Online research in philosophy

Ned BlockÕs influential distinction between phenomenal and access consciousness has become a staple of current discussions of consciousness. It is not often noted, however, that his distinction tacitly embodies unargued theoretical assumptions that favor some theoretical treatments at the expense of others. This is equally so for his less widely discussed distinction between phenomenal consciousness and what he calls reflexive consciousness. I argue that the distinction between phenomenal and access consciousness, as Block draws it, is untenable. Though mental states that have qualitative character plainly differ from those with no mental qualities, a mental stateÕs being conscious is the same property for both kinds of mental state. For one thing, as Block describes access consciousness, that notion does not pick out any property that we intuitively count as a mental stateÕs being conscious. But the deeper problem is that BlockÕs notion of phenomenal consciousness, or phenomenality, is ambiguous as between two very different mental properties. The failure to distinguish these results in the begging of important theoretical questions. Once the two kinds of phenomenality have been distinguished, the way is clear to explain qualitative consciousness by appeal to a model such as the higher-order-thought hypothesis. Ó 2002 Elsevier Science (USA). All rights reserved.

The value of resting electroencephalogram (EEG) in revealing neural constitutes of consciousness (NCC) was examined. We quantified the dynamic repertoire, duration and oscillatory type of EEG microstates in eyes-closed rest in relation to the degree of expression of clinical self-consciousness. For NCC a model was suggested that contrasted normal, severely disturbed state of consciousness and state without consciousness. Patients with disorders of consciousness were used. Results suggested that the repertoire, duration and oscillatory type of EEG microstates in resting condition quantitatively related to the level of consciousness expression in brain-damaged patients and healthy-conscious subjects. Specifically, results demonstrated that (a) decreased number of EEG microstate types was associated with altered states of consciousness, (b) unawareness was associated with the lack of diversity in EEG alpha-rhythmic microstates, and (c) the probability for the occurrence and duration of delta-, theta- and slow-alpha-rhythmic microstates were associated with unawareness, whereas the probability for the occurrence and duration of fast-alpha-rhythmic microstates were associated with consciousness. In conclusion, resting EEG has a potential value in revealing NCC. This work may have implications for clinical care and medical–legal decisions in patients with disorders of consciousness.

Following coma, some patients will recover wakefulness without signs of consciousness (only showing reflex movements, i.e., the vegetative state) or may show non-reflex movements but remain without functional communication (i.e., the minimally conscious state). Currently, there remains a high rate of misdiagnosis of the vegetative state (Schnakers et. al. BMC Neurol, 9:35, 8) and the clinical and electrophysiological markers of outcome from the vegetative and minimally conscious states remain unsatisfactory. This should incite clinicians to use multimodal assessment to detect objective signs of consciousness and validate para-clinical prognostic markers in these challenging patients. This review will focus on advanced magnetic resonance imaging (MRI) techniques such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI (fMRI studies in both “activation” and “resting state” conditions) that were recently introduced in the assessment of patients with..

This article defends two theses: that a mental state is conscious if and only if it has phenomenal character, i.e., if and only if there is something it is like for the subject to be in that state, and that all state consciousness involves self-consciousness, in the sense that a mental state is conscious if and only if its possessor is, in some suitable way, conscious of being in it. Though neither of these theses is novel, there is a dearth of direct arguments for them in the scholarly literature and the relationship between them has so far gone underrecognized. This article attempts to remedy this lack, advancing the claim that if all conscious states have phenomenal character, then all state consciousness involves self-consciousness.

Some patients awaken from their coma but only show reflex motor activity. This condition of wakeful (eyes open) unawareness is called the vegetative state. In 2002, a new clinical entity coined ‘‘minimally conscious state’’ defined patients who show more than reflex responsiveness but remain unable to communicate their thoughts and feelings. Emergence from the minimally conscious state is defined by functional recovery of verbal or nonverbal communication.1 Our empirical medical definitions aim to propose clearcut borders separating disorders of consciousness such as coma, vegetative state and minimally conscious state but clinical reality shows that these boundaries can often be fuzzy (fig 1). Recent clinical, electrophysiological and neuroimaging studies are shedding light on these challenging limits of consciousness encountered following severe acute brain damage. At the patient’s bedside, it is very challenging to differentiate reflex or automatic motor behaviour from movements indicating signs of consciousness, and hence some minimally conscious patients might be misdiagnosed as being vegetative. For some motor responses (eg, blinking to visual threat, brief fixation, normal flexion response to pain, etc) it remains unclear whether they truly are voluntary or willed because we lack convincing scientific evidence. We also lack consensus on how to practically assess some of these behavioural responses. For example, there is no agreement on what stimulus to employ in the assessment of visual pursuit movements— often one of the first clinical signs heralding the transition from the vegetative to the minimally conscious state. Vanhaudenhuyse and colleagues2 recently studied visual pursuit in 51 post-comatose patients comparing eye tracking of a moving object, person or mirror. It was shown that more..

Disorders of consciousness include coma, the vegetative state and the minimally conscious state. Such patients are often regarded as unconscious. This has consequences for end of life decisions for these patients: it is much easier to justify withdrawing life support for unconscious than conscious patients. Recent brain imaging research has however suggested that some patients may in fact be conscious.

Recent progress in neurosciences has improved our understanding of chronic disorders of consciousness. One example of this advancement is the emergence of the new diagnostic category of minimally conscious state (MCS). The central characteristic of MCS is impaired consciousness. Though the phenomenon now referred to as MCS pre-existed its inclusion in diagnostic classifications, the current medical ethical concepts mainly apply to patients with normal consciousness and to non-conscious patients. Accordingly, how we morally should stand with persons in minimally conscious state remains unclear. In this paper, I examine whether the notion of human dignity could provide us with guidance with the moral difficulties MCS gives rise to. More precisely, I focus on the question of whether we are justified in holding that persons in minimally conscious state possess human dignity.

I begin by considering Ned Block's widely accepted distinction between phenomenal and access consciousness. I argue that on Block's official characterization a mental state's being access conscious is not a way the state's being conscious in any intuitive sense; that if phenomenal consciousness itself corresponds to an intuitive way of a state's being conscious, it literally implies access consciousness; and that Block misconstrues the theoretical significance of the commonsense distinction. These considerations point to the view that mental states' being conscious consists in their being accompanied by occurrent, assertoric thoughts to the effect that one is in the state in question: what I have elsewhere called higher- order thoughts (HOTs). After outlining the model, I sketch theoretical advantages having to do with introspective consciousness, the relationship between consciousness and speech, and the metacognitive phenomenon known as feeling-of-knowing judgments. I conclude by showing that the HOT model does justice to phenomenal consciousness: Sensory states are not all conscious, and HOTS explain why there is something it is like to be in those which are.

Consciousness in experimental subjects is typically inferred from reports and other forms of voluntary behaviour. A wealth of everyday experience confirms that healthy subjects do not ordinarily behave in these ways unless they are conscious. Investigation of consciousness in vegetative state patients has been based on the search for neural evidence that such broad functional capacities are preserved in some vegetative state patients. We call this the standard approach. To date, the results of the standard approach have suggested that some vegetative state patients might indeed be conscious, although they fall short of being demonstrative. The fact that some vegetative state patients show evidence of consciousness according to the standard approach is remarkable, for the standard approach to consciousness is rather conservative, and leaves open the pressing question of how to ascertain whether patients who fail such tests are conscious or not. We argue for a cluster-based ‘natural kind’ methodology that is adequate to that task, both as a replacement for the approach that currently informs research into the presence or absence of consciousness in vegetative state patients and as a methodology for the science of consciousness more generally.

Neuroimaging studies of brain-damaged patients diagnosed as in the vegetative state suggest that the patients might be conscious. This might seem to raise no new ethical questions given that in related disputes both sides agree that evidence for consciousness gives strong reason to preserve life. We question this assumption. We clarify the widely held but obscure principle that consciousness is morally significant. It is hard to apply this principle to difficult cases given that philosophers of mind distinguish between a range of notions of consciousness and that is unclear which of these is assumed by the principle. We suggest that the morally relevant notion is that of phenomenal consciousness and then use our analysis to interpret cases of brain damage. We argue that enjoyment of consciousness might actually give stronger moral reasons not to preserve a patient's life and, indeed, that these might be stronger when patients retain significant cognitive function.