YouTube has been implicated in the transformation of users into extremists and conspiracy theorists. The alleged mechanism for this radicalizing process is YouTube’s recommender system, which is optimized to amplify and promote clips that users are likely to watch through to the end. YouTube optimizes for watch-through for economic reasons: people who watch a video through to the end are likely to then watch the next recommended video as well, which means that more advertisements can be served to them. This (...) is a seemingly innocuous design choice, but it has a troubling side-effect. Critics of YouTube have alleged that the recommender system tends to recommend extremist content and conspiracy theories, as such videos are especially likely to capture and keep users’ attention. To date, the problem of radicalization via the YouTube recommender system has been a matter of speculation. The current study represents the first systematic, pre-registered attempt to establish whether and to what extent the recommender system tends to promote such content. We begin by contextualizing our study in the framework of technological seduction. Next, we explain our methodology. After that, we present our results, which are consistent with the radicalization hypothesis. Finally, we discuss our findings, as well as directions for future research and recommendations for users, industry, and policy-makers. (shrink)
In What the Body Commands, Colin Klein proposes and defends a novel theory of pain. Klein argues that pains are imperative; they are sensations with a content, and that content is a command to protect the injured part of the body. He terms this view "imperativism about pain," and argues that imperativism can account for two puzzling features of pain: its strong motivating power and its uninformative nature. Klein argues that the biological purpose of pain is homeostatic; like hunger and (...) thirst, pain helps solve a challenge to bodily integrity. It does so by motivating you to act in ways that help the body recover. If you obey pain's command, you get better. He develops his account to handle a variety of pain phenomena and applies it to solve a number of historically puzzling cases. Klein's intent is to defend the imperativist view in a pure form -- without requiring pain to represent facts about the world.Klein presents a model of imperative content showing that intrinsically motivating sensations are best understood as imperatives, and argues that pain belongs to this class. He considers the distinction between pain and suffering; explains how pain motivates; addresses variations among pains; and offers an imperativist account of maladaptive pains, pains that don't appear to hurt, masochism, and why pain feels bad. (shrink)
The so-called “dark room problem” makes vivd the challenges that purely predictive models face in accounting for motivation. I argue that the problem is a serious one. Proposals for solving the dark room problem via predictive coding architectures are either empirically inadequate or computationally intractable. The Free Energy principle might avoid the problem, but only at the cost of setting itself up as a highly idealized model, which is then literally false to the world. I draw at least one optimistic (...) conclusion, however. Real-world, real-time systems may embody motivational states in a variety of ways consistent with idealized principles like FEP, including ways that are intuitively embodied and extended. This may allow predictive coding theorists to reconcile their account with embodied principles, even if it ultimately undermines loftier ambitions. (shrink)
Since its introduction, multivariate pattern analysis, or ‘neural decoding’, has transformed the field of cognitive neuroscience. Underlying its influence is a crucial inference, which we call the decoder’s dictum: if information can be decoded from patterns of neural activity, then this provides strong evidence about what information those patterns represent. Although the dictum is a widely held and well-motivated principle in decoding research, it has received scant philosophical attention. We critically evaluate the dictum, arguing that it is false: decodability is (...) a poor guide for revealing the content of neural representations. However, we also suggest how the dictum can be improved on, in order to better justify inferences about neural representation using MVPA. 1Introduction 2A Brief Primer on Neural Decoding: Methods, Application, and Interpretation 2.1What is multivariate pattern analysis? 2.2The informational benefits of multivariate pattern analysis 3Why the Decoder’s Dictum Is False 3.1We don’t know what information is decoded 3.2The theoretical basis for the dictum 3.3Undermining the theoretical basis 4Objections and Replies 4.1Does anyone really believe the dictum? 4.2Good decoding is not enough 4.3Predicting behaviour is not enough 5Moving beyond the Dictum 6Conclusion. (shrink)
Pain asymbolics feel pain, but act as if they are indifferent to it. Nikola Grahek argues that such patients present a clear counterexample to motivationalism about pain. I argue that Grahek has mischaracterized pain asymbolia. Properly understood, asymbolics have lost a general capacity to care about their bodily integrity. Asymbolics’ indifference to pain thus does not show something about the intrinsic nature of pain ; it shows something about the relationship between pains and subjects, and how that relationship might break (...) down. I explore the consequences of such a view for both motivationalism and the categorization of pain asymbolia as a syndrome, arguing for a close link between asymbolia and various forms of depersonalization. (shrink)
The surface grammar of reports such as ‘I have a pain in my leg’ suggests that pains are objects which are spatially located in parts of the body. We show that the parallel construction is not available in Mandarin. Further, four philosophically important grammatical features of such reports cannot be reproduced. This suggests that arguments and puzzles surrounding such reports may be tracking artefacts of English, rather than philosophically significant features of the world.
Recent work on signaling has mostly focused on communication between organisms. The Lewis–Skyrms framework should be equally applicable to intra-organismic signaling. We present a Lewis–Skyrms signaling-game model of painful signaling, and use it to argue that the content of pain is predominantly imperative. We address several objections to the account, concluding that our model gives a productive framework within which to consider internal signaling.
Hypocrites invite moral opprobrium, and charges of hypocrisy are a significant and widespread feature of our moral lives. Yet it remains unclear what hypocrites have in common, or what is distinctively bad about them. We propose that hypocrites are persons who have undermined their claim to moral authority. Since this self-undermining can occur in a number of ways, our account construes hypocrisy as multiply realizable. As we explain, a person’s moral authority refers to a kind of standing that they occupy (...) within a particular moral community. This status is both socially important and normatively precarious. Hence, moral agents are right to be vigilant when it comes to hypocrisy, and are often justified in their outrage when they detect it. We further argue that our view can preserve what is attractive in rival accounts, while avoiding their associated problems. (shrink)
The interpretation of functional imaging experiments is complicated by the pluripotency of brain regions. As there is a many-to-one mapping between cognitive functions and their neural substrates, region-based analyses of imaging data provide only weak support for cognitive theories. Price and Friston argue that we need a ‘cognitive ontology’ that abstractly categorizes the function of regions. I argue that abstract characterizations are unlikely to be cognitively interesting. I argue instead that we should attribute functions to regions in a context-sensitive manner. (...) I review recent meta-analyses that approach fMRI data in this light and argue that they have revisionary potential. (shrink)
fMRI promises to uncover the functional structure of the brain. I argue, however, that pictures of ‘brain activity' associated with fMRI experiments are poor evidence for functional claims. These neuroimages present the results of null hypothesis significance tests performed on fMRI data. Significance tests alone cannot provide evidence about the functional structure of causally dense systems, including the brain. Instead, neuroimages should be seen as indicating regions where further data analysis is warranted. This additional analysis rarely involves simple significance testing, (...) and so justified skepticism about neuroimages does not provide reason for skepticism about fMRI more generally. (shrink)
Since its introduction, multivariate pattern analysis, or ‘neural decoding’, has transformed the field of cognitive neuroscience. Underlying its influence is a crucial inference, which we call the decoder’s dictum: if information can be decoded from patterns of neural activity, then this provides strong evidence about what information those patterns represent. Although the dictum is a widely held and well-motivated principle in decoding research, it has received scant philosophical attention. We critically evaluate the dictum, arguing that it is false: decodability is (...) a poor guide for revealing the content of neural representations. However, we also suggest how the dictum can be improved on, in order to better justify inferences about neural representation using MVPA. (shrink)
Protests and counter-protests seek to draw and direct attention and concern with confronting images and slogans. In recent years, as protests and counter-protests have partially migrated to the digital space, such images and slogans have also gone online. Two main ways in which these images and slogans are translated to the online space is through the use of emoji and hashtags. Despite sustained academic interest in online protests, hashtag activism and the use of emoji across social media platforms, little is (...) known about the specific functional role that emoji and hashtags play in online social movements. In an effort to fill this gap, the current paper studies both hashtags and emoji in the context of the Twitter discourse around the Black Lives Matter movement. (shrink)
Explores the place of intellectual virtues and vices in a social world. Chapters are divided into four sections: Foundational Issues; Individual Virtues; Collective Virtues; and Methods and Measurements.
Unlike the overall framework of Ernest Nagel's work on reduction, his theory of intertheoretic connection still has life in it. It handles aptly cases where reduction requires complex representation of a target domain. Abandoning his formulation as too liberal was a mistake. Arguments that it is too liberal at best touch only Nagel's deductivist theory of explanation, not his condition of connectability. Taking this condition seriously gives a powerful view of reduction, but one which requires us to index explanatory power (...) to sciences as they are formulated at particular times. While we may thereby reduce more than philosophers have supposed, we must abandon hope (as Nagel did) of saying anything useful about reductionism. (shrink)
Functional neuroimaging (NI) technologies like Positron Emission Tomography and functional Magnetic Resonance Imaging (fMRI) have revolutionized neuroscience, and provide crucial tools to link cognitive psychology and traditional neuroscientific models. A growing discipline of 'neurophilosophy' brings fMRI evidence to bear on traditional philosophical issues such as weakness of will, moral psychology, rational choice, social interaction, free will, and consciousness. NI has also attracted critical attention from psychologists and from philosophers of science. I review debates over the evidential status of fMRI, including (...) the differences between brain scans and ordinary images, the legitimacy of forward inference and reverse inference, and deductive versus probabilistic accounts of NI evidence. I conclude with a discussion of fMRI as exploratory rather than confirmatory evidence, linking this debate to the growing literature on cognitive ontology. (shrink)
The dual-track theory of moral reasoning has received considerable attention due to the neuroimaging work of Greene et al. Greene et al. claimed that certain kinds of moral dilemmas activated brain regions specific to emotional responses, while others activated areas specific to cognition. This appears to indicate a dissociation between different types of moral reasoning. I re-evaluate these claims of specificity in light of subsequent empirical work. I argue that none of the cortical areas identified by Greene et al. are (...) functionally specific: each is active in a wide variety of both cognitive and emotional tasks. I further argue that distinct activation across conditions is not strong evidence for dissociation. This undermines support for the dual-track hypothesis. I further argue that moral decision-making appears to activate a common network that underlies self-projection: the ability to imagine oneself from a variety of viewpoints in a variety of situations. I argue that the utilization of self-projection indicates a continuity between moral decision-making and other kinds of complex social deliberation. This may have normative consequences, but teasing them out will require careful attention to both empirical and philosophical concerns. (shrink)
At present, the science of consciousness is structured around the search for the neural correlates of consciousness. One of the alleged advantages of the NCCs framework is its metaphysical neutrality—the fact that it begs no contested questions with respect to debates about the fundamental nature of consciousness. Here, we argue that even if the NCC framework is metaphysically neutral, it is structurally committed, for it presupposes a certain model—what we call the Lite-Brite model—of consciousness. This, we argue, represents a serious (...) liability for the NCC framework for the plausibility of the Lite-Brite model is very much an open question, and the science of consciousness would be better served by a framework that does not presuppose it. Drawing on interventionist ideas in the philosophy of science, we suggest that the Difference-Maker framework can provide just such an alternative. Instead of searching for the neural correlates of consciousness, we ought to be searching for the difference makers of consciousness. We detail how a shift to searching DMCs will change both the practice of consciousness science and the interpretation of existing results. (shrink)
YouTube has been implicated in the transformation of users into extremists and conspiracy theorists. The alleged mechanism for this radicalizing process is YouTube’s recommender system, which is optimized to amplify and promote clips that users are likely to watch through to the end. YouTube optimizes for watch-through for economic reasons: people who watch a video through to the end are likely to then watch the next recommended video as well, which means that more advertisements can be served to them. This (...) is a seemingly innocuous design choice, but it has a troubling side-effect. Critics of YouTube have alleged that the recommender system tends to recommend extremist content and conspiracy theories, as such videos are especially likely to capture and keep users’ attention. To date, the problem of radicalization via the YouTube recommender system has been a matter of speculation. The current study represents the first systematic, pre-registered attempt to establish whether and to what extent the recommender system tends to promote such content. We begin by contextualizing our study in the framework of technological seduction. Next, we explain our methodology. After that, we present our results, which are consistent with the radicalization hypothesis. Finally, we discuss our findings, as well as directions for future research and recommendations for users, industry, and policy-makers. (shrink)
Some vegetative state patients show fMRI responses similar to those of healthy controls when instructed to perform mental imagery tasks. Many authors have argued that this provides evidence that such patients are in fact conscious, as response to commands requires intentional agency. I argue for an alternative reading, on which responsive patients have a deficit similar to that seen in severe forms of akinetic mutism. Akinetic mutism is marked by the inability to form and maintain intentions to act. Responsive patients (...) are likely still conscious. However, the route to this conclusion does not support attributions of intentional agency. I argue that aspects of consciousness, rather than broad diagnostic categories, are the more appropriate target of empirical investigation. Investigating aspects of consciousness provides a better method for investigating profound disorders of consciousness. 1 Introduction2 Responses in the Vegetative State2.1 The imaging evidence2.2 The need for models3 Responsive Patients and Akinetic Mutism3.1 Akinetic mutism3.2 Akinetic mutism as a deficit in intentions3.3 Arguments for the link3.4 Interim conclusion4 Other Models4.1 A deficit in ability?4.2 Modular intentions?5 Consciousness and Method5.1 Are they conscious?5.2 Aspects versus levels. (shrink)
This editorial introduces the Journal of Consciousness Studies special issue on "Animal Consciousness". The 15 contributors and co-editors answer the question "How should we study animal consciousness scientifically?" in 500 words or fewer.
Being whipped, getting a deep-tissue massage, eating hot chili peppers, running marathons, and getting tattooed are all painful. Sometimes they are also pleasant—or so many people claim. Masochistic pleasure consists in finding such experiences pleasant in addition to, and because of, the pain. Masochistic pleasure presents a philosophical puzzle. Pains hurt, they feel bad, and are aversive. Pleasures do the opposite. Thus many assume that the idea of a pleasant pain is downright unintelligible. I disagree. I claim that cases of (...) pleasant pains are more common than many philosophers suppose, and that they have no essential connection to either sex or psychopathology. I review several attempts to account for masochism that preserve the intuition that nothing can be both pleasant and painful at once. These account for some, but not all, cases of masochism. The stubborn remainder, I argue, are sensations that are genuinely pleasant and painful at once. I give an account of how that might be, focusing on boundary-pushing aspects of masochistic pleasure that have been largely overlooked in the literature. I show how, properly understood, pain and pleasure can coexist—and also why it is very rare for them to actually do so. (shrink)
Multiply realizable properties are those whose realizers are physically diverse. It is often argued that theories which contain them are ipso facto irreducible. These arguments assume that physical explanations are restricted to the most specific descriptions possible of physical entities. This assumption is descriptively false, and philosophically unmotivated. I argue that it is a holdover from the late positivist axiomatic view of theories. A semantic view of theories, by contrast, correctly allows scientific explanations to be couched in the most perspicuous, (...) powerful language available. On a semantic view, traditional notions of multiple realizability are thus very hard to motivate. At best, one must abandon either the idea that multiple realizability is an interesting scientific notion, or else admit that multiply realizable properties do not automatically block scientific reductions. (shrink)
This special issue brings together philosophical perspectives on the debate over cognitive ontology. We contextualize the papers in this issue by considering several different senses of the term “cognitive ontology” and linking those debates to traditional debates in philosophy of mind.
Several authors have recently argued that the content of pains (and bodily sensations more generally) is imperative rather than descriptive. I show that such an account can help resolve competing intuitions about phantom limb pain. As imperatives, phantom pains are neither true nor false. However, phantom limb pains presuppose falsehoods, in the same way that any imperative which demands something impossible presupposes a falsehood. Phantom pains, like many chronic pains, are thus commands that cannot be satisfied. I conclude by showing (...) that some of the negative psychological consequences of chronic pain are a direct consequence of their imperative nature. (shrink)
Conspiracy theories play a troubling role in political discourse. Online forums provide a valuable window into everyday conspiracy theorizing, and can give a clue to the motivations and interests of those who post in such forums. Yet this online activity can be difficult to quantify and study. We describe a unique approach to studying online conspiracy theorists which used non-negative matrix factorization to create a topic model of authors' contributions to the main conspiracy forum on Reddit. This subreddit provides a (...) large corpus of comments which spans many years and numerous authors. We show that within the forum, there are multiple sub-populations distinguishable by their loadings on different topics in the model. Further, we argue, these differences are interpretable as differences in background beliefs and motivations. The diversity of the distinct subgroups places constraints on theories of what generates conspiracy theorizing. We argue that traditional “monological” believers are only the tip of an iceberg of commenters. Neither simple irrationality nor common preoccupations can account for the observed diversity. Instead, we suggest, those who endorse conspiracies seem to be primarily brought together by epistemological concerns, and that these central concerns link an otherwise heterogenous group of individuals. (shrink)
Contrastive neuroimaging is often taken to provide evidence about the localization of cognitive functions. After canvassing some problems with this approach, I offer an alternative: neuroimaging gives evidence about regions of the brain that bear difference-making relationships to psychological processes of interest. I distinguish between the specificity and what I call the systematicity of a difference-making relationship, and I show how at least some neuroimaging experiments can give evidence for systematic difference-making.
Distinguishing mechanistic components from mere causally relevant background conditions remains a difficulty for mechanistic accounts of explanation. By distinguishing resources from mechanical parts, I argue that we can more effectively draw this boundary. Further, the distinction makes obvious that there are distinctive resource explanations which are not captured by a traditional part-based mechanistic account. While this suggests a straightforward extension of the mechanistic model, I argue that incorporating resources and resource explanations requires moving beyond the purely local account of levels (...) that some mechanists advocate. (shrink)
Consciousness supervenes on activity; computation supervenes on structure. Because of this, some argue, conscious states cannot supervene on computational ones. If true, this would present serious difficulties for computationalist analyses of consciousness (or, indeed, of any domain with properties that supervene on actual activity). I argue that the computationalist can avoid the Superfluous Structure Problem (SSP) by moving to a dispositional theory of implementation. On a dispositional theory, the activity of computation depends entirely on changes in the intrinsic properties of (...) implementing material. As extraneous structure is not required for computation, a system can implement a program running on some but not all possible inputs. Dispositional computationalism thus permits episodes of computational activity that correspond to potential episodes of conscious awareness. The SSP cannot be motivated against this account, and so computationalism may be preserved. (shrink)
This chapter focuses on evidence from functional magnetic resonance imaging data, and discusses the application of neuroimaging techniques to various fields, including cognitive sciences. It considers the role of neuroimaging data in providing informative evidence regarding hypotheses in cognitive science, and explains differences in data, high-level null hypotheses, and ways to accommodate null hypotheses. Finally, the chapter looks into the scope of neuroimaging data in the cognitive sciences.
Neuroimaging studies of the resting state continue to gather philosophical and scientific attention. Most discussions assume an identification between resting-state activity and activity in the so-called default mode network. I argue we should resist this identification, structuring my discussion around a dilemma first posed by Morcom and Fletcher. I offer an alternative view of rest as a state dominated by long-term processes and show how interaction effects might thereby let rest shed light on short-term changes in activation.
Multiply realizable kinds are scientifically problematic, for it appears that we should not expect discoveries about them to hold of other members of that kind. As such, it looks like MR kinds should have no place in the ontology of the special sciences. Many resist this conclusion, however, because we lack a positive account of the role that certain realization-unrestricted terms play in special science explanations. I argue that many such terms actually pick out idealizing models. Idealizing explanation has many (...) of the features normally associated with explanation by MR kinds. As idealized models are usually mere possibilia, such explanations do not run afoul of the metaphysical problems that plague MR kinds. (shrink)
Computers are used to make decisions in an increasing number of domains. There is widespread agreement that some of these uses are ethically problematic. Far less clear is where ethical problems arise, and what might be done about them. This paper expands and defends the Ethical Gravity Thesis: ethical problems that arise at higher levels of analysis of an automated decision-making system are inherited by lower levels of analysis. Particular instantiations of systems can add new problems, but not ameliorate more (...) general ones. We defend this thesis by adapting Marr’s famous 1982 framework for understanding information-processing systems. We show how this framework allows one to situate ethical problems at the appropriate level of abstraction, which in turn can be used to target appropriate interventions. (shrink)
Frédérique de Vignemont argues on the basis of several empirical counterexamples that Bain and Klein are wrong about the relationship between pain and bodily care. I argue that the force of the putative counterexamples is weak. Properly understood, the association between pain and care is preserved in a way that is consistent with both de Vignemont's own views and the empirical facts.
Kohler's experiments with inverting goggles are often thought to support enactivism by showing that visual re-inversion occurs simultaneous with the return of sensorimotor skill. Closer examination reveals that Kohler's work does not show this. Recent work by Linden et al. shows that re-inversion, if it occurs at all, does not occur when the enactivist predicts. As such, the empirical evidence weighs against enactivism.
Robert Rupert is well-known as an vigorous opponent of the hypothesis of extended cognition (HEC). His Cognitive Systems and the Extended Mind is a first-rate development of his “systems-based” approach to demarcating the mind. The results are impressive. Rupert’s account brings much-needed clarity to the often-frustrating debate over HEC: much more than just an attack on HEC, he gives a compelling picture of why the debate matters.
In a target article that appeared in this journal, Thomas Stoffregen 2000 questions the possibility of ecological event perception research. This paper describes an experiments performed to examine the perception of the disappearance of gap-crossing affordances, a variety of event as defined by Chemero 2000. We found that subjects reliably perceive both gap-crossing affordances and the disappearance of gap-crossing affordances. Our findings provide empirical evidence in favor of understanding events as changes in the layout of affordances, shoring up event perception (...) research in ecological psychology. (shrink)
Maura Tumulty has raised two objections to my imperative account of pain.1 First, she argues that there is a disanalogy between pains and other imperative sensations like itch, hunger, and thirst. Suppose (with Hall) one thinks that an itch says “Scratch here!”2 Scratch the itch, and it dutifully disappears. Not so with pain. The pain of a broken ankle has the content ‘Do not put weight on that ankle!’ Yet the coddled ankle still throbs: obeying the imperative does not extinguish (...) it. Second, Tumulty argues that the imperative account cannot handle certain pains, particularly pains of the deep viscera. On my account, pains proscribe against taking action with the painful body part. Yet some pains are associated with body parts over which we have no control. Kidney stones cause intense pain, but I cannot (voluntarily) control my kidney. What action, then, could that pain possibly proscribe? Lacking such a story, it is hard to say (as I do) that pains are exhausted by their imperative content. (shrink)
In this paper we analyses the work of the first century Chinese philosopher Wang Chong as in part grappling with epistemology of testimony. Often portrayed as a curmudgeonly skeptic, Wang Chong actually best seen as a demanding piecemeal non-reductionist, which is to say he believed that testimony was a basic source of evidence unless subject to a defeater (non-reductionism), but also that we should evaluate testimony on a claim-by-claim basis (piecemeal) rather than accepting a whole source on the strength of (...) its reputation or authority, and finally he thought one has a strong duty to search for defeaters (demanding). We defend each of these claims as well as the fruitfulness of applying such anachronistic terminology to an ancient thinker. We end with a discussion of how Wang Chong's epistemology relates to his rhetorical method and then consider some problems he faces because of his epistemic commitments. (shrink)
I argue that computationalism is compatible with a plausible supervenience thesis about conscious states. The most plausible way of making it compatible, however, involves abandoning counterfactual conditions on implementation.
Robert Rupert is well-known as a vigorous opponent of the hypothesis of extended cognition . His Cognitive Systems and the Extended Mind is a first-rate development of his "systems-based" approach to demarcating the mind. The results are impressive. Rupert's account brings much-needed clarity to the often-frustrating debate over HEC: much more than just an attack on HEC, he gives a compelling picture of why the debate matters.
Anderson's meta-analysis of fMRI data is subject to a potential confound. Areas identified as active may make no functional contribution to the task being studied, or may indicate regions involved in the coordination of functional networks rather than information processing per se. I suggest a way in which fMRI adaptation studies might provide a useful test between these alternatives.
Epidemiological models directly shape policy responses to public health crises. We argue that they also play a less obvious but important role in solving certain coordination problems and social dilemmas that arise during pandemics. This role is both ethically and epistemically valuable. However, it also gives rise to an underappreciated dilemma, as the features that make models good at solving coordination problems are often at odds with the features that make for a good scientific model. We examine and develop this (...) dilemma in the context of the COVID-19 pandemic, and suggest extensions to other domains. (shrink)
In their “The Prevalence of Mind-Body Dualism in Early China,” Slingerland and Chudek use a statistical analysis of the early Chinese corpus to argue for Weak Folk Dualism (WFD). We raise three methodological objections to their analysis. First, the change over time that they find is largely driven by genre. Second, the operationalization of WFD is potentially misleading. And, third, dating the texts they use is extremely controversial. We conclude with some positive remarks.
Functional magnetic resonance imaging (or fMRI)1 is widely used to support hypotheses about brain function. Many find the images produced from fMRI data to be especially compelling evidence for scientific hypotheses [McCabe and Castel, 2008]. There are many problems with all of this; I want to start with two of them, and argue that they get us closer to an under-appreciated worry about many imaging experiments.
Amputation of a limb can result in the persistent hallucination that the limb is still present [Ramachandran and Hirstein, 1998]. Distressingly, these socalled ‘phantom limbs’ are often quite painful. Of a friend whose arm had been amputated due to gas gangrene, W.K. Livingston writes: I once asked him why the sense of tenseness in the hand was so frequently emphasized among his complaints. He asked me to clench my fingers over my thumb, flex my wrist, and raise the arm into (...) a hammerlock position and hold it there. He kept me in this position as long as I could stand it. At the end of five minutes I was perspiring freely, my hand and arm felt unbearably cramped, and I quit. But you can take your hand down, he said. (quoted in [Melzack, 1973] 53) In addition to the obvious medical issues, phantom limb pain also presents philosophical problems. Here’s a thorny one: are phantom limb pains hallucinations of pain? (shrink)