We address the question of whether it is possible to operate a time machine by manipulating matter and energy so as to manufacture closed timelike curves. This question has received a great deal of attention in the physics literature, with attempts to prove no-go theorems based on classical general relativity and various hybrid theories serving as steps along the way towards quantum gravity. Despite the effort put into these no-go theorems, there is no widely accepted definition of a time machine. (...) We explain the conundrum that must be faced in providing a satisfactory definition and propose a resolution. Roughly, we require that all extensions of the time machine region contain closed timelike curves; the actions of the time machine operator are then sufficiently “potent” to guarantee that closed timelike curves appear. We then review no-go theorems based on classical general relativity, semi-classical quantum gravity, quantum field theory on curved spacetime, and Euclidean quantum gravity. Our verdict on the question of our title is that no result of sufficient generality to underwrite a confident “yes” has been proven. Our review of the no-go results does, however, highlight several foundational problems at the intersection of general relativity and quantum physics that lend substance to the search for an answer. (shrink)

No More Dying: The Conquest of Aging and the Extension of Human Life. By Joel Kurtzman and Phillip Gordon. Prolongevity. By Albert Rosenfeld.

Newton frequently characterized his methodology as distinctive and capable of achieving greater evidential support than that of his contemporaries, due to its mathematical character. Newton's pronouncements reflect a striking position regarding the role of mathematics in natural philosophy. We can give an initial characterization of his position by considering two questions central to seventeenth century debates about the applicability of mathematics. First, how are we to understand the distinctive universality and necessity of mathematical reasoning? One common way to preserve the (...) demonstrative character of mathematics was to restrict its domain, as far as possible, to pure abstractions. The subject matter of mathematics is then taken to be abstracted from the changeable natural world, consisting of quantity and magnitude themselves rather than the objects bearing quantifiable properties. Yet restricting the domain in this way leaves it difficult to see how mathematics relates to natural phenomena. How could the book of nature be written in a language of pure abstractions? Second, what is the proper role of mathematical reasoning in natural philosophy? Many followed Aristotle in consigning mathematics to a subordinate role. Mathematics could not fulfill the main aim of natural philosophy, namely to provide demonstrations reflecting the essences of things and nature's causal order. A related concern was also pressing for the mechanical philosophers: a merely mathematical demonstration fails to provide an intelligible mechanical explanation. The very title of Newton's masterpiece, Philosophiae Naturalis Principia Mathematica, would have been extremely perplexing: how could natural philosophy be based on mathematical principles? My aim is to articulate Newton's position regarding the mathematization of nature in response to these two concerns. (shrink)

A number of recent papers have criticized what they call the dynamical interpretation of evolutionary theory found in Elliott Sober’s The Nature of Selection. Sober argues that we can think of evolutionary theory as a theory of forces analogous to Newtonian mechanics. These critics argue that there are several important disanalogies between evolutionary and Newtonian forces: Unlike evolutionary forces, Newtonian forces can be considered in isolation, they have source laws, they compose causally in a straightforward way, and they are intermediate (...) causes in causal chains. Here we defend and extend the forces analogy by arguing that each of these criticisms is based on a misunderstanding of Newtonian forces. Our discussion also has the interesting consequence that natural selection turns out to be more similar to forces such as friction and elastic forces rather than the more canonical gravitation. (shrink)

We discuss the possibility to build and operate a time machine, a device that produces closed timelike curves. We specify the spacetime structure needed to implement a time machine and assess attempted no-go results against time machines in classical general relativity, semi-classical quantum gravity, quantum field theory on curved spacetime, and in Euclidean quantum gravity. Such no-go theorems for time machines would show that, under physically reasonable conditions, CTCs cannot develop in spacetimes initially free of these pathologies. Our review indicates (...) that an investigation of the prospects of achieving no-go results has not been entirely successful in establishing such generality. At the same time, the pursuit of chronology protection results has proved to be a fruitful way to probe the foundations of classical GTR and the interface between general relativity and quantum field theory. (shrink)

Cet article propose la première édition critique complète des Questions de Jean Buridan sur la Physiognomonie pseudo-aristotélicienne. L’introduction situe le texte dans la tradition physiognomonique médiévale, tout en indiquant les relations de la physiognomonie à la sémiologie, à l’astrologie et à la philosophie morale. L’édition se fonde sur trois manuscrits principaux, et un quatrième pour l’une des deux versions de la première question. Suit l’édition d’une version d’authenticité douteuse, qui recoupe en partie la version éditée, et de trois questions sur (...) la physiognomonie extraites d’un texte qui semble composite, formé de questions de Buridan ou d’esprit buridanien. (shrink)

Biological evolution provides a creative fount of complex and subtle adaptations, often surprising the scientists who discover them. However, because evolution is an algorithmic process that transcends the substrate in which it occurs, evolution’s creativity is not limited to nature. Indeed, many researchers in the field of digital evolution have observed their evolving algorithms and organisms subverting their intentions, exposing unrecognized bugs in their code, producing unexpected adaptations, or exhibiting outcomes uncannily convergent with ones in nature. Such stories routinely reveal (...) creativity by evolution in these digital worlds, but they rarely fit into the standard scientific narrative. Instead they are often treated as mere obstacles to be overcome, rather than results that warrant study in their own right. The stories themselves are traded among researchers through oral tradition, but that mode of information transmission is inefficient and prone to error and outright loss. Moreover, the fact that these stories tend to be shared only among practitioners means that many natural scientists do not realize how interesting and lifelike digital organisms are and how natural their evolution can be. To our knowledge, no collection of such anecdotes has been published before. This paper is the crowd-sourced product of researchers in the fields of artificial life and evolutionary computation who have provided first-hand accounts of such cases. It thus serves as a written, fact-checked collection of scientifically important and even entertaining stories. In doing so we also present here substantial evidence that the existence and importance of evolutionary surprises extends beyond the natural world, and may indeed be a universal property of all complex evolving systems. (shrink)

A volume of papers inspired by the work of George E. Smith on confirmation and evidence in advanced science—from Newton's gravitation theory to the physics of molecules.

This leading anthology contains essays and cases written by some of the most influential figures in legal philosophy, representing the major theoretical positions in the field. Its primary focus is to relate traditional themes of legal philosophy to the concerns of modern society in a way that invigorates the former and illuminates the latter. This classic text is distinguished by its clarity and accessibility, balance of topics, balance of positions on controversial questions, topical relevance, imaginative use of cases and stories, (...) and the inclusion of only lightly edited or untouched legal classics. This revision is distinguished by its inclusion of new material on law and economics, international law, distributive justice, religion and freedom of expression, feminist legal theory, and critical race theory, as well as a greater emphasis on concrete legal problems. (shrink)

Pierre Maquet1,2,6, Steven Laureys1,2, Philippe Peigneux1,2,3, Sonia Fuchs1, Christophe Petiau1, Christophe Phillips1,6, Joel Aerts1, Guy Del Fiore1, Christian Degueldre1, Thierry Meulemans3, André Luxen1, Georges Franck1,2, Martial Van Der Linden3, Carlyle Smith4 and Axel Cleeremans5.

We introduce a family of rules for adjusting one's credences in response to learning the credences of others. These rules have a number of desirable features. 1. They yield the posterior credences that would result from updating by standard Bayesian conditionalization on one's peers' reported credences if one's likelihood function takes a particular simple form. 2. In the simplest form, they are symmetric among the agents in the group. 3. They map neatly onto the familiar Condorcet voting results. 4. They (...) preserve shared agreement about independence in a wide range of cases. 5. They commute with conditionalization and with multiple peer updates. Importantly, these rules have a surprising property that we call synergy - peer testimony of credences can provide mutually supporting evidence raising an individual's credence higher than any peer's initial prior report. At first, this may seem to be a strike against them. We argue, however, that synergy is actually a desirable feature and the failure of other updating rules to yield synergy is a strike against them. (shrink)

The critical reception of Joel Chandler Harris's Uncle Remus Tales has often interpreted these animal fables as allegories of American slavery. Such an approach, however, risks what Steve Baker calls the ‘denial of the animal’, which displaces animal signifiers onto human signifieds. Through readings of ‘The Wonderful Tar-Baby Story’ and ‘How the Birds Talk’, I ask what it might mean to take seriously the numerous historical, political and philosophical questions posed by the animal ‘form’ that these characters assume, including (...) Heidegger's ontological differentiation between thing, animal and human, and Derrida's displacement of the conventional Cartesian distinction between animal reaction and human response. I argue that the racist equation of blacks with mimicry relies precisely on this dubious opposition. Remus's stories thus challenge our understandings of both race and language by showing how repetition and mimicry condition every ‘human’ response. (shrink)

In this paper, following an idea of Christophe Chalons. I propose a new kind of forcing axiom, the Maximality Principle, which asserts that any sentence varphi holding in some forcing extension $V^P$ and all subsequent extensions $V^{P\ast Q}$ holds already in V. It follows, in fact, that such sentences must also hold in all forcing extensions of V. In modal terms, therefore, the Maximality Principle is expressed by the scheme $(\lozenge \square \varphi) \Rightarrow \square \varphi$ , and is equivalent to (...) the modal theory S5. In this article. I prove that the Maximality Principle is relatively consistent with ZFC. A boldface version of the Maximality Principle, obtained by allowing real parameters to appear in φ, is equiconsistent with the scheme asserting that $V_\delta \prec V$ for an inaccessible cardinal δ, which in turn is equiconsistent with the scheme asserting that ORD is Mahlo. The strongest principle along these lines is $\square MP\!_{\!\!\!\!\!\!_{\!\!_\sim}}$ , which asserts that $MP\!_{\!\!\!\!\!\!_{\!\!_\sim}}$ holds in V and all forcing extensions. From this, it follows that $0^\#$ exists, that $x^\#$ exists for every set x, that projective truth is invariant by forcing, that Woodin cardinals are consistent and much more. Many open questions remain. (shrink)

Volume 20, Issue 1, February 2019, Page 99-102.

You and I are watching a spider crawl across the carpet. We are both aware of the spider, and aware that both are so aware. We are jointly attending to it. This collection of essays addresses a bewildering array of questions that arise regarding the notion of joint attention. How should joint attention be characterised in adults? In particular, how can we articulate the sense in which it is plausible to say that nothing is hidden from either participant in cases (...) of joint attention? What is the relationship between joint attention and the much discussed phenomenon of common, or mutual, knowledge? What account should be given of the development of the capacity for joint attention in children (and in non-human primates)? At what age is it correct to say that children are engaging in episodes of full blown joint attention? Relatedly, what is the relation between joint attention and pointing behaviour, gaze following and mutual affect regulation? Why is it that autistic children appear to exhibit a joint attention deficiency, and what might this tell us about autism, or about joint attention itself? Does the capacity for joint attention presuppose an understanding of the notion of attention, or more generally a subject of experience, and if so what is the relation between that understanding and the types of behaviour associated with joint attention? More generally, how does joint attention relate to our understanding of others? Finally, is the capacity for joint attention pivotal for the development of linguistic communication, or perhaps even a sense of objectivity—of the mind independence of the world? (shrink)

Hitchcock advances a diachronic Dutch Book argument (DDB) for a 1/3 answer to the Sleeping Beauty problem. Bradley and Leitgeb argue that Hitchcock’s DDB argument fails. We demonstrate the following: (a) Bradley and Leitgeb’s criticism of Hitchcock is unconvincing; (b) nonetheless, there are serious reasons to worry about the success of Hitchcock’s argument; (c) however, it is possible to construct a new DDB for 1/3 about which such worries cannot be raised.

Despite the recent increase of interest in the work of Merleau-Ponty there is still a persistent tendency to overlook the uniqueness of the philosophical position he advances in Phenomenology of Perception. In this article I present a reading of Merleau-Ponty’s account of the phenomenological reduction that explains how it is original. I do this by contrasting his presentation of the reduction with that of the early Husserl, highlighting how his emphasis on the phenomenology of the ‘perceived world’ leads him to (...) reject Husserl’s conception of phenomenology as a ‘philosophical science,’ and the Kantian language in which the this account is framed. I go on to critically discuss the interpretations of the reduction advanced by Stephen Priest and Joel Smith as examples of readings that fail to fully grasp Merleau-Ponty’s account of the ‘natural attitude’ as resting on the inherent objectivizing structure that is built into perception itself. The way that these authors misinterpret Merleau-Ponty helps to make maximally clear the profound philosophical significance that he places on the phenomenology of the ‘perceived world’. (shrink)

Un nouveau type de paternalisme s’est développé ces dix dernières années sous l’impulsion de travaux innovateurs de certains économistes comportementaux. Ce nouveau type de paternalisme, que j’appelle ici paternalisme comportemental, s’est popularisé grâce à la théorie du « coup de pouce » de Richard Thaler et Cass Sunstein et remet en question l’idée selon laquelle le paternalisme serait inacceptable dans nos sociétés. L’objet de cet article est d’évaluer sa légitimité morale sans, néanmoins, se limiter à son supposé libertarianisme. Les résultats (...) de mon investigation peuvent se résumer ainsi : bien que le paternalisme comportemental soit généralement reconnu pour son caractère libéral, il ne satisfait pas en fait les conditions de ce que Joel Feinberg nomme le « paternalisme mou ». Néanmoins, il possède des qualités morales sous-estimées par ses partisans. Il résiste d’abord très bien à la critique égalitariste d’Elizabeth Anderson. A la différence des formes traditionnelles de paternalisme, le paternalisme comportemental n’est pas dégradant et n’est pas ostracisant. Le paternalisme comportemental, enfin, peut se targuer d’être véritablement altruiste, à la condition, cependant, d’abandonner les hypothèses principales de Sunstein et Thaler. Classification JEL : A12, D64, I18, I31, K32. (shrink)

Aping apes: Edgar Allan Poe's "The murders in the Rue Morgue" and Richard Wright's Native son -- Slavery's bestiary: Joel Chandler Harris's Uncle Remus tales -- Autoimmunity and ante-racism: Philip Roth's The human stain -- Ashamed of shame: J.M. Coetzee's Disgrace.

Among early modern Christian kabbbalists such as Pico della Mirandola and Christian Knorr von Rosenroth, Kabbalah counts as part of philosophia perennis and esoteric Jewish philosophy. Bruckers differentiation between Kabbalah as esoteric Jewish philosophy and Maimonides as exoteric Jewish philosophy is taken up by Tiedemann and Hegel, and is well known to Schelling and Molitor. In opposition to this taxinomy among Christian philosophers, Jewish philosophers and scholars of »Wissenschaft des Judentums« like Salomon Munk, Manuel Joel, Hermann Cohen or Julius (...) Guttmann exclude Kabbalah from the canon of Jewish philosophy proper, exemplified by Yehuda Halevi or Maimonides. It is only after World War I that Gershom Scholem inaugurates the modern research of Kabbalah as »mysticism«, juxtaposed to philosophy and to the rationalistic traditions inJudaism. (shrink)

This book is concerned with the role of intuitions in the justification of philosophical theory. The author begins by demonstrating how contemporary philosophers, whether engaged in case-driven analysis or seeking reflective equilibrium, rely on intuitions as evidence for their theories. The author then provides an account of the nature of philosophical intuitions and distinguishes them from other psychological states. Finally, the author defends the use of intuitions as evidence by demonstrating that arguments for skepticism about their evidential value are either (...) self-defeating or guilty of arbitrary and unjustified partiality towards non-intuitive modes of knowledge. (shrink)

This book is about fundamental questions in normative ethics. It begins with the idea that we often respond to ethical theories according to how principled or pragmatic they are. It clarifies this contrast and then uses it to shed light on old debates in ethics, such as debates about the rival merits of consequentialist and deontological views. Using the idea that principled views seem most appealing in dilemmas of acquiescence, it goes on to develop a novel theory of pattern-based reasons. (...) These are reasons to play one’s part in some larger pattern of action because of the goodness or rightness of that pattern. Existing accounts of pattern-based reasons usually assume that such reasons can exist only in cooperative contexts. This book rejects that assumption, and claims instead that we can have pattern-based reasons even when the other agents involved in the pattern are wholly unwilling to cooperate. The result is a pluralist teleological structure for ethics, with similarities to some forms of Rule Consequentialism. Woodard claims that this structure achieves an attractive balance between the two virtues of being pragmatic and being principled. (shrink)

Isaac explores how influential thinkers in the mid-twentieth century understood the relations among science, knowledge, and the empirical study of human affairs. He places special emphasis on the practical, local manifestations of their complex theoretical ideas, particularly the institutional milieu of Harvard University.

Should the democratic exercise of authority that we take for granted in the realm of government be extended to the managerial sphere? Exploring this question, Christopher McMahon develops a theory of government and management as two components of an integrated system of social authority that is essentially political in nature. He then considers where in this structure democratic decision making is appropriate. McMahon examines the main varieties of authority: the authority of experts, authority grounded in a promise to obey, (...) and authority justified as facilitating mutually beneficial cooperation. He also discusses the phenomenon of managerial authority, the authority that guides nongovernmental organization, and argues that managerial authority is best regarded not as the authority of a principal over an agent, but rather as authority that facilitates mutually beneficial cooperation among employees with different moral aims. Viewed in this way, there is a presumption that managerial authority should be democratically exercised by employees. Originally published in 1994. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905. (shrink)

Georg Lukács wrote that "there is autonomy and 'autonomy.' The one is a moment of life itself, the elevation of its richness and contradictory unity; the other is a rigidification, a barren self-seclusion, a self-imposed banishment from the dynamic overall connection." Though Lukács' concern was with the conditions for the possibility of art, his distinction also serves as an apt description of the way that Hegel and Hegelians have contrasted their own interpretations of self-determination with that of Kant. But it (...) has always been difficult to see how elevation is possible without seclusion, or how rigidification can be avoided without making the boundaries of the self so malleable that its autonomy looks like a mere cover for the power of external forces. Yeomans explores Hegel's own attempts to grapple with this problem against the background of Kant's attempts, in his theory of virtue, to understand the way that morally autonomous agents can be robust individuals with qualitatively different projects, personal relations, and commitments that are nonetheless infused with a value that demands respect. In a reading that disentangles a number of different threads in Kant's approach, Yeomans shows how Hegel reweaves these threads around the central notions of talent and interest to produce a tapestry of self-determination. Yeomans argues that the result is a striking pluralism that identifies three qualitatively distinct forms of agency or accountability and sees each of these forms of agency as being embodied in different social groups in different ways. But there is nonetheless a dynamic unity to the forms because they can all be understood as practical attempts to solve the problem of autonomy, and each is thus worthy of respect even from the perspective of other solutions."Everyone recognizes the importance of Hegel's critique of Kantian morality as empty, but until now there has not been a fully worked out presentation of how Hegel's views in his discussion of Sittlichkeit actually provide the missing content. Yeomans has finally provided us with a reconstruction of Hegel's mature position that makes good on all the promissory notes that Hegel gives in his famous descriptions of his alternative to Kantian ethics. Yeomans offers a compelling account of Hegel's view of individuality, societal differentiation and its roots in Kantian and Fichtean moral theory. The book will be a major contribution to the scholarship on Hegel's practical philosophy." - Dean Moyar, Associate Professor of Philosophy, Johns Hopkins University -/- "Yeomans' book is a subtle, detailed and original explication of some key ideas having to do with how Hegel's general philosophy of action relates to his social and political philosophy. It is attentive to Hegel's texts, and it ties its discussions into all the relevant contemporary themes in philosophy. It is very ambitious in its attempt to make Hegel's theory into a real competitor to other views that are currently in wide play in the philosophical world. It will very likely become one of the key texts in the secondary literature on Hegel." - Terry Pinkard, University Professor of Philosophy, Georgetown University. (shrink)

Basing his view on the object relations theories of the "British School" of psychoanalysis, Christopher Bollas examines the human subject's memories of its earliest experiences (during infancy and childhood) of the object, whether it be mother, father, or self. He explains in well-written and non-technical language how the object can affect the child, or "cast in shadow," without the child being able to process this relation through mental representations of language.

Modern and contemporary transhumanism (distinct from posthumanism, see endnote i) is a philosophical movement that seeks the enhancement of the human body and mind though technological means.1 Its...

We analyze the expressivity, succinctness, and complexity of a family of languages based on weighted propositional formulas for the representation of utility functions. The central idea underlying this form of preference modeling is to associate numerical weights with goals specified in terms of propositional formulas, and to compute the utility value of an alternative as the sum of the weights of the goals it satisfies. We define a large number of representation languages based on this idea, each characterized by a (...) set of restrictions on the syntax of formulas and the range of weights. Our aims are threefold. First, for each language we try to identify the class of utility functions it can express. Second, when different languages can express the same class of utility functions, one may allow for a more succinct representation than another. Therefore, we analyze the relative succinctness of languages. Third, for each language we study the computational complexity of the problem of finding the most preferred alternative given a utility function expressed in that language. (shrink)

Christopher Ormell; Is the Uncertainty of Mathematics the Real Source of Its Intellectual Charm?, Journal of Philosophy of Education, Volume 27, Issue 1, 30 May.

"Modernity versus Postmodernity," Jü rgen Habermas. Critical Rejoinders: Fred Dallmayr. Christopher Norris. David C. Hoy. James Schmidt. Joel Whitebook. ThematicReformulations: James Bohman. Diana Coole. Jay M. Bernstein. David Ingram.

The "aphoristic form causes difficulty," Nietzsche argued in 1887, for "today this form is not taken seriously enough." Nietzsche's Aphoristic Challenge addresses this continued neglect by examining the role of the aphorism in Nietzsche's writings, the generic traditions in which he writes, the motivations behind his turn to the aphorism, and the reasons for his sustained interest in the form. This literary-philosophical study argues that while the aphorism is the paradigmatic form for Nietzsche's writing, its function shifts as his thought (...) evolves. His turn to the aphorism in Human, All Too Human arises not out of necessity, but from the new freedoms of expression enabled by his critiques of language and his emerging interest in natural science. Yet the model interpretation of an aphorism Nietzsche offers years later in On the Genealogy of Morals tells a different story, revealing more about how the mature Nietzsche wants his earlier works read than how they were actually written. This study argues nevertheless that consistencies emerge in Nietzsche's understanding of the aphorism, and these, perhaps counter-intuitively, are best understood in terms of excess. Recognizing the changes and consistencies in Nietzsche's aphoristic mode helps establish a context that enables the reader to navigate the aphorism books and better answer the challenges they pose. (shrink)

Prioritarianism itself is not committed to any particular claim about how moral importance decreases. It could decrease quickly or slowly, for example, and at a uniform or a variable rate. The defining feature of the view is just the claim that, somehow, moral importance decreases with the increasing advantage of the recipient.