Cecily Whiteley

Aphantasia is a recently discovered disorder characterised by the total incapacity to generate visual forms of mental imagery. This paper proposes that aphantasia raises important theoretical concerns for the ongoing debate in the philosophy and sci- ence of consciousness over the nature of dreams. Recent studies of aphantasia and its neurobehavioral correlates reveal that the ma- jority of aphantasics, whilst unable to produce visual imagery while awake, nevertheless retain the capacity to experience rich visual dreams. This finding constitutes a novel explanandum for theories of dreaming. Specifically, I argue that the recent dream reports of aphantasics constitute an empirical challenge to the emerging family of views which claim that dreams are essentially imaginative ex- periences, constitutively involving the kinds of mental imagery which aphantasics, ex-hypothesi, lack. After presenting this challenge in the context of Jonathan Ichikawa’s recent arguments for this view, I argue that this empirical challenge may be overcome if the ima- gination theorist abandons Ichikawa’s account of dreaming in favour of a modified version. This involves the claim that dreams are essentially inactive and constitutively involve non voluntary forms of imagination. I conclude with a suggestion for further research which can test the viability of this alternative hypothesis, and move the debate forward.

Understanding the biological basis of consciousness is one of the central challenges for modern science. Is a mature scientific explanation really possible, and if so, how should consciousness science be organized so as to achieve this? This thesis is a collection of four papers which approach these questions via an account of the natural categories or ‘kinds’, drawn from philosophy of science, to which paradigmatic mental phenomena like consciousness belong. The central claims defended in the thesis are twofold. Firstly, that to facilitate a mature science of consciousness it is crucial to explicitly introduce a new organizing concept of consciousness modelled on the kinds of concepts which underpin previous successful explanations of other natural phenomena – that of a natural kind concept of consciousness. This draws on the general observation that some concepts are better suited to scientific theorizing about the world than others, and thus that progress in scientific and philosophical domains can be (and indeed, has often been) made by working to refine our existing conceptual schemes to reflect this. Secondly, that a mature science of consciousness will be one which recognizes the reality and explanatory importance of a particular category of mental phenomena called ‘global states of consciousness’ which includes dreaming and wakefulness. Examination of this latter claim leads to a third idea explored and motivated in the thesis which brings consciousness science into closer connection with psychiatry. This is the hypothesis that Major Depressive Disorder involves a change to a subject’s global state of consciousness, marking a change from a state of ordinary wakeful consciousness to an altered ‘depressive state’ of consciousness akin to a dream or psychedelic state.

First-person reports of major depressive disorder reveal that when an individual becomes depressed a profound change or ‘shift’ to one’s conscious experience occurs. The depressed person reports that something fundamental to their experience has been disturbed or shifted, a change associated with the common but elusive claim that when depressed one finds oneself in a ‘different world’ detached from reality and other people. Existing attempts to utilize these phenomenological observations in a psychiatric context are challenged by the fact that this experiential ‘shift’ characteristic of depression appears mysterious and resists analysis in scientific terms. This article offers a way out of this predicament. The hypothesis proposed is that when an individual becomes depressed, the individual departs from a state of ordinary wakeful consciousness and enters a distinctive global state of consciousness akin to dreaming and the psychedelic state. After unpacking and motivating this hypothesis in the context of research in consciousness science, I outline two of its important implications for the neurobiology of depression and psychedelic psychiatry. The upshot is a promising and conceptually well-motivated hypothesis about depression that is apt for empirical uptake and development.

First-person reports of Major Depressive Disorder reveal that when an individual becomes depressed a profound change or ‘shift’ to one’s conscious experience occurs. The depressed person reports that something fundamental to their experience has been disturbed or shifted; a change associated with the common but elusive claim that when depressed one finds oneself in a ‘different world’ detached from reality and other people. Existing attempts to utilise these phenomenological observations in a psychiatric context are challenged by the fact that this experiential ‘shift’ characteristic of depression appears mysterious and resists analysis in scientific terms. This paper offers a way out of this predicament. The hypothesis proposed is that when an individual becomes depressed, the individual departs from a state of ordinary wakeful consciousness and enters a distinctive global state of consciousness akin to dreaming and the psychedelic state. After unpacking and motivating this hypothesis in the context of research in consciousness science, I outline two of its important implications for the neurobiology of depression and psychedelic psychiatry. The upshot is a promising and conceptually well-motivated hypothesis about depression which is apt for empirical uptake and development.

Aphantasia is a recently discovered disorder characterised by the total incapacity to generate visual forms of mental imagery. This paper proposes that aphantasia raises important theoretical concerns for the ongoing debate in the philosophy and science of consciousness over the nature of dreams. Recent studies of aphantasia and its neurobehavioral correlates reveal that the majority of aphantasics, whilst unable to produce visual imagery while awake, nevertheless retain the capacity to experience rich visual dreams. This finding constitutes a novel explanandum for theories of dreaming. Specifically, I argue that the recent dream reports of aphantasics constitute an empirical challenge to the emerging family of views which claim that dreams are essentially imaginative experiences, constitutively involving the kinds of mental imagery which aphantasics, ex-hypothesi, lack. After presenting this challenge in the context of Jonathan Ichikawa’s recent arguments for this view, I argue that this empirical challenge may be overcome if the imagination theorist abandons Ichikawa’s account of dreaming in favour of a modified version. This involves the claim that dreams are essentially inactive and constitutively involve non voluntary forms of imagination. I conclude with a suggestion for further research which can test the viability of this alternative hypothesis, and move the debate forward.