While Sigmund Freud and Maurice Merleau‐Ponty both acknowledge the role that spatiality plays in human life, neither pays any explicit attention to the intersections of race and space. It is Franz Fanon who uses psychoanalysis and phenomenology to provide an account of how the psychical and lived bodily existence of black people is racially constituted by a racist world. More precisely, as I argue in this paper, Fanon's work demonstrates how psychical and bodily spatiality cannot be adequately understood apart from (...) the environing space of the social world. For Fanon, body, psyche, and world mutually influence and constitute each other. In a raced and racist world, therefore, the lived bodily experience and the unconscious of human beings will be racially and racist‐ly constituted as well. This will show you how in psychoanalysis we take spatial ways of looking at things seriously. Sigmund Freud1 Sigmund Freud, “The Question of Lay Analysis,” in volume 20 of The Standard Edition of the Complete Psychological Works of Sigmund Freud, ed. and trans. James Strachey (London: The Hogarth Press, 1959), 195. Everything throws us back on to the organic relations between subject and space, to that gearing of the subject onto his world which is the origin of space. Maurice Merleau‐Ponty2 Maurice Merleau‐Ponty, Phenomenology of Perception, trans. Colin Smith (New York: Routledge, 1962), 251. Hence we are driven from the individual back to the social structure. If there is a [neurotic] taint, it lies not in the “soul” of the individual but rather in that of the environment. Franz Fanon3 Franz Fanon, Black Skin, White Mask, trans. Charles Lam Markmann (New York: Grove Press, 1967), 213. (shrink)

In our everyday social interactions, we try to make sense of what people are thinking, why they act as they do, and what they are likely to do next. This process is called mindreading. Mindreading, Shannon Spaulding argues in this book, is central to our ability to understand and interact with others. Philosophers and cognitive scientists have converged on the idea that mindreading involves theorizing about and simulating others’ mental states. She argues that this view of mindreading is limiting (...) and outdated. Most contemporary views of mindreading vastly underrepresent the diversity and complexity of mindreading. She articulates a new theory of mindreading that takes into account cutting edge philosophical and empirical research on in-group/out-group dynamics, social biases, and how our goals and the situational context influence how we interpret others’ behavior. -/- Spaulding's resulting theory of mindreading provides a more accurate, comprehensive, and perhaps pessimistic view of our abilities to understand others, with important epistemological and ethical implications. Deciding who is trustworthy, knowledgeable, and competent are epistemically and ethically fraught judgments: her new theory of mindreading sheds light on how these judgments are made and the conditions under which they are unreliable. -/- This book will be of great interest to students of philosophy of psychology, philosophy of mind, applied epistemology, cognitive science and moral psychology, as well as those interested in conceptual issues in psychology. (shrink)

A true Turing machine requires an infinitely long paper tape. Thus a TM can be housed in the infinite world of Newtonian spacetime, but not necessarily in our world, because our world-at least according to our best spacetime theory, general relativity-may be finite. All the same, one can argue for the "existence" of a TM on the basis that there is no such housing problem in some other relativistic worlds that are similar to our world. But curiously enough-and this is (...) the main point of this paper-some of these close worlds have a special spacetime structure that allows TMs to perform certain Turing unsolvable tasks. For example, in one kind of spacetime a TM can be used to solve first-order predicate logic and the halting problem. And in a more complicated spacetime, TMs can be used to decide arithmetic. These new computers serve to show that Church's thesis is a thoroughly contingent claim. Moreover, since these new computers share the fundamental properties of a TM in ordinary operation, a computability theory based on these non-Turing computers is no less worthy of investigation than orthodox computability theory. Some ideas about this new mathematical theory are given. (shrink)

Recently, philosophers and psychologists defending the embodied cognition research program have offered arguments against mindreading as a general model of our social understanding. The embodied cognition arguments are of two kinds: those that challenge the developmental picture of mindreading and those that challenge the alleged ubiquity of mindreading. Together, these two kinds of arguments, if successful, would present a serious challenge to the standard account of human social understanding. In this paper, I examine the strongest of these embodied cognition arguments (...) and argue that mindreading approaches can withstand the best of these arguments from embodied cognition. (shrink)

Mirror neurons are widely regarded as an important key to social cognition. Despite such wide agreement, there is very little consensus on how or why they are important. The goal of this paper is to clearly explicate the exact role mirror neurons play in social cognition. I aim to answer two questions about the relationship between mirroring and social cognition: What kind of social understanding is involved with mirroring? How is mirroring related to that understanding? I argue that philosophical and (...) empirical considerations lead us to accord a fairly minimal role for mirror neurons in social cognition. (shrink)

Direct Social Perception (DSP) is the idea that we can non-inferentially perceive others’ mental states. In this paper, I argue that the standard way of framing DSP leaves the debate at an impasse. I suggest two alternative interpretations of the idea that we see others’ mental states: others’ mental states are represented in the content of our perception, and we have basic perceptual beliefs about others’ mental states. I argue that the latter interpretation of DSP is more promising and examine (...) the kinds of mental states that plausibly could satisfy this version of DSP. (shrink)

New technologies from artificial intelligence to drones, and biomedical enhancement make the future of the human family increasingly hard to predict and protect. This book explores how the philosophical tradition of virtue ethics can help us to cultivate the moral wisdom we need to live wisely and well with emerging technologies.

The orthodox view of social cognition maintains that mentalizing is an important and pervasive element of our ordinary social interactions. The orthodoxy has come under scrutiny from various sources recently. Critics from the phenomenological tradition argue that phenomenological reflection on our social interactions tells against the orthodox view. Proponents of pluralistic folk psychology argue that our ordinary social interactions extend far beyond mentalizing. Both sorts of critics argue that emphasis in social cognition research ought to be on other elements of (...) our social practices. In this paper, I consider social explanations specifically and argue that social explanations are implicated in many of the social practices highlighted by critics of the orthodox view. (shrink)

Leading scholars explore how different forms of ignorance are produced and sustained, and the role they play in knowledge practices.

This paper argues in favor of more widespread and systematic applications of a virtue-based normative framework to questions about the ethical impact of information technologies, and social networking technologies in particular. The first stage of the argument identifies several distinctive features of virtue ethics that make it uniquely suited to the domain of IT ethics, while remaining complementary to other normative approaches. I also note its potential to reconcile a number of significant methodological conflicts and debates in the existing literature, (...) including tensions between phenomenological and constructivist perspectives. Finally, I claim that a virtue-based perspective is needed to correct for a strong utilitarian bias in the research methodologies of existing empirical studies on the social and ethical impact of IT. The second part of the paper offers an abbreviated demonstration of the merits of virtue ethics by showing how it might usefully illuminate the moral dimension of emerging social networking technologies. I focus here on the potential impact of such technologies on three virtues typically honed in communicative practices: patience, honesty and empathy. (shrink)

Recently, there has been a resurgence of interest in theories of mindreading. New discoveries in neuroscience have revitalized the languishing debate. The discovery of so-called mirror neurons has revived interest particularly in the Simulation Theory (ST) of mindreading. Both ST proponents and theorists studying mirror neurons have argued that mirror neurons are strong evidence in favor of ST over Theory Theory (TT). In this paper I argue against the prevailing view that mirror neurons are evidence for the ST of mindreading. (...) My view is that on an appropriate construal of their function, mirror neurons do not operate like simulation theorists claim. In fact, mirror neurons are more appropriately understood as one element in an information-rich mindreading process. As such, mirror neurons fit in better with some sort of TT account of mindreading. I offer a positive account, the Model TT, which better explains the role of mirror neurons in social cognition. (shrink)

Imagination seems to play an epistemic role in philosophical and scientific thought experiments, mindreading, and ordinary practical deliberations insofar as it generates new knowledge of contingent facts about the world. However, it also seems that imagination is limited to creative generation of ideas. Sometimes we imagine fanciful ideas that depart freely from reality. The conjunction of these claims is what I call the puzzle of knowledge through imagination. This chapter aims to resolve this puzzle. I argue that imagination has an (...) epistemic role to play, but it is limited to the context of discovery. Imagination generates ideas, but other cognitive capacities must be employed to evaluate these ideas in order for them to count as knowledge. Consideration of the Simulation Theory's so-called "threat of collapse” provides further evidence that imagination does not, on its own, yield new knowledge of contingent facts, and it suggests a way to supplement imagination in order to get such knowledge. (shrink)

According to Shannon Sullivan, thinking about the body as being in transaction with its social, political, cultural, and physical surroundings is not a new idea.

"I found this a fascinating book: wide-ranging, readable." —Alison Jaggar Bell shows how the flesh-and-blood female body engaged in sexual interaction for payment has no inherent meaning and is signified differently in different cultures ...

The widespread and growing use of new social media, especially social networking sites such as Facebook and Twitter, invites sustained ethical reflection on emerging forms of online friendship. Social scientists and psychologists are gathering a wealth of empirical data on these trends, yet philosophical analysis of their ethical implications remains comparatively impoverished. In particular, there have been few attempts to explore how traditional ethical theories might be brought to bear upon these developments, or what insights they might offer, if any. (...) In attempting to address this lacuna in applied ethical research, this paper investigates the ethical significance of online friendship by means of an Aristotelian theory of the good life, which holds that human flourishing is chiefly realized through ‘complete’ friendships of virtue. Here, four key dimensions of ‘virtue friendship’ are examined in relation to online social media : reciprocity, empathy, self-knowledge and the shared life. Online social media support and strengthen friendship in ways that mirror these four dimensions, particularly when used to supplement rather than substitute for face-to-face interactions. However, deeper reflection on the meaning of the shared life for Aristotle raises important and troubling questions about the capacity of online social media to support complete friendships of virtue in the contemporary world, along with significant concerns about the enduring relevance of this Aristotelian ideal for the good life in the 21st century. (shrink)

Most people think of themselves as pretty good at understanding others’ beliefs, desires, emotions, and intentions. Accurate mindreading is an impressive cognitive feat, and for this reason the philosophical literature on mindreading has focused exclusively on explaining such successes. However, as it turns out, we regularly make mindreading mistakes. Understanding when and how mind misreading occurs is crucial for a complete account of mindreading. In this paper, I examine the conditions under which mind misreading occurs. I argue that these patterns (...) of mind misreading shed light on the limits of mindreading, reveal new perspectives on how mindreading works, and have implications for social epistemology. (shrink)

Taking an interdisciplinary approach, this book traces the development of entropic themes, capturing phenomena ranging from chaos, disorder, homogenization, slackening, disspation, and ultimately death.

Traditional theories of mindreading tend to focus exclusively on attributing beliefs and desires to other agents. The literature emphasizes belief attribution in particular, with numerous debates over when children develop the concept of belief, how neurotypical adult humans attribute beliefs to others, whether non-human animals have the concept of belief, etc. I describe a growing school of thought that the heavy focus on belief leaves traditional theories of mindreading unable to account for the complexity, diversity, and messiness of ordinary social (...) interactions. I present a few broader, more comprehensive conceptions of mindreading that take into account how stereotypes, character trait inferences, social biases, and more influence how we understand and interact with others. These broader conceptions of mindreading promise to be more empirically adequate and have fruitful application to various debates in philosophy and cognitive science. (shrink)

Theory of mind, also known as mindreading, refers to our ability to attribute mental states to agents in order to make sense of and interact with other agents. Recently, theorists in this literature have advanced a broad conception of mindreading. In particular, psychologists and philosophers have examined how we attribute knowledge, intention, mentalistically-loaded stereotypes, and personality traits to others. Moreover, the diversity of our goals in a social interaction – precision, efficiency, self/in-group protection – generates diversity in the mindreading processes (...) we employ. Finally, the products of mindreading are varied, as well. We produce different sorts of mindreading explanations depending on our epistemic goals and the situational context. In this article, I piece together these different strands of research to present a broad conception of mindreading that is complex, messy, and interesting. (shrink)

We have various strategies available to us for understanding another person’s state of mind. Cognitive empathy may be achieved by mental simulation, i.e. by imagining yourself in another’s situation and figuring out what you would think and feel in that situation. Alternatively, you could consider all the relevant information about the person’s situation and folk psychology and draw a sophisticated inference to the best explanation of that person’s perspective. In this chapter, I examine the conditions under which we are likely (...) to use these two familiar strategies for cognitive empathy and when they are likely to be effective. In addition, I discuss a third underexplored pattern of reasoning in understanding others. Self-serving goals, such as anxiety reduction, self-esteem, and confirmation of one’s worldview, distort cognitive empathy. I consider these different strategies in light of hybrid theories of cognitive empathy. (shrink)

This paper explores the ambiguous impact of new information and communications technologies on the cultivation of moral skills in human beings. Just as twentieth century advances in machine automation resulted in the economic devaluation of practical knowledge and skillsets historically cultivated by machinists, artisans, and other highly trained workers , while also driving the cultivation of new skills in a variety of engineering and white collar occupations, ICTs are also recognized as potential causes of a complex pattern of economic deskilling, (...) reskilling, and upskilling. In this paper, I adapt the conceptual apparatus of sociological debates over economic deskilling to illuminate a different potential for technological deskilling/upskilling, namely the ability of ICTs to contribute to the moral deskilling of human users, a potential that exists alongside rich but currently underrealized possibilities for moral reskilling and/or upskilling. I flesh out this general hypothesis by means of examples involving automated weapons technology, new media practices, and social robotics. I conclude that since moral skills are essential prerequisites for the effective development of practical wisdom and virtuous character, and since market and cultural forces are not presently aligned to bring about the more salutary of the ambiguous potentials presented here, the future shape of these developments warrants our close attention—and perhaps active intervention. (shrink)

Psychologists have long noted the correlation between empathy and pro-social outcomes. Empathetic people are happier, healthier, more cooperative, and more altruistic than people who are less empathetic. However, empathy is not a panacea for all social ills. Critics argue that empathy is idiosyncratic, easily manipulated, biased in favour of one’s in-group, and exacerbates rather than relieving underlying inequalities. The praise and critique of empathy raise an interesting question: can we improve empathy? It depends on what kind of capacity empathy is. (...) The author argues that empathy comprises both skills and habits. Both skills and habits can be improved, though the process for improvement is quite different for each. The author argues that theoretical and empirical considerations support the idea that we can improve both the skills and habits that underlie empathy. If this is right, it shows that it is possible to harness the positive outcomes of empathy while avoiding some of its darker sides. (shrink)

Extended cognition is the view that some cognitive processes extend beyond the brain. One prominent strategy of arguing against extended cognition is to offer necessary conditions on cognition and argue that the proposed extended processes fail to satisfy these conditions. I argue that this strategy is misguided and fails to refute extended cognition. I suggest a better way to evaluate the case for extended cognition that should be acceptable to all parties, captures the intuitiveness of previous objections, and avoids the (...) problems with the strategy of offering necessary conditions on cognition. I conclude that extended cognition theorists have failed to establish the truth of extended cognition. (shrink)

Disagreeing with others about how to interpret a social interaction is a common occurrence. We often find ourselves offering divergent interpretations of others’ motives, intentions, beliefs, and emotions. Remarkably, philosophical accounts of how we understand others do not explain, or even attempt to explain such disagreements. I argue these disparities in social interpretation stem, in large part, from the effect of social categorization and our goals in social interactions, phenomena long studied by social psychologists. I argue we ought to expand (...) our accounts of how we understand others in order to accommodate these data and explain how such profound disagreements arise amongst informed, rational, well-meaning individuals. (shrink)

Direct Perception is the view that we can see others' mental states, i.e. that we perceive others' mental states with the same immediacy and directness that we perceive ordinary objects in the world. I evaluate Direct Perception by considering whether we can see intentions, a particularly promising candidate for Direct Perception. I argue that the view equivocates on the notion of intention. Disambiguating the Direct Perception claim reveals a troubling dilemma for the view: either it is banal or highly implausible.

"[A] lucid discussion of race that does not sell out the black experience." —Tommy Lott, author of The Invention of Race Revealing Whiteness explores how white privilege operates as an unseen, invisible, and unquestioned norm in society today. In this personal and selfsearching book, Shannon Sullivan interrogates her own whiteness and how being white has affected her. By looking closely at the subtleties of white domination, she issues a call for other white people to own up to their unspoken (...) privilege and confront environments that condone or perpetuate it. Sullivan’s theorizing about race and privilege draws on American pragmatism, psychology, race theory, and feminist thought. As it articulates a way to live beyond the barriers that white privilege has created, this book offers readers a clear and honest confrontation with a trenchant and vexing concern. (shrink)

The 2017 codetection of electromagnetic radiation and gravitational waves was the first of its kind and marked the beginning of multimessenger astronomy. But this event has been treated within recent literature as something of an end as well. The 2017 detection is often regarded as an instance of falsification for all theories of modified gravity which postulate gravitational waves propagate along separate geodesics from electromagnetic radiation, perhaps most notably Jacob Bekenstein’s Tensor-Vector-Scalar gravity. I critically examine this explicit endorsement of falsification (...) by astronomers and astrophysicists. While the current state of multimetric modified gravity theories is dim, recent developments in multimessenger observation do not offer a deductive falsification. Rather such evidence should be regarded as a corroboration of the null hypothesis, following Deborah Mayo's error-statistical account. (shrink)

Embodied social cognition (ESC) aims to explicate how our embodiment shapes our knowledge of others, and in what this knowledge of others consists. Although there is much diversity amongst ESC accounts, common to all these accounts is the idea that our normal everyday interactions consist in non-mentalistic embodied engagements. In recent years, several theorists have developed and defended innovative and controversial accounts of ESC. These accounts challenge, and offer deflationary alternatives to, the standard cognitivist accounts of social cognition. As ESC (...) accounts grow in number and prominence, the time has come for a dedicated, sustained debate on ESC and its most controversial and innovative elements. The goal of this special issue is to host such a debate with the aim of bringing clarity to the discussion of social cognition. (shrink)

: This paper demonstrates how John Dewey's notion of habit can help us understand gender as a constitutive structure of bodily existence. Bringing Dewey's pragmatism in conjunction with Judith Butler's concept of performativity, I provide an account of how rigid binary configurations of gender might be transformed at the level of both individual habit and cultural construct.

This paper develops a phenomenological defense of Ian Hacking's experimental realism about unobservable entities in physical science, employing historically undervalued resources from the phenomenological tradition in order to clarify the warrant for our ontological commitments in science. Building upon the work of Husserl, Merleau-Ponty and Heelan, the paper provides a phenomenological correction of the positivistic conception of perceptual evidence maintained by antirealists such as van Fraassen, the experimental relevance of which is illustrated through a phenomenological interpretation of the 1974 discovery (...) of the J/ ψ particle generally regarded as evidence for the charmed quark. The argument then turns to address known problems in Hacking's account, demonstrating that his own instrumentalist criterion of the real is inadequately rooted in the phenomenology of perception, and as a result, passes over the true ontological significance of experimental phenomena. The paper maintains that the proper criterion, only indirectly related to instrumentality, is the distinctive style of the real encountered in perception: empirical pregnancy. With this notion and Merleau-Ponty's associated reversibility thesis, I show that the phenomenological tradition provides insights into the warrant for our realist commitments that have yet to be adequately acknowledged by philosophers of science. (shrink)

"Radically reorienting, challenging, provocative, this book moves progressive philosophy, feminist and queer theory, critical discussions of race and racism forward. Prophetically, it calls for an interrogation of all our oppositional theory and politics, offering new and alternative visions." —bell hooks In Queering Freedom, Shannon Winnubst examines contemporary categories of difference—sexuality, race, gender, class, and nationality—and how they operate within the politics of domination. Drawing on the work of Georges Bataille, Michel Foucault, and others, Winnubst engages feminist theory, race theory, (...) and queer theory as she sheds light on blind spots that have characterized thinking about freedom. Winnubst turns away from the language of rights, identity politics, and liberation toward bodies and experiences to calibrate normative ideas of time and space. Her views operate at the very limits of freedom, which contain individuals within strict boundaries that they are forbidden to cross. Winnubst develops strategies of "queering freedom" to undo the more subtle spatial and temporal norms and shatter structures of domination. This thoughtful and provocative work challenges the cornerstones of contemporary philosophies about the body and its politics. (shrink)

: Responding to Silvia Stoller's comments on "Domination and Dialogue in Merleau-Ponty's Phenomenology of Perception" (Sullivan 1997), I argue that while phenomenology has much to offer feminism, feminists should be wary of Merleau-Ponty's notion of projective intentionality because of the ethical solipsism that it tends to involve. I also take the opportunity to clarify the concept of hypothetical construction introduced in the earlier paper, in particular the transformative relationship that it has to pre-reflective experience.

In this paper I evaluate embodied social cognition, embodied cognition’s account of how we understand others. I identify and evaluate three claims that motivate embodied social cognition. These claims are not specific to social cognition; they are general hypotheses about cognition. As such, they may be used in more general arguments for embodied cognition. I argue that we have good reasons to reject these claims. Thus, the case for embodied social cognition fails. Moreover, to the extent that general arguments for (...) embodied cognition rest on these premises, they are correspondingly uncompelling. (shrink)

Drawing from a variety of Hegel’s writings, Shannon Hoff articulates a theory of justice that requires answering simultaneously to three irreducibly different demands: those of community, universality, and individuality. The domains of “ethicality,” “legality,” and “morality” correspond to these essential dimensions of human experience, and a political system that fails to give adequate recognition to any one of these will become oppressive. The commitment to legality emphasized in modern and contemporary political life, Hoff argues, systematically precludes adequate recognition of (...) the formative cultural contexts that Hegel identifies under the name of “ethical life” and of singular experiences of moral duty, or conscience. Countering the perception of Hegel as a conservative political thinker and engaging broadly with contemporary work in liberalism, critical theory, and feminism, Hoff focuses on these themes of ethicality and conscience to consider how modern liberal politics must be transformed if it is to accommodate these essential dimensions of human life. (shrink)

We often have affective responses to fictional events. We feel afraid for Desdemona when Othello approaches her in a murderous rage. We feel disgust toward Iago for orchestrating this tragic event. What mental architecture could explain these affective responses? In this paper I consider the claim that the best explanation of our affective responses to fiction involves imaginative desires. Some theorists argue that accounts that do not invoke imaginative desires imply that consumers of fiction have irrational desires. I argue that (...) there are serious worries about imaginative desires that warrant skepticism about the adequacy of the account. Moreover, it is quite difficult to articulate general principles of rationality for desires, and even according to the most plausible of these possible principles, desires about fiction are not irrational. (shrink)

German philosopher and social critic Theodor Adorno (1903--1969) is widely regarded as one of the twentieth century's most influential thinkers. A leading member of the Frankfurt School, Adorno advanced an unconventional type of Marxist analysis in books such as Dialectic of Enlightenment (1944), Minima Moralia (1951), and Negative Dialectics (1966). Forced out of Nazi Germany because of his Jewish heritage, Adorno lived in exile in the United States for nearly fifteen years. In Adorno and Democracy, Shannon Mariotti explores how (...) this extended visit prompted a concern for and commitment to democracy that shaped the rest of his work. Mariotti analyzes the extensive and undervalued works Adorno composed in English for an American audience and traces the development of his political theory during the World War II era. Her unique study examines how Adorno changed his writing style while in the United States in order to directly address the public, which lay at the heart of his theoretical concerns. Despite his apparent contempt for popular culture, his work during this period clearly engages with a broader public in ways that reflect a deep desire to understand the problems and possibilities of democracy as enacted through the customs and habits of Americans. Ultimately, Adorno advances a theory of democratic leadership that works through pedagogy to cultivate a more robust and meaningful practice of citizenship. Mariotti incisively demonstrates how Adorno's unconventional and challenging interpretations of US culture can add conceptual rigor to political theory and remind Americans of the normative promise of democracy. Adorno and Democracy is an innovative contribution to critical debates about contemporary US politics. (shrink)

Using psychosocial acceleration theory, this multimethod, multi-reporter study examines how early adversity adaptively shapes the development of a self-regulation construct: effortful control. Investigation of links between early life harshness and unpredictability and the development of effortful control could facilitate a nuanced understanding of early environmental effects on cognitive and social development. Using the Building Strong Families national longitudinal data set, aspects of early environmental harshness and early environmental unpredictability were tested as unique predictors of effortful control at age 3 using (...) multiple regression. Early harshness variables were financial harshness, mothers’ and fathers’ observed parenting, mothers’ and fathers’ reported use of harsh discipline, and harsh neighborhood conditions. Early unpredictability was measured by number of paternal transitions. Cues of harshness, specifically observed unresponsive parenting, observed harsh parenting, and neighborhood harshness, did significantly negatively predict effortful control. Paternal transitions also significantly predicted effortful control, but in the opposite (i.e., positive) direction. The results corroborate previous research linking quality of parenting to the development of children’s effortful control and place it within an evolutionary-developmental theoretical framework. Further, the results suggest that neighborhood harshness may also direct developmental trajectories of effortful control in young children, though the mechanisms through which this occurs are still unclear. This is the first study to explicitly investigate effortful control development in early childhood within the harshness and unpredictability framework. (shrink)

A true Turing machine (TM) requires an infinitely long paper tape. Thus a TM can be housed in the infinite world of Newtonian spacetime (the spacetime of common sense), but not necessarily in our world, because our world-at least according to our best spacetime theory, general relativity-may be finite. All the same, one can argue for the "existence" of a TM on the basis that there is no such housing problem in some other relativistic worlds that are similar ("close") to (...) our world. But curiously enough-and this is the main point of this paper-some of these close worlds have a special spacetime structure that allows TMs to perform certain Turing unsolvable tasks. For example, in one kind of spacetime a TM can be used to solve first-order predicate logic and the halting problem. And in a more complicated spacetime, TMs can be used to decide arithmetic. These new computers serve to show that Church's thesis is a thoroughly contingent claim. Moreover, since these new computers share the fundamental properties of a TM in ordinary operation (e.g. intuitive, finitely programmed, limited in computational capability), a computability theory based on these non-Turing computers is no less worthy of investigation than orthodox computability theory. Some ideas about this new mathematical theory are given. (shrink)