Recently, the possibility of misrepresentation has resurfaced in the debate between higher-order thought theorists and their opponents. One new element in the debate has been the rare cases of Charles Bonnet syndrome , proposed as empirical evidence for misrepresentation as posited by the higher-order theories. In this article I will spell out the argument supposedly underlying the claim that the RCB cases are genuine empirical evidence of misrepresentation. I will then proceed to show that this argument relies (...) on a hidden premise. With this premise exposed the argument cannot support the notion of misrepresentation posited by higher-order theories. (shrink)

Based on recent insight into the thalamocortical system and its role in perception and conscious experience, a unified pathophysiological framework for hallucinations in neurological and psychiatric conditions is proposed, which integrates previously unrelated neurobiological and psychological findings. Gamma-frequency rhythms of discharge activity from thalamic and cortical neurons are facilitated by cholinergic arousal and resonate in networks of thalamocortical circuits, thereby transiently forming assemblies of coherent gamma oscillations under constraints of afferent sensory input and prefrontal attentional mechanisms. If perception is based (...) on synchronisation of intrinsic gamma activity in the thalamocortical system, then sensory input to specific thalamic nuclei may merely play a constraining role. Hallucinations can be regarded as underconstrained perceptions that arise when the impact of sensory input on activation of thalamocortical circuits and synchronisation of thalamocortical gamma activity is reduced. In conditions that are accompanied by hallucinations, factors such as cortical hyperexcitability, cortical attentional mechanisms, hyperarousal, increased noise in specific thalamic nuclei, and random sensory input to specific thalamic nuclei may, to a varying degree, contribute to underconstrained activation of thalamocortical circuits. The reticular thalamic nucleus plays an important role in suppressing random activity of relay cells in specific thalamic nuclei, and its dysfunction may be implicated in the biological vulnerability to hallucinations in schizophrenia. Combined with general activation during cholinergic arousal, this leads to excessive disinhibition in specific thalamic nuclei, which may allow cortical attentional mechanisms to recruit thalamic relay cells into resonant assemblies of gamma oscillations, regardless of their actual sensory input, thereby producing an underconstrained perceptual experience. Key Words: Charles Bonnet syndrome; gamma oscillations; hallucinations; late paraphrenia; Lewy body dementia; perception; schizophrenia; thalamocortical system. (shrink)

When you hallucinate an object, you are not in the normal sort of concurrent causal sensory interaction with that object. It's standardly further inferred that the hallucinated object does not actually exist. But the lack of normal concurrent causal sensory interaction does not imply that there does not exist an object that is hallucinated. It might be a past‐perceived object. In this paper, I argue that this claim holds for at least some interesting cases of hallucination. Hallucinations generated by misleading (...) cues (e.g. ‘seeing’ Kanizsa triangles), hallucinations of Charles Bonnet Syndrome patients, and dreams are experiences of past‐perceived objects. (shrink)

According to a widespread view about the content of conscious experience (Peacocke, 1992; Siegel, 2007), an experience has content when it is accurate relative to a possible scenario. Suppose you saw a ripe tomato. Your visual experience would have content if what you saw looked exactly like a ripe tomato, be it a genuine tomato or an expertly designed wax copy of a tomato. I argue that this view cannot account for the content of a hallucination whose content is impossible. (...) A 95-year old patient seems to see small pumpkins and flowers coming out of her body (Rocha et al., 2012). Intuitively, the patient's hallucination has content. But the accuracy-conditions view has to classify the experience as devoid of content, because what the patient hallucinated is impossible – accurate to no possible scenario. On the concept of flower we possess, it is incoherent for flowers to erupt from under one's skin. This visual hallucination is a counterexample to the view that an experience is endowed with content only relative to its accuracy conditions. (shrink)

Neurological syndromes in which consciousness seems to malfunction, such as temporal lobe epilepsy, visual scotomas, Charles Bonnet syndrome, and synesthesia offer valuable clues about the normal functions of consciousness and ‘qualia’. An investigation into these syndromes reveals, we argue, that qualia are different from other brain states in that they possess three functional characteristics, which we state in the form of ‘three laws of qualia ’ based on a loose analogy with Newton’s three laws of classical mechanics. (...) First, they are irrevocable: I cannot simply decide to start seeing the sunset as green, or feel pain as if it were an itch; second, qualia do not always produce the same behaviour: given a set of qualia, we can choose from a potentially infinite set of possible behaviours to execute; and third, qualia endure in short-term memory, as opposed to non-conscious brain states involved in the on-line guidance of behaviour in real time. We suggest that qualia have evolved these and other attributes (e.g. they are ‘filled in’) because of their role in facilitating non-automatic, decision-based action. We also suggest that the apparent epistemic barrier to knowing what qualia another person is experiencing can be overcome simply by using a ‘bridge ’ of neurons; and we offer a hypothesis about the relation between qualia and one’s sense of self. (shrink)

Neurological syndromes in which consciousness seems to malfunction, such as temporal lobe epilepsy, visual scotomas, Charles Bonnet syndrome, and synesthesia offer valuable clues about the normal functions of consciousness and ‘qualia’. An investigation into these syndromes reveals, we argue, that qualia are different from other brain states in that they possess three functional characteristics, which we state in the form of ‘three laws of qualia’. First, they are irrevocable: I cannot simply decide to start seeing the sunset (...) as green, or feel pain as if it were an itch; second, qualia do not always produce the same behaviour: given a set of qualia, we can choose from a potentially infinite set of possible behaviours to execute; and third, qualia endure in short-term memory, as opposed to non-conscious brain states involved in the on-line guidance of behaviour in real time. We suggest that qualia have evolved these and other attributes because of their role in facilitating non-automatic, decision-based action. We also suggest that the apparent epistemic barrier to knowing what qualia another person is experiencing can be overcome by using a ‘bridge’ of neurons; and we offer a hypothesis about the relation between qualia and one's sense of self. (shrink)

There is tension between commonly held views concerning phenomenal imagery on the one hand and our first-person epistemic access to it on the other. This tension is evident in many individual issues and experiments in philosophy and psychology (e.g. inattentional and change blindness, the speckled hen, dream coloration, visual periphery). To dissolve it, we can give up either (i) that we lack full introspective access to the phenomenal properties of our imagistic experiences, or (ii) that phenomenal imagery is fully determined, (...) or (iii) that phenomenal imagery does not exist. Which option is preferable? I explore the feasibility of option (ii) in more details by distinguishing between di erent kinds of indeterminacy. One of the most often proclaimed versions of indeterminacy is tied to Representationalism. However, I argue that in this context, Representationalism appears to be the least satisfying option, for which I give ten reasons. By abduction, we should reject Representationalism in favour of (i) or (iii)—the most parsimonious option being eliminativism, and the most conservative being the rejection of privileged access. The decision between these two, however, should be made on a case-by-case basis, depending on which is most adequate given the data. I illustrate this with the comparison between visual agnosia and Charles-Bonnet-Syndrome. (shrink)

I argue that there are no plausible non-representational explanations of episodes of hallucination. To make the discussion more specific, I focus on visual hallucinations in Charles Bonnet syndrome. I claim that the character of such hallucinatory experiences cannot be explained away non-representationally, for they cannot be taken as simple failures of cognizing or as failures of contact with external reality—such failures being the only genuinely non-representational explanations of hallucinations and cognitive errors in general. I briefly introduce a (...) recent computational model of hallucination, which relies on generative models in the brain, and argue that the model is a prime example of a representational explanation referring to representational mechanisms. The notion of the representational mechanism is elucidated, and it is argued that hallucinations—and other kinds of representations—cannot be exorcised from the cognitive sciences. (shrink)

Weak phantasmata have a decisive and specifically transcendental function in our everyday perception. This paper provides several different arguments for this claim based on evidence from both empirical psychology and phenomenology.

I argue that there are no plausible non-representational explanations of episodes of hallucination. To make the discussion more specific, I focus on visual hallucinations in Charles Bonnet syndrome. I claim that the character of such hallucinatory experiences cannot be explained away non-representationally, for they cannot be taken as simple failures of cognizing or as failures of contact with external reality—such failures being the only genuinely non-representational explanations of hallucinations and cognitive errors in general. I briefly introduce a (...) recent computational model of hallucination, which relies on generative models in the brain, and argue that the model is a prime example of a representational explanation referring to representational mechanisms. The notion of the representational mechanism is elucidated, and it is argued that hallucinations—and other kinds of representations—cannot be exorcised from the cognitive sciences. (shrink)

The Oxford University Studies in the Enlightenment series, previously known as SVEC (Studies on Voltaire and the Eighteenth Century), has published over 500 peer-reviewed scholarly volumes since 1955 as part of the Voltaire Foundation at the University of Oxford. International in focus, Oxford University Studies in the Enlightenment volumes cover wide-ranging aspects of the eighteenth century and the Enlightenment, from gender studies to political theory, and from economics to visual arts and music, and are published in English or French.

In the course of the eighteenth century, understanding human cognitive life came to be construed as something to be explored in terms of the physiology of the sensory organs, the nerves, and the brain: a form of naturalization that effectively moved cognition out of the realm of philosophy as it had traditionally been understood. Bonnet's Analytical Essay on the Faculties of the Soul was at the forefront of these developments, and this is its first English translation. Drawing on his (...) earlier work in natural history -- he was the leading entomologist of his era -- he approaches problems of the nature of the mind via the physiology and anatomy of the brain and sensory systems. His approach is one of 'reverse engineering', starting from an organic statue without faculties, and investigating how it would need to be modified to produce a human being. Bonnet takes up a position that cuts across the standard understanding of the period as a clash between materialism and dualism. While his approach was rigorously naturalistic and physiological, this did not lead him to reject the notion of a soul. Instead, he argues that, in order to make sense of their sensory abilities, we need to attribute a soul to animals as well as human beings. At the same time, he argues that if personal immortality is to be possible, it can be conceived along the lines of insect metamorphosis, which shows how different biological forms can harbour a single identity.--dust jacket. (shrink)

In diesem Artikel geht es um die historische und konzeptuelle Entwicklung von Charles Bonnets (1720-1793) allgemeiner Systemtheorie organismischer Ordnung. Hierfür wird der Kontext von Bonnets Ansatz in Naturgeschichte und Philosophie rekonstruiert. Leitfaden zur Analyse von Bonnets Systemtheorie bildet das Problem der doppelten Verortung des Organischen: Zum einen unterscheiden sich organisierte Körper durch ihre Ordnungsform von allen nicht organisierten Körpern, und zum anderen reihen sie sich zusammen mit den nicht-organisierten Körpern in eine Stufenleiter der Wesen ein, die von den Elementen (...) bis zum Menschen reicht und Mineralien, Pflanzen und Tiere umfasst. Anhand dieser Problemstellung wird eine Interpretationsebene entwickelt, die es erlaubt, Bonnets Ansatz einer bestimmten Transformation zwischen klassischer Metaphysik und Naturgeschichte zuzuordnen. The article focuses on the historical and conceptual development of Charles Bonnet's (1720-1793) general system theory of organismic order. The context of Bonnet's work will be reconstructed in natural history and philosophy. The problem of the double position of organic bodies is central for the understanding of Bonnet's theory: On the one hand, organized bodies are different from all non-organized bodies, and on the other hand, organized and non-organized beings form a single scale of beings that reaches from the elements to minerals, plants, animals and humans. This problematic setting will be characterized as a specific transformation between classical metaphysics and natural history. (shrink)

Werner syndrome is a rare autosomal recessive disorder that mimics some of the characteristics of aging. The gene for this disorder has recently been identified as a helicase of the recQ subclass(1). Other phenotypically distinctive disorders caused by different helicase mutations include Bloom syndrome, Cockayne syndrome, xeroderma pigmentosum and trichothiodystrophy. Possible mechanisms by which helicases might produce the variable phenotypes are discussed. These include altered nucleotide excision repair and RNA polymerase II‐mediated transcription. The discovery of the helicase (...) defect in Werner syndrome provides a road map for future study of its unique pathogenesis and conceivable, but unproved, relationship to the aging process. (shrink)

In eighteenth-century French natural history, the notion of preformation was not only a model for a small preexisting embryo that gradually extended its shape through the influx of particles, but also for an order that coordinated the dynamic relation between organic parts. Preformation depended therefore also on a hidden order behind the continuity of visible forms. Louis Bourguet, Charles Bonnet, and Georges Cuvier distinguished three organizational levels: First, the synchronic or functional order of organic systems; second, the diachronic (...) order of the initiation of mechanical processes; and third, the hierarchical order that regulates the interaction of organic parts. In this essay, I reconstruct and compare the three organizational levels in the writings of Bourguet, Bonnet and Cuvier, relate their models of organic unity to the principle of perfection, and contrast these models with Georges Buffon's critique of system theories. (shrink)

In reflecting on the relation between early empiricist conceptions of the mind and more experimentally motivated materialist philosophies of mind in the mid-eighteenth century, I suggest that we take seriously the existence of what I shall call ‘phantom philosophical projects’. A canonical empiricist like Locke goes out of his way to state that their project to investigate and articulate the ‘logic of ideas’ is not a scientific project: “I shall not at present meddle with the Physical consideration of the Mind” (...) (Essay, I.i.2). An equally prominent thinker, Immanuel Kant, seems to make an elementary mistake, given such a clear statement, when he claims that Locke’s project was a “physiology of the understanding,” in the Preface to the A edition of the first Critique). A first question, then, would be: what is this physiology of the understanding, if it was not Locke’s project? Did anyone undertake such a project? If not, what would it have resembled? My second and related case comes out of a remark the Hieronymus Gaub makes in a letter to Charles Bonnet of 1761: criticizing materialist accounts of mind and mind-body relations such as La Mettrie’s, Gaub suggests that what is needed is a thorough study of the “mechanics of the soul,” and that Bonnet could write such a study. What is the mechanics of the soul, especially given that it is presented as a non-materialist project? To what extent does it resemble the purported “physiology of the understanding”? And more generally, what do both of these phantom projects have to do with a process we might describe as a ‘naturalization of the soul’? (shrink)

Syndromic surveillance uses new ways of gathering data to identify possible disease outbreaks. Because syndromic surveillance can be implemented to detect patterns before diseases are even identified, it poses novel problems for informed consent, patient privacy and confidentiality, and risks of stigmatization. This paper analyzes these ethical issues from the viewpoint of the patient as victim and vector. It concludes by pointing out that the new International Health Regulations fail to take full account of the ethical challenges raised by syndromic (...) surveillance. (shrink)

An examination of split-brain syndrome, and whether split-brain patients have two minds.

How does Locke contribute to the development of 18th-century projects for a science of the mind, even though he seems to reject or at least bracket off such an idea himself? Contrary to later understandings of empiricism, Locke goes out of his way to state that his project to investigate and articulate the ‘logic of ideas’ is not a scientific project: “I shall not at present meddle with the Physical consideration of the Mind” (Essay, I.i.2). Locke further specifies that this (...) means his analysis of mental processes will not engage with knowledge of the brain (e.g. in terms of corpuscles and animal spirits), even though he had been the student of Thomas Willis. Now, Kant seemed to make an elementary mistake, given such a clear statement on Locke’s part, when he claimed that Locke’s project was a “physiology of the understanding” (in the Preface to the A edition of the first Critique). One can ask of course what this physiology of the understanding was, and if it existed, in or out of the Lockean intellectual world (as I have sought to investigate in a 2016 paper). This leads me to inquire into the outcome of his empiricism for a scientific treatment of the mind, including in the sense of a ‘naturalization’ of the mind (with implications also for our understanding of empiricism: Anstey’s influential distinction between experimental and speculative philosophy does not seem useful here). Because if Kant made this charge, there were also many 18th-century thinkers who positively treated Locke as their great forerunner in psychology and related fields: Charles Bonnet and Joseph Priestley among them, just as some prominent physicians such as Cabanis claimed to be ‘finishing the job’ that Locke had started in, e.g. their materialist theories of the passions. What one might term ‘the Locke Problem’ here is: how can one reconcile empiricism and claims about cerebral processes, while seeking to remain a Lockean? Differently put, what is the process of naturalization, a naturalization of? (shrink)

Background and Purpose The decision to perform decompressive craniectomy for patients with malignant MCA syndrome can be ethically complex. We investigated factors that clinicians consider in this decision-making process. Methods A survey including clinical vignettes and attitudes questions surrounding the use of hemicraniectomy in malignant MCA syndrome was distributed to 203 neurosurgeons, neurologists, staff and residents, and nurses and allied health members specializing in the care of neurological patients. These were practicing health care providers situated in an urban (...) setting in Canada where access to health care is covered by national policy and is a human right. Results Eighty-eight participants responded to survey. All participants unanimously supported the procedure for young and healthy patients. Advanced age, the presence of aphasia, comorbid medical conditions, and poor baseline functional status were dominant factors associated with increasing reluctance to offer surgical decompression. Patients’ previously expressed wishes were also an important consideration. Eighty-six percent of respondents agreed that withholding surgery is ethically justified if the outcome is perceived as futile. Conclusions Health care providers use similar factors to determine if aggressive management is justified given anticipated burden on patient quality of life and extended impact on society. This convergence can be harnessed beneficially for the transparent communication of medical options in the ethically complex setting of decompressive hemicraniectomy post-stroke. (shrink)

The majority of the world’s population now lives an urban existence, spending as much as 95% of their lives indoors. The olfactory atmosphere in the built environment has been shown to exert a profound, if often unrecognized, influence over our mood and well-being. While the traditionally malodorous stench to be found indoors (i.e., prior to the invention of modern sanitation) has largely been eliminated in recent centuries, many of the outbreaks of sick-building syndrome that have been reported over the (...) last half century have been linked to the presence of a strange smell in the environment. At the same time, however, there is also growing evidence that consumer behavior can be manipulated by the presence of pleasant ambient odors, while various aromatherapy scents are said to improve our mood and well-being. This Anglophone review focuses primarily on indoor western urban developed spaces. Importantly, the olfactory ambience constitutes but one component of the multisensory atmosphere and ambient odors interact with the visual, auditory, and haptic aspects of the built environment. Surprisingly, the majority of published studies that have deliberately chosen to combine ambient scent with other sensory interventions, such as, for example, music, have failed to increase store sales, or to enhance people’s mood and/or well-being, as might have been expected. Such negative findings therefore stress the importance of considering multisensory congruency while, at the same time, also highlighting the potential dangers that may be associated with sensory overload when thinking about the effect of ambient smell on our well-being. (shrink)

Patient outcome after serious brain injury is highly variable. Following a period of coma, some patients recover while others progress into a vegetative state (unresponsive wakefulness syndrome) or minimally conscious state. In both cases, assessment is difficult and misdiagnosis may be as high as 43%. Recent advances in neuroimaging suggest a solution. Both functional magnetic resonance imaging and electroencephalography have been used to detect residual cognitive function in vegetative and minimally conscious patients. Neuroimaging may improve diagnosis and prognostication. These (...) techniques are beginning to be applied to comatose patients soon after injury. Evidence of preserved cognitive function may predict recovery, and this information would help families and health providers. Complex ethical issues arise due to the vulnerability of patients and families, difficulties interpreting negative results, restriction of communication to “yes” or “no” answers, and cost. We seek to investigate ethical issues in the use of neuroimaging in behaviorally nonresponsive patients who have suffered serious brain injury. The objectives of this research are to: (1) create an approach to capacity assessment using neuroimaging; (2) develop an ethics of welfare framework to guide considerations of quality of life; (3) explore the impact of neuroimaging on families; and, (4) analyze the ethics of the use of neuroimaging in comatose patients. (shrink)