Glenn Carruthers

In recent years, phenomenologically informed philosophers, psychologists and psychiatrists have attempted to import philosophical notions associated with the self into the empirical study of pathological experience. In particular, so-called ipseity disturbances have been put forward as generative of symptoms of schizophrenia, and several attempts have been made to operationalize and measure kinds and degrees of ipseity disturbances in schizophrenia. However, we find that this work faces challenges caused by the fact that the notion of ipseity is used ambiguously, both in the philosophical and in the empirical discussion, and the methods employed to operationalize ipseity often portray a rather different understanding of the notion from that found in the literature that is cited as providing the philosophical foundation for the studies in question. In particular, according to the definitions found in the philosophical literature, while being phenomenologically available, the self is not represented in ipseity. However, when it comes to the empirical study of ipseity and its disturbances, the object of investigation is often a kind of explicit self-representation. As a result, it is unclear whether different researchers are really talking about the same thing. Future progress in this area will require more careful conceptual distinctions; the present article aims to contribute to this task.

In this paper we try to diagnose one reason why the debate regarding the Hard Problem of consciousness inevitably leads to a stalemate: namely that the characterisation of consciousness assumed by the Hard Problem is unjustified and probably unjustifiable. Following Dennett (Consciousness explained. Penguin Books, New York, 1991, J Conscious Stud 3(1): 4–6, 1996, Cognition 79:221–237, 2001, J Conscious Stud 19(1):86, 2012) and Churchland (J Conscious Stud 3(5–6):402–408, 1996, Brainwise: studies in neurophilosophy. MIT Press, Cambridge, MA, 2002), we argue that there is in fact no non-question begging argument for the claim that consciousness is a uniquely Hard Phenomenon. That is; there is no non-question begging argument for the claim that consciousness is necessarily in explicable in terms of the structure and function of mental states. Unfortunately the debate has not moved on because the majority of materialists feel the pull of the at least one of, what we call, the ‘key’ intuitions that supposedly support dualism and the existence of a Hard Phenomenon and so try to accommodate them rather than denying them. Although this a possible response to the intuitions it tends to mask the fact that there is in fact no argument for the existence of a Hard Phenomenon. So we end up participating in our own hornswoggling (Churchland in J Conscious Stud 3, (5–6):402–408, 1996) and chasing our tails trying to answer a question we should in fact ignore. We have no reason to think there is a Hard Problem of consciousness because we have no reason to think the Hard Phenomenon exists.

In Chapter 4 Carruthers offers a well-motivated hypothesis to explain the phenomenology of the feeling of embodiment that has received some independent and direct empirical support. But, is this an account of our consciousness of this feeling or just how the content is represented? In this chapter Carruthers considers what Dennett has called the “Hard Question” of consciousness. The account offered in Chapter 4 undoubtedly does a good job of explaining how the representations of our own embodiment are elicited. But, how are we to distinguish conscious and unconscious representations of our own embodiment? Carruthers considers two possible answers to this problem known as vehicle and functionalist accounts of consciousness. The explanation offered so far is classified as a vehicle theory.

Carruthers offers a description of the feeling of embodiment, or the experience of oneself as one’s body, as me. This discussion is driven by experimental and pathological alterations to the feeling of embodiment as seen in the rubber hand illusion (RHI), the delusion of somatoparaphrenia and body integrity identity disorder. From this the feeling of embodiment is distinguished from the sense of ownership of the body. The Real Problem of Consciousness introduced in Chapter 10.1007/978-3-030-14167-7_1 returns here: there are circumstances where we cannot be confident that reports are a valid and reliable measure of the feeling of embodiment. However, Carruthers argues that using well-designed questionnaires, corroborative measures and by grouping reports into types that we can make progress on the Real Problem.

Carruthers offers an explanation of the phenomenology of the feeling of embodiment. He argues that the sense of embodiment arises when an on-line representation of the body is represented as matching an off-line prototype representation of what one’s body is usually like. A distinguishing feature of this model is the off-line body representation. Carruthers proposes that the off-line representation is a point in a quality space which corresponds to a prototype arrangement of one’s own body. This explanation is both causal and constitutive. This offers a testable explanation of how the feeling of embodiment is elicited in the rubber hand illusion (RHI) and the loss of the feeling in the delusion somatoparaphrenia, in which patients deny that a part of their body is theirs.

Carruthers introduces some of the tools needed for the explanation of the feeling of embodiment. From the experiences and abilities of patients suffering anosognosia for hemiplegia we find at least two separate ways of representing the body, called on-line and off-line body representations. Sufferers of anosognosia are generally unaware of paralysis or severe weakness caused by a stroke or other brain damage. However, these patients can be made temporarily aware of their paralysis or weakness and there is evidence that the new state of their body is usually represented unconsciously. This is explained by the difference between on-line and off-line body representations and how they are accessed. Having drawn this distinction, it seems that off-line representations play an important role in the sense of embodiment.

Carruthers returns to methodological problems of measuring the feeling of embodiment and examines the implications these problems have for the explanation offered in the previous chapters. Carruthers considers the possibility of confabulated reports of experience, or, people reporting experiences they didn’t actually have, yet sincerely believe they had. Carruthers argues that pure vehicle theories such as that offered so far in the book cannot accommodate confabulations. After establishing that such confabulations exist, Carruthers offers a hybrid account. The account offered so far explains the phenomenal qualities of the feeling of embodiment, but a functionalist account is needed to explain the subjects’ awareness of those properties, to accommodate confabulations and to explain why sometimes confabulations cannot be distinguished from veridical reports.

Carruthers considers a challenge to hybrid accounts of consciousness from recent arguments offered by Irvine to the effect that this concept of AWARENESS is not a scientifically respectable kind. From the fact that different measures of consciousness can provide contradictory answers to questions of what a subject is conscious of, Irvine concludes that each measure taps a different cognitive process rather than a unified phenomenon of consciousness. Carruthers argues that some explanations of awareness called “functional emergence” accounts are not threatened by her arguments as they predict the existence of mental states of which the subject is neither aware nor unaware. Responding to Irvine’s argument also has the added benefit of allowing us to explore how to further study awareness according to the hybrid account.

In this paper we try to diagnose one reason why the debate regarding the Hard Problem of consciousness inevitably leads to a stalemate: namely that the characterisation of consciousness assumed by the Hard Problem is unjustified and probably unjustifiable. Following Dennett (Consciousness explained. Penguin Books, New York, 1991, J Conscious Stud 3(1): 4–6, 1996, Cognition 79:221–237, 2001, J Conscious Stud 19(1):86, 2012) and Churchland (J Conscious Stud 3(5–6):402–408, 1996, Brainwise: studies in neurophilosophy. MIT Press, Cambridge, MA, 2002), we argue that there is in fact no non-question begging argument for the claim that consciousness is a uniquely Hard Phenomenon. That is; there is no non-question begging argument for the claim that consciousness is necessarily in explicable in terms of the structure and function of mental states. Unfortunately the debate has not moved on because the majority of materialists feel the pull of the at least one of, what we call, the ‘key’ intuitions that supposedly support dualism and the existence of a Hard Phenomenon and so try to accommodate them rather than denying them. Although this a possible response to the intuitions it tends to mask the fact that there is in fact no argument for the existence of a Hard Phenomenon. So we end up participating in our own hornswoggling (Churchland in J Conscious Stud 3, (5–6):402–408, 1996) and chasing our tails trying to answer a question we should in fact ignore. We have no reason to think there is a Hard Problem of consciousness because we have no reason to think the Hard Phenomenon exists.

Objective To review the way consciousness is operationalised in contemporary research, discuss strengths and weaknesses of current approaches and propose new measures. Method We first reviewed the literature pertaining to the phenomenal character of visual and self-consciousness as well as awareness of visual stimuli. We also reviewed more problematic cases of dreams and animal consciousness, specifically that of octopuses. Results Despite controversies, work in visual and self consciousness is highly developed and there are notable successes. Cases where experiences are not induced, such as dreams, and where no verbal report is possible, such as when we study purported experiences of octopuses, are more challenging. It is difficult to be confident about the reliability and validity of operationalisations of dreams. Although this is a general concern about the measuring consciousness, it is not a sufficiently severe concern to completely undermine the work reviewed on vision and self-consciousness. It is more difficult to see how the good work on human psychology can be applied to non-human animals, especially those with radically different nervous systems, such as octopuses. Given the limitations of report-based operationalisations of consciousness, it is desirable to develop non-report-based measures, particularly for phenomenal qualities. We examine a number of possibilities and offer two possible approaches of varying degrees of practicality, the first based on combining quality space descriptions of phenomenal qualities and the notion of a “neural activation space” inherited from connectionist A.I., the second being a novel match to target approach Conclusion Consciousness is a multifacted phenomenon and requires a variety of operationalisations to be studied.

This book proposes a novel and rigorous explanation of consciousness. It argues that the study of an aspect of our self-consciousness known as the ‘feeling of embodiment’ teaches us that there are two distinct phenomena to be targeted by an explanation of consciousness. First is an explanation of the phenomenal qualities – 'what it is like' – of the experience; and second is the subject's awareness of those qualities. Glenn Carruthers explores the phenomenal qualities of the feeling of embodiment using the tools of quality spaces, as well as the subject's awareness of those qualities as a functionally emergent property of various kinds of processing of these spaces. Where much recent work on consciousness focuses on visual experience, this book rather draws evidence from the study of self-consciousness. Carruthers argues that in light of recent methodological discoveries, awareness must be explained in terms of the organization of multiple cognitive processes. The book offers an explanation of anomalous body representations and, from that, poses a more general theory of consciousness. Ultimately this book creates a hybrid account of consciousness that explains phenomenology and awareness using different tools. It will be of great interest to all scholars of psychology and philosophy as well as anyone interested in exploring the intricacies of how we experience our bodies, what we are and how we fit into the world.

Difficulties in distinguishing veridical reports of experience from confabulations have implications for theories of consciousness. I develop some of these implications through a consideration of out-of-body experiences (OBEs). Do these variations indicate individual variation in experience or are they post-hoc confabulations, stories told by subjects to themselves in an attempt to make sense of the core phenomenology? I argue that no existent or possible evidence would be sufficient to favour one hypothesis over the other. How such evidence is interpreted depends on prior commitments to one or other of these hypotheses or to a theory of consciousness that is not neutral as to these hypotheses. One of these types of theory, namely vehicle theories, has difficulty accommodating the existence of confabulations and so allows for only the elaborate phenomenology hypothesis. Because we cannot know that reports are not confabulations, vehicle theories are insufficient to explain OBEs.

The experience of embodiment may be studied using the rubber hand illusion. Little is known about the cognitive mechanism that elicits the feeling of embodiment. In previous models of the rubber hand illusion, bodily signals are processed sequentially. Such models cannot explain some more recent findings. Carruthers (2013) proposed a multidimensional model of embodiment, in which the processing of embodiment is understood in terms of conceptual hand space. Visual features of hands are represented along several dimensions. The rubber hand illusion is then explained as the erroneous matching of the online representation of the artificial hand to the stored prototype in a space defined by those dimensions. We conducted the first experimental tests to investigate the multidimensional conceptual space account. First, participants performed a series of odd-one-out judgments for triads of hand images (including their own hand) and we then employed multidimensional scaling analyses. We found that a multidimensional model of perceived hand similarity could be fitted to our data. Second, we tested if a multisensory bodily signal manipulation (the rubber hand illusion) influences the position of the viewed artificial hand in hand space. We employed synchronous and asynchronous stroking and found that in the synchronous condition, which elicits the rubber hand illusion, compared to the asynchronous condition, which does not, the artificial hand was closer to the center of hand space; that is, to a prototype hand. We discuss these findings in the context of the Carruthers (2013) conceptual space model as well as other rubber hand illusion models.

The phenomenology of the self includes the sense of control over one’s body and mind, of being bounded in body and mind, of having perspective from within one’s body and mind and of being extended in time. I argue that this phenomenology is to be accounted for by a set of five dissociable cognitive capacities that compose the self. The focus of this paper is on the four capacities that compose the synchronic self: the agentiveB self, which underlies the sense of control over one’s body; the boundaryB self, which underlies the sense of being bounded within one’s body; the agentiveM self which underlies the sense of control over one’s thoughts; and the boundaryM self which underlies the sense of being bounded within one’s mind. I model the agentiveB and agentiveM selves as parts of the motor control system and the boundaryB self as the capacity to form and integrated map of the body. I point to the delusion of thought broadcast as a possible source of evidence for future research on the boundaryM self.

De Vignemont argues that the sense of ownership comes from the localization of bodily sensation on a map of the body that is part of the body schema. This model should be taken as a model of the sense of embodiment. I argue that the body schema lacks the theoretical resources needed to explain this phenomenology. Furthermore, there is some reason to think that a deficient sense of embodiment is not associated with a deficient body schema. The data de Vignemont uses to argue that the body image does not underlie the sense of embodiment does not rule out the possibility that part of the body image I call 'offline representations' underlies the sense of embodiment. An alternative model of the sense of embodiment in terms of offline representations of the body is presented.

I offer a new metacognitive account of the feeling of agency over bodily actions. On this model the feeling of agency is the metacognitive monitoring of two cues: i) smoothness of action: done via monitoring the output of the comparison between actual and predicted sensory consequences of action and ii) action outcome: done via monitoring the outcome of action and its success relative to a prior intention. Previous research has shown that the comparator model offers a powerful explanation of the feeling of agency. However, within the literature there is a growing sense of unease with the model; a consensus seems to be building that the model is not up to the task of explaining all of the new discoveries made regarding the feeling of agency since its inception. Most problematically there are paradigms which deeply challenge the comparator model by suggesting that a weak feeling of agency can be elicited even when no motor prediction is formed. The new account offered here inherits the explanatory power of the comparator model whilst avoiding this problem.

The rubber hand illusion (RHI) is the experience of an artificial body part as being a real body part and the experience of touch coming from that artificial body part. An explanation of this illusion would take significant steps towards explaining the experience of embodiment in one’s own body. I present a new cognitive model to explain the RHI. I argue that the sense of embodiment arises when an on-line representation of the candidate body part is represented as matching an off-line prototype representation of what one’s body is usually like. The cause of the sense of embodiment in the model body part only partially overlaps with the causes of proprioceptive drift, which commonly accompanies the RHI, and so is compatible with observed dissociations between the illusion and proprioceptive drift. The distinguishing features of this model are the off-line body representation, and the process of matching an on-line model to an off-line model, both of which are to be understood in terms of a conceptual space. Key Words: Rubber Hand Illusion; RHI; Sense of Embodiment; Self Consciousness; Body Experience.

Contemporary theories of self-consciousness typically begin by dividing experiences of the self into types, each requiring separate explanation. The stereotypical case of an out of body experience may be seen to suggest a distinction between the sense of oneself as an experiencing subject, a mental entity, and a sense of oneself as an embodied person, a bodily entity. Point of view, in the sense of the place from which the subject seems to experience the world, in this case is tied to the sense of oneself as a mental entity and seems to be the ‘real’ self. Closer reading of reports, however, suggests a substantially more complicated picture. For example, the ‘real’ self that is experienced as separate from the body in an OBE is not necessarily experienced as disembodied. Subjects may experience themselves as having two bodies. In cases classed as heautoscopy there is considerable confusion regarding the apparent location of the experiencing subject; is it the ‘real mind’ in the body I seem to be looking out from, or is it in the body that I see? This suggests that visual point of view can dissociate from the experience of one’s own “real mind” or experience of self-identification. I provide a tripartite distinction between the sense of ownership, the sense of embodiment and the sense of subjectivity to better describe these experiences. The phenomenology of OBEs suggests that there are three distinct forms of self-consciousness which need to be explained.

I thank Tsakiris and Fotopoulou for their insightful commentary on my target article. In particular I welcome the opportunity to revisit how the online /offline representation of the body distinction is drawn. Tsakiris and Fotopoulou raise three major points of concern with my model. First they argue that the sense of embodiment is not sufficient for self recognition. Second they show that the relationship between online and offline representations of the body cannot be the simple ‘serial construction’ relationship I advocate in the target article. Third they claim that my model makes a false prediction. I agree with the first two lines of criticism. As to the first I will clarify and tone down the claims made about the role of the sense of embodiment in self recognition tasks. However, I will argue that the sense of embodiment is measured in van den Bos and Jeannerod’s study. I strongly welcome the second line of criticism Tsakiris and Fotopoulou offer. I will add some reasons to agree that the ‘serial construction’ account of the relationship between online and offline representations cannot be true. I maintain, however, that this does not affect the central thesis of target article, namely that it is an offline representation of the body that underlies the sense of embodiment. Finally, I will defend the model by arguing that it does not make the false prediction Tsakiris and Fotopoulou attribute to it

The sense of agency, that is the sense that one is the agent of one’s bodily actions, is one component of our self-consciousness. Recently, Wegner and colleagues have developed a model of the causal history of this sense. Their model takes it that the sense of agency is elicited for an action when one infers that one or other of one’s mental states caused that action. In their terms, the sense of agency is elicited by the inference to apparent mental state causation. Here, I argue that this model is inconsistent with data from developmental psychology that suggests children can identify the agent behind an action without being capable of understanding the relationship between their intentions and actions. Furthermore, I argue that this model is inconsistent with the preserved sense of agency in autism. In general, the problem is that there are cases where subjects can experience themselves as the agent behind their actions despite lacking the resources to make the inference to apparent mental state causation.

I compare Frith and colleagues’ influential comparator account of how the sense of agency is elicited to the multifactorial weighting model advocated by Synofzik and colleagues. I defend the comparator model from the common objection that the actual sensory consequences of action are not needed to elicit the sense of agency. I examine the comparator model’s ability to explain the performance of healthy subjects and those suffering from delusions of alien control on various self-attribution tasks. It transpires that the comparator model needs case-by-case adjustment to deal with problematic data. In response to this, the multifactorial weighting model of Synofzik and colleagues is introduced. Although this model is incomplete, it is more naturally constrained by the cases that are problematic for the comparator model. However, this model may be untestable. I conclude that currently the comparator model approach has stronger support than the multifactorial weighting model approach.

The sense of agency over bodily actions is the feeling that one is the agent of one's actions. In this paper I examine the prospects of Frith and colleagues' influential comparator account of how the sense of agency over one's bodily actions is elicited, in comparison to the multifactorial weighting model advocated by Synofzik and colleagues in response to some problems with this account. I examine two problems for the comparator model. I consider the common objection that the actual sensory consequences of action aren't needed to elicit the sense of agency with a look at the data which most strongly suggests this, namely the preserved sense of agency over phantom limb movements. I consider a problem for the comparator model in the behaviour of normal subjects placed in unusual circumstances, in particular I consider the 'wheel of fortune' studies which some take to be problematic for the comparator model. I argue that neither of these objections are devastating for the comparator model and that the comparator model plus some plausible assumptions can explain these data. However, these assumptions are not part of the original comparator model. In the end we get a version of the comparator model modified to deal with problematic cases in a manner that could be seen as somewhat ad hoc. To deal with this the multifactorial weighting model of Synofzik and colleagues is introduced. Although this model is incomplete a single version can be offered which is naturally constrained by the cases which are problematic for the comparator model. However, it is not clear what, if anything, could count as evidence against the multifactorial weighting model. Despite being generated with the data in mind it may be untestable. I conclude that currently the comparator model has stronger support than the multifactorial weighting model.

The sense of embodiment is vital for self recognition. An examination of anosognosia for hemiplegia—the inability to recognise that one is paralysed down one side of one’s body—suggests the existence of ‘online’ and ‘offline’ representations of the body. Online representations of the body are representations of the body as it is currently, are newly constructed moment by moment and are directly “plugged into” current perception of the body. In contrast, offline representations of the body are representations of what the body is usually like, are relatively stable and are constructed from online representations. This distinction is supported by an analysis of phantom limb—the feeling that an amputated limb is still present—phenomena. Initially it seems that the sense of embodiment may arise from either of these types of representation; however, an integrated representation of the body seems to be required. It is suggested information from vision and emotions is involved in generating these representations. A lack of access to online representations of the body does not necessarily lead to a loss in the sense of embodiment. An integrated offline representation of the body could account for the sense of embodiment and perform the functions attributed to this sense.

In this paper we try to diagnose one reason why the debate regarding the Hard Problem of consciousness inevitably leads to a stalemate: namely that the characterisation of consciousness assumed by the Hard Problem is unjustified and probably unjustifiable. Following Dennett : 4–6, 1996, Cognition 79:221–237, 2001, J Conscious Stud 19:86, 2012) and Churchland :402–408, 1996, Brainwise: studies in neurophilosophy. MIT Press, Cambridge, MA, 2002), we argue that there is in fact no non-question begging argument for the claim that consciousness is a uniquely Hard Phenomenon. That is; there is no non-question begging argument for the claim that consciousness is necessarily in explicable in terms of the structure and function of mental states. Unfortunately the debate has not moved on because the majority of materialists feel the pull of the at least one of, what we call, the ‘key’ intuitions that supposedly support dualism and the existence of a Hard Phenomenon and so try to accommodate them rather than denying them. Although this a possible response to the intuitions it tends to mask the fact that there is in fact no argument for the existence of a Hard Phenomenon. So we end up participating in our own hornswoggling :402–408, 1996) and chasing our tails trying to answer a question we should in fact ignore. We have no reason to think there is a Hard Problem of consciousness because we have no reason to think the Hard Phenomenon exists.

Introduction. The sense of agency over thoughts is the experience of oneself qua agent of mental action. Those suffering certain psychotic symptoms are thought to have a deficient sense of agency. Here I seek to explain this sense of agency in terms of metacognition. Method. I start with the proposal that the sense of agency is elicited by metacognitive monitoring representations that are used in the intentional inhibition of thoughts. I apply this model to verbal hallucinations and the like and examine the plausibility of this model explaining deficits associated with these symptoms. Results. By tying the sense of agency to metacognitive inhibition I propose that the loss of a sense of agency in certain psychotic symptoms is accompanied by a particular deficit in the patient’s ability to control their own thinking. This is consistent with the experiences of those at high risk of developing hallucinations, who report more intrusive thoughts than controls. The model I present is able to explain why those at risk of developing verbal hallucinations and those suffering from verbal hallucinations have deficits in the intentional inhibition of thought. I defend this account from a possible objection by distinguishing the form of the intentional inhibition deficit displayed by those suffering verbal hallucination from that displayed by those suffering from orbital-frontal cortex lesions and posttraumatic stress disorder. Conclusion. A plausible hypothesis is that the sense of agency over thoughts is elicited by the metacognitive monitoring representation used to intentionally inhibit.

“Spousal revenge” killers murder their child apparently out of a desire to cause harm to their ex-partner, the child’s other parent. Standard explanations of these killings fail to provide an adequate solution to what I call the problem of spousal revenge filicide. This is the problem of how a killer comes to take their rage at their former partner out on their own child and how that child can be dehumanized to the point of murder. Although the dehumanization of the victim is acknowledged to occur, why it occurs is not well understood. Here, I offer an hypothesis that the killer fails to represent their child as a moral subject with a mind of their own. This is due to a deficit in the killer’s capacity for person perception which is, by hypothesis, pathological. As such, the killer experiences the child as an object, rather than a person, which is of significant emotional value to the other parent. The specificity of this disorder explains why the ex-partner themselves is not targeted, and it explains how the killer is able to understand that killing the child will harm the other parent.