Hallucination And Imagination

What are hallucinations? A common view in the philosophical literature is that hallucinations are degenerate kinds of perceptual experience. I argue instead that hallucinations are degenerate kinds of sensory imagination. As well as providing a good account of many actual cases of hallucination, the view that hallucination is a kind of imagination represents a promising account of hallucination from the perspective of a disjunctivist theory of perception like naïve realism. This is because it provides a way of giving a positive characterisation of hallucination—rather than characterising hallucinations in negative, relational, terms as mental events that are subjectively indistinguishable from veridical perceptual experiences.     

Hallucinations for disjunctivists

In this paper, I examine the so-called disjunctive views on hallucinations. I argue that neither of the options open to the disjunctivist is capable of accommodating basic phenomenological facts about hallucinatory experiences and the explanatory demands behind the classical argument from hallucination. A positive characterization of the hallucinatory case is not attractive to a disjunctivist once she is disposed to accept certain commonalities with veridical experiences. Negative disjunctivism glosses the hallucinatory disjunct in terms of indiscriminability. I will argue that this move either renounces to characterize phenomenally the hallucinatory experience or does not take seriously questions about why indiscriminability is possible in the phenomenal realm.     

“Hearing voices”: Auditory hallucinations as failure of top‐down control of bottom‐up perceptual processes

Auditory hallucination is a key characteristic of schizophrenia that seriously debilitates the patient, with consequences for social engagement with others. Hallucinatory experiences are also observed in healthy individuals in the general population who report “hearing voices” in the absence of an external acoustic input. A view on auditory hallucinations and “hearing voices” is presented that regards such phenomena as perceptual processes, originating from speech perception areas in the left temporal lobe. Healthy individuals “hearing voices” are, however, often aware that the experience comes from inner thought processes, which is not reported by hallucinating patients. A perceptual model can therefore, not alone explain the difference in the phenomenology of how the “voices heard” are attributed to either an inner or outer cause. An expanded model is thus presented which takes into account top‐down cognitive control, localized to prefrontal cortical areas, to inhibit and re‐attribute the perceptual mis‐representations. The expanded model is suggested to be empirically validated using a dichotic listening speech perception paradigm with instructions for top‐down control of attention focus to either the right or left side in auditory space. It is furthermore suggested to use fMRI to validate the temporal and frontal lobe neuronal correlates of the cognitive processes involved in auditory hallucinations.     

Perceptual Content Defended

Recently, the thesis that experience is fundamentally a matter of representing the world as being a certain way has been questioned by austere relationalists. I defend this thesis by developing a view of perceptual content that avoids their objections. I will argue that on a relational understanding of perceptual content, the fundamental insights of austere relationalism do not compete with perceptual experience being representational. As it will show that most objections to the thesis that experience has content apply only to accounts of perceptual content on which perceptual relations to the world play no explanatory role. With austere relationalists, I will argue that perceptual experience is fundamentally relational. But against austere relationalists, I will argue that it is fundamentally both relational and representational.     

A problem for rationalist responses to skepticism

Rationalism, my target, says that in order to have perceptual knowledge, such as that your hand is making a fist, you must “antecedently” (or “independently”) know that skeptical scenarios don’t obtain, such as the skeptical scenario that you are in the Matrix. I motivate the specific form of Rationalism shared by, among others, White (Philos Stud 131:525–557, 2006) and Wright (Proc Aristot Soc Suppl Vol 78:167–212, 2004), which credits us with warrant to believe (or “accept”, in Wright’s terms) that our senses are reliably veridical, where that warrant is one we enjoy by default, that is, without relying on any evidence or engaging in any positive argument. The problem with this form of Rationalism is that, even if you have default knowledge that your senses are reliable, this is not adequate to rule out every kind of skeptical scenario. The problem is created by one-off skeptical scenarios, scenarios that involve a highly reliable perceiver who, by a pure fluke, has a one-off, non-veridical experience. I claim you cannot infer that your present perceptual experience is veridical just on the basis of knowledge of your general reliability. More generally, if you infer that the present F is G, just on the basis of your knowledge that most Fs are Gs, this is what I call statistical inference, and, as I argue, statistical inference by itself does not generate knowledge. I defend this view of statistical inference against objections, including the objection that radical skepticism about our ordinary inductive knowledge will follow unless statistical inference generates knowledge.     

What is my evidence that here is a cup?

This paper is about Susanna Schellenberg's view on the explanatory role of perceptual experience. I raise a basic question about what the argument for her view might be. Then I develop two new problem cases: one involving “seamless transitions” between perception and hallucination and another involving the graded character of perceptual evidence and justification.     

Seeing absence

Intuitively, we often see absences. For example, if someone steals your laptop at a café, you may see its absence from your table. However, absence perception presents a paradox. On prevailing models of perception, we see only present objects and scenes (Marr, Gibson, Dretske). So, we cannot literally see something that is not present. This suggests that we never literally perceive absences; instead, we come to believe that something is absent cognitively on the basis of what we perceive. But this cognitive explanation does not do justice to the phenomenology. Many experiences of absence possess immediate, perceptual qualities. One may further argue that the ability to detect certain absences confers strong adaptive advantage and therefore must be as primitive and fundamental to humans as seeing positive things. I argue that we can literally see absences; in addition to representing objects, perception represents absences of objects. I present a model of seeing absence based on visual expectations and a visual matching process. The phenomenon of seeing absence can thus serve as an adequacy-test for a theory of perceptual content. If experiences of absence are possible, then we have another reason (following Siegel) to reject the view that perceptual content is restricted to colors and shapes. Furthermore, if the proposed account is correct, then we have grounds for dissociating seeing absence from other imagery-based phenomena termed “perceptual presence-in-absence” (Noë, Macpherson).     

The intuitive case for naïve realism

Naïve realism, the view that perceptual experiences are irreducible relations between subjects and external objects, has intuitive appeal, but this intuitive appeal is sometimes thought to be undermined by the possibility of certain kinds of hallucinations. In this paper, I present the intuitive case for naïve realism, and explain why this intuitive case is not undermined by the possibility of such hallucinations. Specifically, I present the intuitive case for naïve realism as arguing that the only way to make sense of the phenomenal character associated with perceptual experiences is by means of a naïve realist ontology. I then explain why this intuitive argument is not undermined by the possibility of hallucinatory experiences that possess the phenomenal character associated with perceptual experiences but, being hallucinations, do not have the ontological nature specified by naïve realism.     

In Defense of Relational Direct Realism

Abstract: According to proponents of relational direct realism, veridical perceptual experiences are irreducibly relational mental states that include as constituents perceived physical objects or intrinsic aspects of them. One consequence of the theory is the rejection of the causal theory of perception. This paper defends the relational theory against several objections recently developed by Paul Coates. He argues that the required experiential relation is incoherent and unmotivated. The argument that it is incoherent commits a fallacy. In reply to the argument that it is unmotivated, I suggest that the relational theorist's appeal to transparency provides sufficient motive and, when properly clarified, defeasibly justifies the theory as well. Coates also argues that rejection of the causal theory leaves relational theorists without any way of determining which object is perceived or of accommodating our scientific understanding of perceptual experiences as causally dependent on physical objects. I reply that relational theorists are able to provide the required explanations and discuss how the relational theory is consistent with this scientific understanding of perceptual experience.     

REPRESENTATIONALISM AND THE ARGUMENT FROM HALLUCINATION

Abstract: Representationalism is sometimes advertised as providing a novel response to the argument from hallucination, one that accepts the presence of a 'common factor' between veridical and hallucinatory experience without positing sensory intermediaries between the mind and the world. I argue that much of the attractiveness of representationalism stems from a failure in the literature to distinguish between two distinct possible versions of representationalism, what I call 'content-based representationalism' and 'vehicle-based representationalism'. Generically, representationalism appears to have a response to the argument from hallucination that avoids a commitment to qualia or sense-data. But once the distinction between content-based representationalism and vehicle-based representationalism is recognized, this response to the argument from hallucination fails.     

Fears as Conscious Perceivings

Peter Goldie has argued for the view that the intentionality of emotions is inseparable from their phenomenology (IPE), but certain criticisms have revealed his argument as problematic. I will argue that it is possible to address these problems, at least in the case of the emotion of fear, thereby vindicating IPE, by appeal to a Husserlian version of the perceptual account of emotions, centered on the idea that the contents of perceptual experiences are fulfillment conditions. Fulfillment means the achievement of a kind of immediate, or “full”, experience of an object or some of its aspects. In the case of visual perception, suppose you are looking at an apple. If you turn it around, you will find yourself in full view of its back side, which was previously anticipated “emptily”, fulfilling or disappointing (confirming or disconfirming) some of your anticipations in regard to it. On the Husserlian view, the success or failure of a visual perceptual experience consists in such fulfillments and disappointments. If we can provide an account of the intentionality of emotions along similar lines, it will necessarily involve the phenomenal contrast between fullness and emptiness, enabling us to support IPE.     

“Seeing Rain”: Integrating phenomenological and Bayesian predictive coding approaches to visual hallucinations and self-disturbances (Ichstörungen) in schizophrenia

We present a schizophrenia patient who reports “seeing rain” with attendant somatosensory features which separate him from his surroundings. Because visual/multimodal hallucinations are understudied in schizophrenia, we examine a case history to determine the role of these hallucinations in self-disturbances (Ichstörungen). Developed by the early Heidelberg School, self-disturbances comprise two components: 1. The self experiences its own automatic processing as alien to self in a split-off, “doubled-I.” 2. In “I-paralysis,” the disruption to automatic processing is now outside the self in omnipotent agents. Self-disturbances (as indicated by visual/multimodal hallucinations) involve impairment in the ability to predict moment-to-moment experiences in the ongoing perception-action cycle. The phenomenological approach to subjective experience of self-disturbances complements efforts to model psychosis using the computational framework of hierarchical predictive coding. We conclude that self-disturbances play an adaptive, compensatory role following the uncoupling of perception and action, and possibly, other low-level perceptual anomalies.     

On A. D. Smith’s constancy based defence of direct realism

This paper presents an argument against A D Smith’s Direct Realist theory of perception, which attempts to defend Direct Realism against the argument from illusion by appealing to conscious perceptual states that are structured by the perceptual constancies. Smith’s contention is that the immediate objects of perceptual awareness are characterised by these constancies, which removes any difficulty there may be in identifying them with the external, or normal, objects of awareness. It is here argued that Smith’s theory does not provide an adequate defence of Direct Realism because it does not adequately deal with the difficulties posed by the possibility of perceptual illusion. It is argued that there remain possible illusory experiences where the immediate objects of awareness, which in Smith’s account are those characterised by perceptual constancies, cannot be identified with the external objects of awareness, contrary to Direct Realism. A further argument is offered to extend this conclusion to all non-illusory cases, by adapting an argument of Smith’s own for the generalising step of the Argument from Illusion. The result is that Smith’s theory does not provide an adequate Direct Realist account of the possibility of perceptual illusion.     

Schizophrenia or Possession?

Schizophrenia is typically a life-long condition characterized by acute symptom exacerbations and widely varying degrees of functional disability. Some of its symptoms, such as delusions and hallucinations, produce great subjective psychological pain. The most common delusion types are as follows: “My feelings and movements are controlled by others in a certain way” and “They put thoughts in my head that are not mine.” Hallucinatory experiences are generally voices talking to the patient or among themselves. Hallucinations are a cardinal positive symptom of schizophrenia which deserves careful study in the hope it will give information about the pathophysiology of the disorder. We thought that many so-called hallucinations in schizophrenia are really illusions related to a real environmental stimulus. One approach to this hallucination problem is to consider the possibility of a demonic world. Demons are unseen creatures that are believed to exist in all major religions and have the power to possess humans and control their body. Demonic possession can manifest with a range of bizarre behaviors which could be interpreted as a number of different psychotic disorders with delusions and hallucinations. The hallucination in schizophrenia may therefore be an illusion—a false interpretation of a real sensory image formed by demons. A local faith healer in our region helps the patients with schizophrenia. His method of treatment seems to be successful because his patients become symptom free after 3 months. Therefore, it would be useful for medical professions to work together with faith healers to define better treatment pathways for schizophrenia.     

The Relativity Of Color

C. L. Hardin led a recent development in the philosophical literature on color in which research from visual science is used to argue that colors are not properties of physical objects, but rather are mental processes. I defend J. J. C. Smart's physicalism, which claims that colors are physical properties of objects, against this attack. Assuming that every object has a single veridical (that is, nonillusory) color, it seems that physicalism must give a specification of veridical color in terms natural to physics, independently of our interests. Hardin argues that since physicalism doesn't give us any such specification of veridical color, this view is false. However, this argument assumes a mistaken account of veridical color. I show physicalism can appeal to an alternative account, according to which veridical color is characterized in terms of favored conditions of perceptual access, independently of any specification of the physical nature of color.     

Husserl and externalism

It is argued that Husserl was an “externalist” in at least one sense. For it is argued that Husserl held that genuinely perceptual experiences—that is to say, experiences that are of some real object in the world—differ intrinsically, essentially and as a kind from any hallucinatory experiences. There is, therefore, no neutral “content” that such perceptual experiences share with hallucinations, differing from them only over whether some additional non-psychological condition holds or not. In short, it is argued that Husserl was a “disjunctivist”. In addition, it is argued that Husserl held that the individual object of any experience, perceptual or hallucinatory, is essential to and partly constitutive of that experience. The argument focuses on three aspects of Husserl’s thought: his account of intentional objects, his notion of horizon, and his account of reality.     

Analysis of the multidimensionality of hallucination-like experiences in clinical and nonclinical Spanish samples and their relation to clinical symptoms: implications for the model of continuity

Numerous studies have found that hallucinatory experiences occur in the general population. But to date, few studies have been conducted to compare clinical and nonclinical groups across a broad array of clinical symptoms that may co-occur with hallucinations. Likewise, hallucination-like experiences are measured as a multidimensional construct, with clinical and subclinical components related to vivid daydreams, intrusive thoughts, perceptual disturbance, and clinical hallucinatory experiences. Nevertheless, these individual subcomponents have not been examined across a broad spectrum of clinically disordered and nonclinical groups. The goal of the present study was to analyze the differences and similarities in the distribution of responses to hallucination-like experience in clinical and nonclinical populations and to determine the relation of these hallucination-like experiences with various clinical symptoms. These groups included patients with schizophrenia, non-psychotic clinically disordered patients, and a group of individuals with no psychiatric diagnoses. The results revealed that hallucination-like experiences are related to various clinical symptoms across diverse groups of individuals. Regression analysis found that the Psychoticism dimension of the Symptom Check List (SCL-90-R) was the most important predictor of hallucination-like experiences. Additionally, increased auditory and visual hallucination was the only subcomponent that differentiated schizophrenic patients from other groups. This distribution of responses in the dimensions of hallucination-like experiences suggests that not all the dimensions are characteristic of people hearing voices. Vivid daydreams, intrusive thoughts, and auditory distortions and visual perceptual distortions may represent a state of general vulnerability that does not denote a specific risk for clinical hallucinations. Overall, these results support the notion that hallucination-like experiences are closer to a quasi-continuum approach and that total scores on these scales explain a state of vulnerability to general perceptual disturbance.     

Justified vs. Warranted Perceptual Belief: Resisting Disjunctivism

In this paper I argue that McDowell's brand of disjunctivism about perceptual knowledge is ill-motivated. First, I present a reconstruction of one main motivation for disjunctivism, in the form of an argument that theories that posit a "highest common factor" between veridical and non-veridical experiences must be wrong. Then I show that the argument owes its plausibility to a failure to distinguish between justification and warrant (where "warrant" is understood as whatever has to be added to true belief to yield knowledge).     

Verbal hallucinations in normals,I: People who hear ‘voices’

Two studies are reported that describe the phenomena of verbal hallucinations in the general population and test two explanations of those reports. Subjects were 198 male and 387 female college students who completed a verbal hallucination questionnaire plus one or more additional questionnaires. We found that a large minority reported hallucinations and that nearly half reported having them at least once a month. The present data indicated that these reports were not related to four measures of social conformity. Neither were they related to measures of overt, or incipient, symptoms of psychopathology. We have concluded that the majority of these reports are generally veridical accounts of conscious experience in normal individuals.     

Making sense of the libertarian’s semantic claim about agential phenomenology

Libertarians about free will sometimes argue for their position on the grounds that our phenomenology of action is such that determinism would need to be false for it to be veridical. Many, however, have thought that it would be impossible for us to have an experience that is in contradiction with determinism, since this would require us to have perceptual experience of metaphysical facts. In this paper I show how the libertarian claim is possible. In particular, if experience depicts the world such that there is more than one physically possible future, then determinism would need to be false for that experience to be veridical. I show that we have experiences, or perceptual episodes, of this kind on the basis of recent work in the study of perception. Theorists in this area have argued that we have vision-for-action, and that what we visually perceive are not just objects but also possibilities for action. If we experience that it is possible that we ?, then we also experience that it is possible that we not ?. Furthermore, we probably experience more than one possibility for action at any one moment. I argue that these are physical possibilities, and therefore that we experience the world such that there is more than one physically possible future. So the libertarian claim about the semantics of agential phenomenology is highly plausible, even if this does not entail libertarianism.