Objective: The value of spontaneous EEG oscillations in distinguishing patients in vegetative and minimally conscious states was studied. Methods: We quantified dynamic repertoire of EEG oscillations in resting condition with closed eyes in patients in vegetative and minimally conscious states (VS and MCS). The exact composition of EEG oscillations was assessed by the probability-classification analysis of short-term EEG spectral patterns. Results: The probability of delta, theta and slow-alpha oscillations occurrence was smaller for patients in MCS than for VS. Additionally, only (...) patients in MCS demonstrated fast-alpha oscillation occurrence. Depending on the type and composition of EEG oscillations, the probability of their occurrence was either aetiology dependent or independent. The probability of EEG oscillations occurrence differentiated brain injuries with different aetiologies. Conclusions: Spontaneous EEG oscillations have a potential value in distinguishing patients in VS and MCS. Significance: This work may have implications for clinical care, rehabilitative programs and medical–legal decisions in patients with impaired consciousness states following coma due to acute brain injuries. (shrink)

This paper defends the idea that phenomenological approaches to self-consciousness can enrich the current analytic philosophy of perception, by showing how phenomenological discussions of minimal self-consciousness can enhance our understanding of the phenomenology of conscious perceptual experiences. As a case study, I investigate the nature of the relationship between naïve realism, a contemporary Anglophone theory of perception, and experiential minimalism (or, the ‘minimal self’ view), a pre-reflective model of self-consciousness originated in the Phenomenological tradition. I (...) argue that naïve realism is not only compatible with, but can be supplemented with experiential minimalism in a novel way. The suggestion is that there are reasons to combine naïve realism and experiential minimalism. My focus here will be on drawing a connection between the notion of minimal self and two core theoretical commitments of naïve realism, relationalism and transparency. (shrink)

How should we treat patients diagnosed as being in a persistent vegetative state (PVS) or minimally conscious state (MCS)? More specifically, should we treat them as having the full moral status of persons? Yes, or so we argue. First, we introduce the medical conditions of PVS, MCS, and the related conditions of Locked-in Syndrome and covert awareness. Second, we characterize the main argument for thinking diagnosed PVS patients are not persons. Third, we contend that this argument is defeated by mounting (...) empirical evidence for the considerable uncertainty of PVS diagnoses. Fourth, we characterize a new argument for PVS non-personhood suggested by Neil Levy and Julian Savulescu, one intended to accommodate the diagnostic uncertainty. According to this argument, even if diagnosed PVS patients are in fact MCS, it makes no difference because MCS patients are probably not persons either. Fifth, we challenge the new argument by assembling reasons for doubting the claim that MCS patients are not persons. The outcome is that it is fairly uncertain whether diagnosed PVS and MCS patients are persons or not. What should we do in light of this uncertainty? Sixth, we develop and support a guiding precautionary principle, which we call Precautionary Personhood. Finally, we apply the principle to the case of diagnosed PVS and MCS patients: we argue that given substantial uncertainty about their personhood we should go ahead and treat these patients as if they are persons. (shrink)

Cognitive neuroscientists are currently busy searching for the neural signatures of conscious experience. I shall argue that the notion of neural correlates of consciousness employed in much of this work is subject to two very different interpretations depending on how one understands the relation between the concepts of “state consciousness” and “creature consciousness”. Localist theories treat the neural correlates of creature consciousness as a kind of background condition that must be in place in order for the (...) brain to realise particular conscious experiences. Holists on the other hand take the neural correlates of creature consciousness to be a part of the core realiser of a particular conscious experience. My aim in this paper will be threefold. First I argue we should understand creature consciousness as a property of those creatures that have a minimal sense of self. Given this conception of creature consciousness I argue that the localist position is untenable: creature consciousness cannot simply be a background condition. Finally I argue that the minimal sense of self is a consequence of the temporal structure of consciousness. It follows that any theory of NCCs must explain how experiences with a complex temporal structure can be implemented in neural processing. (shrink)

Quite a few recent models are rapidly introducing new concepts describing different levels of consciousness. This situation is getting confusing because some theorists formulate their models without making reference to existing views, redundantly adding complexity to an already difficult problem. In this paper, I present and compare nine neurocognitive models to highlight points of convergence and divergence. Two aspects of consciousness seem especially important: perception of self in time and complexity of self-representations. To this I add frequency of (...) self-focus, amount of self-related information, and accuracy of self-knowledge. Overall, I conclude that many novel concepts (e.g., reflective, primary, core, extended, recursive, and minimal consciousness) are useful in helping us distinguish between delicate variations in consciousness and in clarifying theoretical issues that have been intensely debated in the scientific literature—e.g., consciousness in relation to mirror self-recognition and language. Ó 2005 Elsevier Inc. All rights reserved. (shrink)

Quite a few recent models are rapidly introducing new concepts describing different levels of consciousness. This situ- ation is getting confusing because some theorists formulate their models without making reference to existing views, redun- dantly adding complexity to an already difficult problem. In this paper, I present and compare nine neurocognitive models to highlight points of convergence and divergence. Two aspects of consciousness seem especially important: perception of self in time and complexity of self-representations. To this I add (...) frequency of self-focus, amount of self-related informa- tion, and accuracy of self-knowledge. Overall, I conclude that many novel concepts (e.g., reflective, primary, core, extend- ed, recursive, and minimal consciousness) are useful in helping us distinguish between delicate variations in consciousness and in clarifying theoretical issues that have been intensely debated in the scientific literature—e.g., consciousness in rela- tion to mirror self-recognition and language. (shrink)

Wijdicks and colleagues1 recently presented the Full Outline of UnResponsiveness (FOUR) scale as an alternative to the Glasgow Coma Scale (GCS)2 in the evaluation of consciousness in severely brain-damaged patients. They studied 120 patients in an intensive care setting (mainly neuro-intensive care) and claimed that “the FOUR score detects a locked-in syndrome, as well as the presence of a vegetative state.”1 We fully agree that the FOUR is advantageous in identifying locked-in patients given that it specifically tests for eye (...) movements or blinking on command. This is welcomed given that misdiagnosis of the locked-in syndrome has been shown to occur in more than half of the cases (see Laureys and colleagues3 for review). As for the diagnosis of the vegetative state, the scale explicitly tests for visual pursuit, and hence can disentangle the vegetative state from the minimally conscious state (MCS). The diagnostic criteria for MCS have been proposed4 only recently, but Wijdicks and colleagues1 do not mention the existence of this clinical entity in their article. As for the vegetative state, MCS can be encountered in the acute or subacute setting as a transitional state on the way to further recovery, or it can be a more chronic or even permanent condition. The MCS refers to patients showing inconsistent, albeit clearly discernible, minimal behavioral evidence of consciousness (eg, localization of noxious stimuli, eye fixation or tracking, reproducible movement to command, or nonfunctional verbalization).4 The FOUR scale does not test for all of the behavioral criteria required to diagnose MCS.4 It is known from the literature (see Majerus and colleagues5 for review) that about a third of patients diagnosed with vegetative state are actually in MCS, and this misdiagnosis can lead to major clinical, therapeutic, and ethical consequences. We tested the ability of the newly proposed FOUR scale to correctly diagnose the vegetative state in an acute (intensive care and neurology ward) and chronic (neurorehabilitation) setting.. (shrink)

Background: Patients in a vegetative state pose problems in diagnosis, prognosis and treatment. Currently, no prognostic markers predict the chance of recovery, which has serious consequences, especially in end-of-life decision-making. Objective: We aimed to assess an objective measurement of prognosis using advanced electroencephalography (EEG). Methods: EEG data (19 channels) were collected in 14 patients who were diagnosed to be persistently vegetative based on repeated clinical evaluations at 3 months following brain damage. EEG structure parameters (amplitude, duration and variability within quasi-stationary (...) segments, as well as the spatial synchrony between such segments and the strength of this synchrony) were used to predict recovery of consciousness 3 months later. Results: The number and strength of cortical functional connections between EEG segments were higher in patients who recovered consciousness (P < .05 – P < .001) compared with those who did not recover. Linear regression analysis confirms that EEG structure parameters are capable of predicting (P = .0025) recovery of consciousness 6 months post-injury, whereas the same analysis failed to significantly predict patient outcome based on aspects of their clinical history alone (P = .629) or conventional EEG spectrum power (P = .473). Conclusions: The result of this preliminary study demonstrates that structural strategy of EEG analysis is better suited for providing prognosis of consciousness recovery than existing methods of clinical assessment and of conventional EEG. Our results may be a starting point for developing reliable prognosticators in patients who are in vegetative state, with the potential to improve their day-to-day management, quality of life, and access to early interventions. (shrink)

How, if at all, consciousness can be part of the physical universe remains a baffling problem. This article outlines a new, developing philosophical theory of how it could do so, and offers a preliminary mathematical formulation of a physical grounding for key aspects of the theory. Because the philosophical side has radical elements, so does the physical-theory side. The philosophical side is radical, first, in proposing that the productivity or dynamism in the universe that many believe to be responsible (...) for its systematic regularities is actually itself a physical constituent of the universe, along with more familiar entities. Indeed, it proposes that instances of dynamism can themselves take part in physical interactions with other entities, this interaction then being “meta-dynamism” (a type of meta-causation). Secondly, the theory is radical, and unique, in arguing that consciousness is necessarily partly constituted of meta-dynamic auto-sensitivity, in other words it must react via meta-dynamism to its own dynamism, and also in conjecturing that some specific form of this sensitivity is sufficient for and indeed constitutive of consciousness. The article proposes a way for physical laws to be modified to accommodate meta-dynamism, via the radical step of including elements that explicitly refer to dynamism itself. Additionally, laws become, explicitly, temporally non-local in referring directly to quantity values holding at times prior to a given instant of application of the law. The approach therefore implicitly brings in considerations about what information determines states. Because of the temporal non-locality, and also because of the deep connections between dynamism and time-flow, the approach also implicitly connects to the topic of entropy insofar as this is related to time. (shrink)

The concept of futility is sometimes regarded as a cloak for medical paternalism in that it rolls together medical and value judgments. Often, despite attempts to disambiguate the concept, that is true and it can be applied in such a way as to marginalize the real interests of a patient. I suggest we replace it with a conceptual toolkit that includes physiological futility, substantial benefit (SB), and the risk of unacceptable badness (RUB) in that these concepts allow us to articulate (...) what is at stake in ethical judgments where outcomes are crucial in determining what should be done. (shrink)

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. (shrink)

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. (shrink)

In this article, I consider whether the advance directive of a person in minimally conscious state ought to be adhered to when its prescriptions conflict with her current wishes. I argue that an advance directive can have moral significance after its issuer has succumbed to minimally conscious state. I also defend the view that the patient can still have a significant degree of autonomy. Consequently, I conclude that her advance directive ought not to be applied. Then I briefly assess whether (...) considerations pertaining to respecting the patient's autonomy could still require obedience to the desire expressed in her advance directive and arrive at a negative answer. (shrink)

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.. (shrink)

This short comment on the Court of Protection decision in W v M draws attention to the primacy the judge gave to the preservation of life and discusses the relative lack of weight accorded to M's previously expressed views.

In a recent book, Neil Levy argues that culpable action – action for which we are morally responsible – is necessarily produced by states of which we are consciously aware. However, criminal defendants are routinely held responsible for criminal harm caused by states of which they are not conscious in Levy’s sense. In this chapter I argue that cases of negligent criminal harm indicate that Levy’s claim that moral responsibility requires synchronic conscious awareness of the moral significance of an act (...) is too strict, and that tracing conditions cannot be successfully used to bolster Levy’s account. Instead, current legal practices indicate that criminal responsibility requires the capacity for diachronic agency and self-control, not synchronic conscious control. (shrink)

The paper argues that Zahavi’s defence of the self as an experiential dimension, i.e. “identified with the first-person givenness of experiential phenomena”, and of the notion of a pre-reflective minimal core self relies on an unwarranted assumption. It is assumed that awareness of the phenomenal mode of experiences of objects, i.e. what the object “feels” like for the experiencer, is comparable with, indeed entails, first-person givenness of experience. In consequence both the arguments concerning the foundational role of the (...) pre-reflective minimal core self and the explanation of the unity and identity of the self through time give rise to intractable problems. (shrink)

The proposal that probabilistic inference and unconscious hypothesis testing are central to information processing in the brain has been steadily gaining ground in cognitive neuroscience and associated fields. One popular version of this proposal is the new theoretical framework of predictive processing or prediction error minimization, which couples unconscious hypothesis testing with the idea of ‘active inference’ and claims to offer a unified account of perception and action. Here we will consider one outstanding issue that still looms large at the (...) core of the PEM framework: the lack of a clear criterion for distinguishing conscious states from unconscious ones. In order to fulfill the promise of becoming a unifying framework for describing and modeling cognition, PEM needs to be able to differentiate between conscious and unconscious mental states or processes. We will argue that one currently popular view, that the contents of conscious experience are determined by the ‘winning hypothesis’, falls short of fully accounting for conscious experience. It ignores the possibility that some states of a system can control that system’s behavior even though they are apparently not conscious. What follows from this is that the ‘winning hypothesis’ view does not provide a complete account of the difference between conscious and unconscious states in the probabilistic brain. We show how this problem for the received view can be resolved by augmenting PEM with Daniel Dennett’s multiple drafts model of consciousness. This move is warranted by the similar roles that attention and internal competition play in both the PEM framework and the multiple drafts model. (shrink)

Abstract In a recent issue of Neuroethics , I considered whether the notion of human dignity could help us in solving the moral problems the advent of the diagnostic category of minimally conscious state (MCS) has brought forth. I argued that there is no adequate account of what justifies bestowing all MCS patients with the special worth referred to as human dignity. Therefore, I concluded, unless that difficulty can be solved we should resort to other values than human dignity in (...) addressing the moral problems MCS poses. In his new book Christopher Kaczor criticizes the argument I put forward. Below, I respond to Kaczor’s criticism. I maintain that the considerations he presents do not undermine my argument nor succeed in providing adequate justification for the view that all MCS patients possess the worth referred to as human dignity. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s12152-011-9147-z Authors Jukka Varelius, Department of Behavioural Sciences and Philosophy, University of Turku, Turku, 20014 Finland Journal Neuroethics Online ISSN 1874-5504 Print ISSN 1874-5490. (shrink)

Dr. Vukov analyzing patients with disorders of consciousness, proposed that medical well-regarded policy recommendations cannot be justified by looking solely to patients’ actual levels of consciousness (minimally conscious state – MCS versus vegetative state – VS), but that they can be justified by looking to patients’ potential for consciousness. One objective way to estimate this potential (actual physical possibility) is to consider a neurophysiologically informed strategy. Ideally such strategy would utilize objective brain activity markers of consciousness/unconsciousness. (...) The Operational Architectonics (OA) theory of brain-mind functioning is an example of such a strategy. Besides being mathematically simple, neurophysiologically accurate, and compatible with the cognitive/phenomenal perspectives on consciousness, application of OA strategy to quantitative EEG analysis of patients in VS and MCS revealed that the absence of consciousness in VS is paralleled by impairment of overall EEG operational architecture. Specifically, neuronal assemblies become smaller, their life span shortened, and they became highly unstable and functionally disconnected (desynchronized). At the same time, fluctuating (minimal) awareness in patients in MCS was paralleled by partial restoration of EEG operational architecture (increased size, life span, and stability of neuronal assemblies, together with an increased number and strength of functional connections among them), approaching the level found in healthy fully conscious participants. Moreover OA strategy to EEG analysis allowed predicting the emergence of consciousness in VS patients after six years following the brain trauma. Therefore, the OA methodology could reliably predict which patients may regain consciousness, and thus determine which patients may have the potential for consciousness. (shrink)

In a recent issue of Neuroethics, I considered whether the notion of human dignity could help us in solving the moral problems the advent of the diagnostic category of minimally conscious state (MCS) has brought forth. I argued that there is no adequate account of what justifies bestowing all MCS patients with the special worth referred to as human dignity. Therefore, I concluded, unless that difficulty can be solved we should resort to other values than human dignity in addressing the (...) moral problems MCS poses. In his new book Christopher Kaczor criticizes the argument I put forward. Below, I respond to Kaczor’s criticism. I maintain that the considerations he presents do not undermine my argument nor succeed in providing adequate justification for the view that all MCS patients possess the worth referred to as human dignity. (shrink)

The notion of minimal, basic, pre-reflective or core self is currently debated in the philosophy of mind, cognitive sciences and developmental psychology. However, it is not clear which experiential features such a self is believed to possess. Studying the schizophrenic experience may help exploring the following aspects of the minimal self: the notion of perspective and first person perspective, the ‘mineness’ of the phenomenal field, the questions of transparency, embodiment of point of view, and the issues of (...) agency and ownership, considered as different and less fundamental than the feeling of mineness. Two clinical vignettes of patients with the diagnosis of schizophrenia will be presented: the first one, illustrating early illness stages, and the second case, of chronic schizophrenia, symptomatically marked by persistent hallucinations. Through their analysis, we will discuss the experiential dimensions of minimal self. (shrink)

This book extends the contemporary concept of the minimal self by introducing the affective core self. The overall aim is to integrate certain psychoanalytical ideas into the phenomenological investigation of passivity and reformulate the idea of the phenomenological unconscious. This volume contributes to the multidimensional analysis of the self by positioning the affective core self between the layers of the more minimal and the less minimal self. It underscores the importance of the unconscious in the (...) constitution of the affective core self by providing the comparative analysis of the phenomenological and the psychoanalytical unconscious. Furthermore, comparisons are drawn between Freud’s conception of the afterwardsness of trauma and the phenomenological notion of retroactive sense-constitution. The book concludes that retroactive sense-making is a double-sided phenomenon and differentiates between implicit-bodily and conscious-narrative retroactive sense-constitution. In order to bolster the idea of implicit-bodily sense-constitution the volume also examines and utilizes contemporary insights on the nature of body memory. The conclusion claims that the affective core self is constituted in time by means of the underlying processes of the two-sided retroactive sense-constitution. This text appeals to students and researchers working in phenomenology and philosophy of mind. (shrink)

In this paper, I present one possible way of arguing for the theory of minimal self-consciousness, namely, by an argument by elimination. Central to the argument are the following two claims: a) If a theory of consciousness cannot explain first-person self-reference, then the theory is false, and b) An anonymity theory cannot explain first-person self-reference. Consequently, the anonymity theory is false.

Neurostimulation to restore cognitive and physical functions is an innovative and promising technique for treating patients with severe brain injury that has resulted in a minimally conscious state (MCS). The technique may involve electrical stimulation of the central thalamus, which has extensive projections to the cerebral cortex. Yet it is unclear whether an improvement in neurological functions would result in a net benefit for these patients. Quality-of-life measurements would be necessary to determine whether any benefit of neurostimulation outweighed any harm (...) in their response to different degrees of cognitive and physical disability. These measures could also indicate whether the technique could be ethically justified and whether surrogates could give proxy consent to its use on brain-injured patients. (shrink)

The “disability paradox” is the idea that for those who become severely disabled, their own quality of life assessment remains at or slightly below the QoL assessments of normal controls. This is a source of skepticism regarding third-person QoL judgments of the disabled. I argue here that this skepticism applies as well to those who are in the minimally conscious state. For rather simple means of sustaining an MCS patient’s life, the cost of being wrong that the patient would not (...) want further support is high. Pair this cost with the reason to be skeptical of third-person judgments, and my argument suggests not withholding food and water from MCS patients. (shrink)

I present considerations surrounding pre-reflective self-consciousness, arising in work I am conducting on a new physicalist, process-based account of [phenomenal] consciousness. The account is called the meta-causal account because it identifies consciousness with a certain type of arrangement of meta-causation. Meta-causation is causation where a cause or effect is itself an instance of causation. The proposed type of arrangement involves a sort of time-spanning, internal reflexivity of the overall meta-causation. I argue that, as a result of the (...) account, any conscious process has PRSC. Hence, PRSC does not need to be taken as a stipulation or argued for on purely phenomenological grounds or as a necessary support for reflective consciousness. I also show how it is natural to the account that PRSC is not an additional, peripheral, sort of consciousness, but is intrinsic to all consciousness, thereby fitting claims about self-intimation and co-constitution by various authors, and also being amenable to an adverbial account. As part of this, consciousness of an external object is just the form that current self-consciousness takes, the meta-causal constitution of it being inextricably modulated by the causal relationship with the object. The article also discusses how MCA helps explore issues of for-me-ness, transparency of perceptual consciousness, and possible immediacy and non-relationality of self-consciousness. (shrink)

This paper relates to a formal statement of the mechanisms that are thought minimally necessary to underpin consciousness. This is expressed in the form of axioms. We deem this to be useful if there is ever to be clarity in answering questions about whether this or the other organism is or is not conscious. As usual, axioms are ways of making formal statements of intuitive beliefs and looking, again formally, at the consequences of such beliefs. The use of this (...) style of exposition does not entail a claim to provide a mathematically rigorous formal deductive system. Conventional mathematical notation is used to achieve clarity, although this is elaborated with natural language in an attempt to reduce terseness. In our view, making the approach axiomatic is synonymous with building clear usable tests for consciousness and is therefore a central feature of the paper. The extended scope of this approach is to lay down some essential properties that should be considered when designing machines that could be said to be conscious. In the broader discussion about the nature of consciousness and its neurological mechanisms, it may seem to some that axiomatisation is premature and continues to beg many questions. However, the approach is meant to be open- ended so that others can build further axiomatic clarifications that address the very large number of questions which, in the search for a formal basis for consciousness, still remain to be answered. Of course, in discussions about consciousness many will also argue that the subject is not one that may ever be formally addressed by means of axioms. The view taken in this paper is 'let's try to do it and see how far it gets'. (shrink)

There is no agreement on whether any invertebrates are conscious and no agreement on a methodology that could settle the issue. How can the debate move forward? I distinguish three broad types of approach: theory-heavy, theory-neutral and theory-light. Theory-heavy and theory-neutral approaches face serious problems, motivating a middle path: the theory-light approach. At the core of the theory-light approach is a minimal commitment about the relation between phenomenal consciousness and cognition that is compatible with many specific theories (...) of consciousness: the hypothesis that phenomenally conscious perception of a stimulus facilitates, relative to unconscious perception, a cluster of cognitive abilities in relation to that stimulus. This “facilitation hypothesis” can productively guide inquiry into invertebrate consciousness. What is needed? At this stage, not more theory, and not more undirected data gathering. What is needed is a systematic search for consciousness-linked cognitive abilities, their relationships to each other, and their sensitivity to masking. (shrink)