's postulate that collapse of the state vector is due to the act of observation, and (II) my reinterpretation of von Neumann's quantal irreversibility as an equivalence between wave retardation and entropy increase, both being “factlike” rather than “lawlike” (Mehlberg). This entails a coupling of the two de jure symmetries between (I) retarded and (II) advanced waves, and between Aristotle's information as (I) learning and (II) willing awareness. Symmetric (...) acceptance of cognizance as a source of retarted waves, and of will as a sink of advanced waves, is submitted as a central “paradox” of the Copernican or Einsteinian sort, out of which new light is shed upon previously known paradoxes, such as the EPR paradox, Schrödinger's cat, and Wigner's friend. Parapsychology is thus found to creep into the picture. (shrink)

The universality assumption (“U”) that quantum wave states only evolve by linear or unitary dynamics has led to a variety of paradoxes in the foundations of physics. U is not directly supported by empirical evidence but is rather an inference from data obtained from microscopic systems. The inference of U conflicts with empirical observations of macroscopic systems, giving rise to the century-old measurement problem and subjecting the inference of U to a higher standard of proof, the burden of which lies (...) with its proponents. This burden remains unmet because the intentional choice by scientists to perform interference experiments that only probe the microscopic realm disqualifies the resulting data from supporting an inference that wave states always evolve linearly in the macroscopic realm. Further, the nature of the physical world creates an asymptotic size limit above which interference experiments, and verification of U in the realm in which it causes the measurement problem, seem impossible for all practical purposes if nevertheless possible in principle. This apparent natural limit serves as evidence against an inference of U, providing a further hurdle to the proponent’s currently unmet burden of proof. The measurement problem should never have arisen because the inference of U is entirely unfounded, logically and empirically. (shrink)

The most well-known and controversial solution to the paradox of fiction is Kendall Walton’s, according to whom pity of (say) Anna Karenina is not genuine pity. Walton’s opponents argue that we can resolve the paradox of fiction while preserving the intuition that our response to Anna is ordinary, run-of-the-mill pity; and they claim that retaining this intuition explains more than Walton’s approach. In my view, the arguments of Walton’s opponents depend on idiosyncratic features of examples involving purely fictional (...) characters like Anna Karenina. What is really at issue is the fact that we respond emotionally to fiction in ways that are not explained by our beliefs, but instead by what we imagine. That this is the crux of the paradox of fiction becomes clear only when we consider fictions about real persons and events. And I contend that once we turn our attention to these cases, Walton’s theory proves significantly more explanatory than the opposition. (shrink)

It is widely taken for granted that fictions, including both literature and film,influence our attitudes toward real people, events, and situations. Philosopherswho defend claims about the cognitive value of fiction view this influence in apositive light, while others worry about the potential moral danger of fiction.Marketers hope that visual and aural references to their products in movies willhave an effect on people’s buying patterns. Psychologists study the persuasiveimpact of media. Educational books and films are created in the hopes of guidingchildren’s (...) and adult’s preferences toward socially acceptable norms.The influencesdiscussed by marketers, psychologists, educators, and philosophers tend to be bothcognitive and affective. It seems that we can be “emotionally persuaded”: ourpreferences can be changed, our feelings about particular people or events can beinfluenced, and so forth. (shrink)

The Schrödinger’s cat paradox has troubled physicists for many years and many ways to solve it has been provided so far. In this paper I will try to provide a different method of solving the Paradox with the help of logical machine and it will look like a hybrid of Wigner’s no-go theorem and the machine of Gödel in his Incompleteness Theorems. And due to the machine the paradox will not require any human intervention to measure (...) the state of the cat, whether it is alive or dead, while the measurement will be made by humans with regard to the statement given out by the machine. (shrink)

In today's societies relationships between near relatives and friends appear to be somewhat paradoxical. Some accounts present them as the social ideal, exalting the solidarity and altruism represented by proximal relationships. By contrast, others point to the social dangers in such relationships when they are conducted in the public sphere. In order to grasp the coexistence of these opposite views, this article attempts to place proximal relationships in the explanatory context of a gift economy, a concept with a long history (...) in anthropology and which has lately been the focus of interest of a significant group of social thinkers. (shrink)

The Schrodinger's Cat and Wigner's Friend thought experiments, which logically follow from the universality of quantum mechanics at all scales, have been repeatedly characterized as possible in principle, if perhaps difficult or impossible for all practical purposes. I show in this paper why these experiments, and interesting macroscopic superpositions in general, are actually impossible in principle. First, no macroscopic superposition can be created via the slow process of natural quantum packet dispersion because all macroscopic objects are inundated with decohering (...) interactions that constantly localize them. Second, the SC/WF thought experiments depend on von Neumann-style amplification to achieve quickly what quantum dispersion achieves slowly. Finally, I show why such amplification cannot produce a macroscopic quantum superposition of an object relative to an external observer, no matter how well isolated the object from the observer, because: the object and observer are already well correlated to each other; and reducing their correlations to allow the object to achieve a macroscopic superposition relative to the observer is equally impossible, in principle, as creating a macroscopic superposition via the process of natural quantum dispersion. (shrink)

We discuss the no-go theorem of Frauchiger and Renner based on an "extended Wigner's friend" thought experiment which is supposed to show that any single-world interpretation of quantum mechanics leads to inconsistent predictions if it is applicable on all scales. We show that no such inconsistency occurs if one considers a complete description of the physical situation. We then discuss implications of the thought experiment that have not been clearly addressed in the original paper, including a tension between relativity (...) and nonlocal effects predicted by quantum mechanics. Our discussion applies in particular to Bohmian mechanics. (shrink)

Although certain aspects of C.S. Lewis's work have been studied in great detail, others have been comparatively neglected. This collection of essays looks at Lewis's life and work, and those of his friends and associates, from many different angles, but all connected through a common theme of identity. Questions of identity are essential to the understanding of any writer. The ways authors perceive themselves and who they are, the communities they belong to by birth or choice, inevitably influence their work. (...) The way they present other people, real or fictional, are also rooted in their own conception of identity. In this volume, scholars from several countries examine gender and family roles; national, regional, racial and professional identities; membership of a particular church; ideological attachments and personal descriptions, either with regard to Lewis and those who knew him and influenced him, or in a study of their writings. Authors studied here include J.R.R. Tolkien, Dorothy L. Sayers, Charles Williams, George MacDonald and T.S. Eliot. (shrink)

Carl Schmitt's Concept of the Political advances an understanding of the political in which the political is assessed in terms of the autonomy of the friend-and-enemy distinction. This article questions the autonomous foundations of Schmitt's concept of the political. Ultimately, Schmitt's desire to establish the autonomous nature of the political, allowing the specifically political antithesis to achieve mastery over all other forms of discourse, is replete with paradox. Whilst Schmitt endeavours to establish the autonomy of the political—where the (...) political is free from interference from other domains—it is argued that his account of the political is highly dependent on the state. More critically, Schmitt's depiction of the political as autonomous is a strategic manoeuvre to establish the autonomy of the domain of the political vis-à-vis other conceptual domains. (shrink)

The paper first presents a short survey of ancient and modern logical, rhetorical and argumentative approaches (e.g. Aristotle, Quintilian, Quine, Anscombre and Ducrot) studying the properties of paradoxical utterances. This survey is followed by a tentative definition of paradoxes as seemingly contradictory utterances triggering conversational implicatures in the sense of Grice. A specific group of paradoxes, namely, persuasive paradoxes, is further characterized by the specific implicatures which they trigger: the implicatures of persuasive paradoxes serve the interest of the (political) speaker (...) because they either convey a sharp criticism of the political opponent(s) or praise the political activities of the speaker in a highly effective way.The second part of the paper takes a corpus of about 80 paradoxical utterances from Cicero's speeches to show how they are used 1. for a devastating criticism of Cicero's political enemies, 2. a milder form of criticism in the case of his friends, when their political activities have failed, 3. a praise of successful policies of Cicero and his political friends and 4. a defense of unsuccessful activities started by Cicero and his friends. (shrink)

The Wigner’s friend type of thought experiments manifest the conceptual challenge on how different observers can have consistent descriptions of a quantum measurement event. In this paper, we analyze the extended version of Wigner’s friend thought experiment in detail and show that the reasoning process from each agent that leads to the no-go theorem is inconsistent. The inconsistency is with respect to the requirement that an agent should make use of updated information instead of outdated information. (...) We then apply the relational formulation of quantum measurement to resolve the inconsistent descriptions from different agents. In relational formulation of quantum mechanics, a measurement is described relative to an observer. Synchronization of measurement result is a necessary requirement to achieve consistent descriptions of a quantum system from different observers. Thought experiments, including EPR, Wigner’s Friend and it extended version, confirm the necessity of relational formulation of quantum measurement when applying quantum mechanics to composite system with entangled but space-like separated subsystems. (shrink)

In this comment we critically review an argument against the existence of objective physical outcomes, recently proposed by Healey [1]. We show that his gedankenexperiment, based on a combination of “Wigner’s friend” scenarios and Bell’s inequalities, suffers from the main criticism, that the computed correlation functions entering the Bell’s inequality are in principle experimentally inaccessible, and hence the author’s claim is in principle not testable. We discuss perspectives for fixing that by adapting the proposed protocol and show that (...) this, however, makes Healey’s argument virtually equivalent to other previous, similar proposals that he explicitly criticises. (shrink)

I show in this paper why the universality of quantum mechanics at all scales, which implies the possibility of Schrodinger's Cat and Wigner's Friend thought experiments, cannot be experimentally confirmed, and why macroscopic superpositions in general cannot be observed or measured, even in principle. Through the relativity of quantum superposition and the transitivity of correlation, it is shown that from the perspective of an object that is in quantum superposition relative to a macroscopic measuring device and observer, the observer (...) is already sufficiently well correlated to the measuring device that once the object correlates to the measuring device, there is no time period in which the observer can perform an appropriate interference experiment to show that the measuring device is in a superposition. (shrink)

The knowability paradox is an instance of a remarkable reasoning pattern (actually, a pair of such patterns), in the course of which an occurrence of the possibility operator, the diamond, disappears. In the present paper, it is pointed out how the unwanted disappearance of the diamond may be escaped. The emphasis is not laid on a discussion of the contentious premise of the knowability paradox, namely that all truths are possibly known, but on how from this assumption the (...) conclusion is derived that all truths are, in fact, known. Nevertheless, the solution offered is in the spirit of the constructivist attitude usually maintained by defenders of the anti-realist premise. In order to avoid the paradoxical reasoning, a paraconsistent constructive relevant modal epistemic logic with strong negation is defined semantically. The system is axiomatized and shown to be complete. (shrink)

In this essay Amy Shuffelton considers Jean-Jacques Rousseau's suspicion of imagination, which is, paradoxically, offered in the context of an imaginative construction of a child's upbringing. First, Shuffelton articulates Rousseau's reasons for opposing children's development of imagination and their engagement in the sort of imaginative play that is nowadays considered a hallmark of early and middle childhood. Second, she weighs the merits of Rousseau's opposition, which runs against the consensus of contemporary social science research on childhood imaginative play. Ultimately, Shuffelton (...) argues that Rousseau's work offers an important cautionary note to enthusiasts of children's imaginative play, due to the potentially disruptive influence of consumer capitalism, though she also notes that imagination may play a more redemptive role than Rousseau granted it. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Fictions of Discourse: Reading Narrative TheoryCarol S. GouldFictions of Discourse: Reading Narrative Theory, by Patrick O’Neill; x & 188 pp. Toronto: University of Toronto Press, 1994, $35.00 paper.Patrick O’Neill serves up a rich stew of narratology, reader-reception theory, and a postmodern theory of truth. Many narratologists have taken the postmodern turn, while others have pursued a reception-theory route. Either path requires careful navigation, and the combined one even (...) more so. Classical narratology focuses on the textual structure with its network of various narratological relations. Reader-reception theory assigns to the reader a leading role in the creation of the text. O’Neill in various ways challenges or at least reformulates the notions of both text and reader, endorsing as he does a postmodern theory of truth which he terms the “Zeno Principle.” This principle is that “narrative discourse is always potentially subversive of the story it would seem to reconstruct” (p. 7). The Zeno Principle is a version of what he understands to be the Heisenberg Principle, namely that “discourse (including theoretical discourse) at least potentially subverts the story it sets out to narrate, and ultimately itself also” (p. 9). O’Neill contends that his narratological project will support the Zeno Principle. If successful, though, his endeavor will of course meet the usual self-destructive fate of such theories. But its self-annihilation seems not to discourage O’Neill, who finds all theories essentially “ludic.” O’Neill’s undertaking is ambitious; I shall focus on just a few of his moves.First of all, it is no surprise to hear that postmodernism is not new nor even that it has a classical pedigree. But it will probably astound—not to say sadden—the reader to see O’Neill locate its origins in the paradoxes of Zeno—the fifth-century Eleatic, the logician so well known for defending the epistemic primacy of reason, one of the uncontested intellectual progenitors of Plato, who remains the explicit target of Derridean fire. This is not simply a persnickety objection to O’Neill’s terminology, but a reflection on the broad implications he draws from his narratological investigations.Plato, working in the Eleatic (Zenoian) tradition, draws our attention to the perspectival nature of literature and would extend this to all empirical discourse. Any empirical narrative—history, biography, or literature—is in principle illusory because merely perspectival. Plato, true intellectual heir of Zeno, anticipates the narratological enterprise in this respect, while demonstrating [End Page 532] the exclusive epistemic integrity of logical thought. One finds this of course in his Republic, but nowhere are his narratological sympathies more evident than in the Symposium, with its many tiers of narration. He prefigures, then, the modern insight that all narrative is, in Wayne Booth’s terms, rhetoric and in narratological terms, focalized.If we grant with Zeno, Plato, and other friends of rationality that empirical discourse is perspectival or focalized, we can see that narrative must place us in some hypothetical vantage point: from another standpoint, the world looks different and assumes new contours and mood. Once we acknowledge that no one point of view is more privileged than another, our perceptions seem less stable. Lolita, for example, told from the viewpoint of the nymphet herself, would be a different story. Moreover, any narrative must be mediated by narrative perspective, and as O’Neill indicates, the narrative vantage point may not be that of the narrator or implied author. As he puts it, “Voice and vision... [may] derive from separate points of origin” (p. 84).In a sense, then, all empirical discourse is subversive. But does it follow that all theoretical discourse is therefore subversive? O’Neill scrutinizes fictional discourse, and helpfully so for us. But the perspectival nature of literary or empirical narrative hardly suffices to cast doubt on the notion of truth per se. The real Zeno Principle is the Platonic one that however arbitrarily empirical perspective might shift, rational intuition does not. If one wants to challenge that view, one must defend the Protagoras Principle, the true classical articulation of postmodernism. Aristotle, after all, wrestles with this in his Metaphysics rather than in his Poetics.O’Neill... (shrink)

Paradoxes are many things. Artificial intelligence views them as viruses of the brain, strange replicators that unexpectedly exploit design possibilities. For the child, they are intellectual cartwheels, an everyday delight. For mathematicians and logicians, they reveal skeletons in the closet of reason. For philosophers and dramatists, they capture the contradictions of experience. The historian of ideas sees that they come in successive waves, surging through Classical Greece, the Renaissance and the twentieth century. Professor Leiber's user-'friendly guide to paradoxes provides an (...) up-to-date survey of an ancient and perennial source of puzzlement. Book jacket. (shrink)

A recent no-go theorem (Frauchiger and Renner in Nat Commun 9(1):3711, 2018) establishes a contradiction from a specific application of quantum theory to a multi- agent setting. The proof of this theorem relies heavily on notions such as ‘knows’ or ‘is certain that’. This has stimulated an analysis of the theorem by Nurgalieva and del Rio (in: Selinger P, Chiribella G (eds) Proceedings of the 15th international conference on quantum physics and logic (QPL 2018). EPTCS 287, Open Publishing Association, Waterloo, (...) 2018), in which they claim that it shows the “[i]nadequacy of modal logic in quantum settings” (ibid.). In this paper, we will offer a significantly extended and refined reconstruction of the theorem in multi-agent modal logic. We will then show that a thorough reconstruction of the proof as given by Frauchiger and Renner requires the reflexivity of access relations (system T). However, a stronger theorem is possible that already follows in serial frames, and hence also holds in systems of doxastic logic (such as KD45). After proving this, we will discuss the general implications for different interpretations of quantum probabilities as well as several options for dealing with the result. (shrink)

The theories of pre-quantum physics are standardly seen as representing physical systems and their properties. Quantum mechanics in its standard form is a more problematic case: here, interpretational problems have led to doubts about the tenability of realist views. Thus, QBists and Quantum Pragmatists maintain that quantum mechanics should not be thought of as representing physical systems, but rather as an agent-centered tool for updating beliefs about such systems. It is part and parcel of such views that different agents may (...) have different beliefs and may assign different quantum states. What results is a collection of agent-centered perspectives rather than a unique representation of the physical world. In this paper we argue that the problems identified by QBism and Quantum Pragmatism do not necessitate abandoning the ideal of representing the physical world. We can avail ourselves of the same puzzle-solving strategies as employed by QBists and pragmatists by adopting a perspectival quantum realism. According to this perspectivalism objects may possess different, but equally objective properties with respect to different physically defined perspectives. We discuss two options for such a perspectivalism, a local and a nonlocal one, and apply them to Wigner’s friend and EPR scenarios. Finally, we connect quantum perspectivalism to the recently proposed philosophical position of fragmentalism. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Noël Carroll THE PARADOX OFJUNK FICTION Perhaps on your way to some academic conference, if you had no papers to grade, you stopped in die airport gift shop for something to read on the plane. You saw racks of novels authored by die likes of Mary Higgins Clark, Michael Crichton, John Grisham, Danielle Steele, Sidney Sheldon, Stephen King, Sue Grafton, Elmore Leonard, Sara Paretsky, Tom Clancy, and so (...) on. These are the kinds of novels that, when you lend them to friends, you don't care, unless you live in Bowling Green, Ohio, whether you ever get them back. They are mass, popular fictions. In another era, they would have been called pulp fictions. Following Thomas Roberts,1 I will call diem junk fictions, under which rubric I will also include things like Harlequin romances; sci-fi, horror, and mystery magazines; comic books; and broadcast narratives on either the radio or TV, as well as commercial movies. There are a number of interesting philosophical questions diat we may ask aboutjunk fiction. We could, for example, attempt to characterize its essential features. However, for the present, I will assume that the preceding examples are enough to provide you with a rough-andready notion of what I am calling junk fiction, and I will attempt to explore anotiier feature of the phenomenon, viz., what I call the paradox ofjunk fiction. Thejunk fictions that I have in mind are all narratives. Indeed, dieir story dimension is die most important thing about diem. Stephen King, for instance, makes diis point by saying that he is primarily a story teller rather than a writer. Junk fictions aspire to be page-turners—the blurb on the cover of Stillwatch by Mary Higgins Clark says that it is "designed to be read at breatiitaking speed"—and what motivates turning die page so quickly is our interest in what happens next. We do not dawdle Philosophy and Literature, © 1994, 18: 225-241 226Philosophy and Literature over Clark's diction as we might over Updike's nor do we savor die complexity of her sentence structure, as we do widi Virginia Woolfs. Radier, we read for story. Moreover, junk fictions are die sort of narratives that commentators are wont to call formulaic. That is, junk fictions generally belong to well-entrenched genres, which diemselves are typified by tiieir possession of an extremely limited repertoire of story-types. For example, as John Cawelti has pointed out, one such recurring Western narrative is diat of the recendy pacifist gunfighter, like Shane, who is forced by circumstances to take up his pistols again, widi altogedier devastating effect.2 Junk fictions tell diese generic stories again and again with minor variations. Sometimes diese variations may be quite clever and unexpected. Agatiia Christie was the master of this; she was able to use the conventions of the mystery genre in order to "hide" her murderers. In TheMurderofRogerAckroyd, she "secrets" the murderer in the personage of the narrator; in Ten Little Indians, die murderer is a "dead man"; while in Murder on the Orient Express, all the suspects did it. In each of these cases, Christie's brilliance hinges upon her playing (and preying) upon conventional expectations. Neverdieless, even diese surprising variations require a well-established background of narrative forms. That is, in order to appreciate diese variations, die reader must in some sense know die standard story already. And with junk fiction, it is generally fair to say that in some sense, the reader—or, at least, the reader who has read around in die genre before—knows in rough oudine how die story is likely to go. Readers and/or viewers of Jurassic Park surmised, once die dinosaur enclosures were described, diat in fairly short order die dinosaurs would trample them down and go on the rampage—after all we had already seen or read The Lost World, King Kong, and their progeny. So, junk fictions are formulaic. They rehearse certain narrative formats again and again. And, furthermore, in some very general sense, the audience already knows die story in question. But this knowledge on die part of die audience provokes a question, specifically, why if the reader, viewer or listener already... (shrink)

John Stuart Mill is the critical transitional figure between the classical liberalism of the 19th century, with its emphasis upon the creative power of free individuals unfettered by government or social interventions, and the welfare-state liberalism of the 20th century, with its combination of individual choice in matters of belief and lifestyle and the political redistribution of wealth. In On Liberty and The Subjection of Women , Mill offered a defense of self-sovereignty and voluntary association that appeared to extend explicitly (...) to the economic spheres. Both works are celebrations of the productive and moral enhancements of individual liberty. In The Principles of Political Economy , however, Mill's categorical distinction between “production” and “distribution” assigned the latter to the “expedient” discretion of the state, inviting, in theory, a democratic redistributionist state. Mill's posthumous Essays on Socialism reveal that he was no friend of socialism or Marxism, but that he welcomed a more active and interventionist state. One of individual liberty's most notable defenders, paradoxically, provided the theoretical underpinning of its current diminution. (shrink)

Patrick Aidan Heelan’s The Observable offers the reader a completely articulated development of his 1965 philosophy of quantum physics, Quantum Mechanics and Objectivity. In this previously unpublished study dating back more than a half a century, Heelan brings his background as both a physicist and a philosopher to his reflections on Werner Heisenberg’s physical philosophy. Including considerably broader connections to the contributions of Niels Bohr, Wolfgang Pauli, and Albert Einstein, this study also reflects Heelan’s experience in Eugene Wigner’s laboratory (...) at Princeton along with his reflections on working with Erwin Schrödinger dating from Heelan’s years at the Institute for Advanced Cosmology in Dublin. A contribution to continental philosophy of science, the phenomenological and hermeneutic resources applied in this book to the physical and ontological paradoxes of quantum physics, especially in connection with laboratory science and measurement, theory and model making, will enrich students of the history of science as well as those interested in different approaches to the historiography of science. University courses in the philosophy of physics will find this book indispensable as a resource and invaluable for courses in the history of science. (shrink)

A recent no-go theorem gives an extension of the Wigner’s Friend argument that purports to prove the “Quantum theory cannot consistently describe the use of itself.” The argument is complex and thought provoking, but fails in a straightforward way if one treats QM as a statistical theory in the most fundamental sense, i.e. if one applies the so-called ensemble interpretation. This explanation is given here at an undergraduate level, which can be edifying for experts and students alike. A (...) recent paper has already shown that the no-go theorem is incorrect with regard to the de Broglie Bohm theory and misguided in some of its general claims. This paper’s contribution is three fold. It shows how the extended Wigner’s Friend argument fails in the ensemble interpretation. It also makes more evident how natural a consistent statistical treatment of the wave function is. In this way, the refutation of the argument is useful for bringing out the core statistical nature of QM. It, in addition, manifests the unnecessary complications and problems introduced by the collapse mechanism that is part of the Copenhagen interpretation. The paper uses the straightforwardness of the ensemble interpretation to make the no-go argument and its refutation more accessible. (shrink)

There has been in recent years a huge surge of interest in the so-called extended Wigner’s friend scenario (EWFS). In short, a series of theorems (with some variation in detail) puts pressure on the ability of different agents in the scenario to account for each of the others’ measured outcomes: the outcomes cannot be assigned single well-defined values while also satisfying other reasonable physical assumptions. These theorems have been interpreted as showing that there can be no absolute, third-person, (...) ‘God’s eye’ description of our reality. The focus of this paper is the strongest of these no-go theorems, the ‘local friendliness’ theorem of Bong et al. (2020, _Nature Physics_, _16_, 1199–1205), which gives earnest consideration to the possibility of a measurement that unitarily reverses an entire lab system, including a conscious agent, thereby erasing the agent’s memory. The purpose of this paper is to begin the philosophical conversation regarding key questions concerning this process: Are the events in the lab merely ‘erased’, or do they in some sense not exist at all? What would it be like to be unitarily reversed? Should an agent care about any experiences they have inside the lab before they are reversed? This analysis employs a parallel case of memory erasure, to which this case can be contrasted, arising in the context of drug-induced amnesia as a result of administering anaesthesia during medical procedures (Carbonell, 2014, _Bioethics_, _28_(5), 245–254). I argue that the consequences of unitarily reversing an agent are much more dramatic than simply memory erasure—the set of events themselves, and the personal timeline of the agent, leave no record at all inside or outside the lab. I consider the ramifications of this for the picture of reality that arises from the EWFS. (shrink)

This chapter contains sections titled: Reference and Literary Language The Second Inheritance: Revealing the World through Metaphor and Paradox Initiation into the World: Appreciating the Adequacy of Words The Continuum between Philosophy and Literature Conclusion.

In quantum mechanics, the wavefunction predicts probabilities of possible measurement outcomes, but not which individual outcome is realised in each run of an experiment. This suggests that it describes an ensemble of states with different values of a hidden variable. Here, we analyse this idea with reference to currently known theorems and experiments. We argue that the ψ-ontic/epistemic distinction fails to properly identify ensemble interpretations and propose a more useful definition. We then show that all local ψ-ensemble interpretations which reproduce (...) quantum mechanics violate Statistical Independence. Theories with this property are commonly referred to as superdeterministic or retrocausal. Finally, we explain how this interpretation helps make sense of some otherwise puzzling phenomena in quantum mechanics, such as the delayed choice experiment, the Elitzur-Vaidman bomb detector, and the Extended Wigner's Friends Scenario. (shrink)

Rewards are reinforcement mechanisms that organizations use to shape desirable employee behaviors. However, rewards may also have unintended consequences, such as building expectations for receiving extra benefits and weakening employee barriers to unethical acts. This article investigates the dark side of the reward–behavior association, and exploring what is referred to as the reward–theft parity effect (RTPE). The authors hypothesize that receiving rewards induces a corresponding type of theft. In Study 1, survey results (n = 634) show initial support for the (...) RTPE between rewards and same‐category theft, and that perceptions of procedural justice attenuate this association. Study 2 involved a 2 (reward) × 2 (theft opportunity) between‐subjects experimental design (n = 300) and provides further support for the RTPE by revealing greater theft under a reward–theft parity condition than under a reward–theft disparity condition. Study 3 replicates these findings in a field experiment (n = 285) and finds that the RTPE is exacerbated when the reward–behavior task is perceived as unjust. Collectively, these findings provide new theoretical insights while also giving managers a more complete understanding of the dark side of behavioral reinforcement mechanisms. (shrink)