A post by Cecily Whiteley.
It is standardly thought that imaginative experiences are not only ontologically homogeneous, but also phenomenally so. When asked to imagine the Notre-Dame Cathedral, construct visually elaborate daydreams or picture the face of a loved one, we naturally assume that in such cases - episodes of sensory imagining - each of us undergoes experiences of roughly the same sort: conscious experiences involving mental imagery. Recent empirical findings however, suggest that this ordinary assumption is mistaken. In a number of recent studies Adam Zeman and colleagues at the University of Exeter document the main neurobehavioural features of a new mental imagery generation disorder known as aphantasia - a condition characterised by the total (or otherwise severely reduced) incapacity to produce visual forms of mental imagery. There are, it turns out, a small percentage of the population - current estimations fall around the 2% benchmark - who lack a mind’s eye.
Cases of so-called ‘extreme imagination’ such as aphantasia (along with ‘hyperphantasia’ - the possession of extremely vivid, and often disruptive mental imagery) constitute a rich and, as of yet, underused resource for theorists of imagination. The lifelong loss (or overabundance) of mental imagery exhibited in these cases provide the ultimate test case for philosophical theories of imagination - forcing us to revise standard accounts of the aesthetic, cognitive and epistemic role of sensory imagination, and to reconsider our understanding of its place in our mental lives (see, for example, the recent post on this blog which examines the curious phenomenon of aphantasic artists). In my view, the theoretical significance of extreme imagination is not limited to the assessment of these questions. Here, I’ll suggest that aphantasia raises important theoretical considerations in the context of a different, and somewhat surprising, debate in the philosophy of consciousness: that over the nature and ontological status of dreams.
According to one leading theory in the philosophy and science of consciousness, dreams are best analysed in terms of imaginative experiences. Dreams, on this view are not to be identified, as the predominant Cartesian view claimed, with the kinds of perceptual experiences one undergoes when one is hallucinating, but are rather constituted - to the extent that dreams have visual content - by sensory imagination; the sort of visual mental imagery that subjects with aphantasia, by hypothesis, lack. In this post, I’ll outline the case for thinking that the aforementioned studies of aphantasia give us reason to reject the imagination model of dreaming, standardly understood (and thus, that this theory is currently empirically inadequate), before sketching what I take to be the strongest response on behalf of the proponent of the imagination model to this empirical challenge. To preemptively summarise: I think that the dream reports of aphantasic subjects provide strong reason to reject the standard imagination theory of dreaming, unless we abandon one of its central tenets. The rejection of this thesis will lead us toward the modified (and perhaps the more independently plausible) claim that dreams constitutively involve non-voluntary or inactive forms of imagination.
The imagination model of dreaming then states that dreams are, in a fundamental sense, imaginative. But what does this theory commit us to more specifically? According to Jonathan Ichikawa, who provides the most extensive treatment of the view in recent literature, we can take the imagination model of dreaming as combining three claims:
(i) Imagery: dreams essentially involve mental imagery - experiences of the kind which occur when we imagine what something looks, feels, smells or tastes like.
(ii) Imaginings: the belief-like states that we take towards the content of our dreams are instances of propositional imagination.
(iii) Subject to the will: Imagination is essentially and fundamentally an agentive phenomenon - the distinction between imagination and perceptual-hallucinatory experiences is to be made on the basis that the former is necessarily ‘‘subject to the will’’ (if not always under our voluntary control).
While Ichikawa offers us various arguments in support of these theses (the second of which has obvious implications for the viability of skeptical dream arguments), of particular relevance here is his claim that the imagination model of dreaming is motivated not only by conceptual-philosophical considerations, but also supported by various forms of neuropsychological evidence which suggest that dreaming and imagination share a common neural basis. Here Ichikawa cites the work of neuroscientist Mark Solms, whose leading clinico-anatomical study of dreams describes a disorder in which patients report the isolated cessation or reduction of visual imagery in dreams. Documenting the main neurobehavioural characteristics of this dream disorder, Solms reports that patients with this disorder describe analogous deficiencies in their waking visual imagery. Ichikawa writes that this ought to push us toward the endorsement of an imagination model of dreaming:
‘‘Considering patients with brain damage resulting in imaginative deficits is particularly illuminating: such subjects tend to exhibit precisely analogous deficits in dreaming’’ (2016;254).
In light of this, the relevance of Zeman et al.’s studies on aphantasia to this debate should, hopefully, be obvious. As I see it, aphantasic subjects - characterised as lacking the capacity to generate visual mental imagery in any agential capacity from birth - provide a novel empirical test case for an imagination model of dreaming defended along these lines. As currently stated, the imagination model of dreaming appears to be committed to the prediction that aphantasic subjects would report dreams with little or no visual content. The problem, and basis of the empirical challenge then, is that the majority of aphantasics report the experience of rich visual dreams:
Despite their substantial (9/21) or complete (12/21) deficit in voluntary visual imagery, as judged by the VVIQ, the majority of participants described involuntary imagery. This could occur during wakefulness, usually in the form of ‘flashes’ (10/21) and/or during dreams (17/21) confirming a significant dissociation between voluntary and involuntary imagery (p < .01, McNemar Test). (2015)
Rather than confirming the predictions made by the imagination model of dreaming then, the dream reports documented in these studies go directly against it, providing evidence of multiple cases in which subjects report a sustained, lifelong loss of waking imagery whilst the capacity for rich visual dreaming is retained. This challenge relies on the following four (broad) claims:
(1) Subjects with aphantasia lack the agential capacity to generate and consciously experience sensory mental imagery.
(2) Visual imagery in dreams is to be understood, and accounted for solely in terms of, imagery of this kind.
(3) Dream reports accurately reflect dream experience such that aphantasic dreams are correctly described as having visual content.
(4) An adequate ontology of dreams must have the resources to account for empirical considerations similar to those raised by the dream reports of aphantasics.
There is a lot to be said about these claims, the full discussion of which goes well beyond this post (although I’m happy to discuss these considerations further in the comments). For now, I’ll note the following: (1) follows from what the studies show, along with a plausible claim about the nature of introspection (see also this recent article); (2) as noted, follows from Ichikawa’s imagination model of dreaming. This leaves the proponent of the imagination model of dreaming with the rejection of (3) or (4). In addition to the fact that both enjoy broad, if not unanimous, acceptance in the surrounding literature (for a nice discussion and defense of dream reports in ideal conditions see here), the more pertinent problem for Ichikawa when faced with the prospect of rejecting these claims is that both are relied upon in the existing psychological and - in the case of (3) - conceptual arguments relating to reflection on dreams and their phenomenal character Ichikawa utilises in order to motivate the position to begin with. As such, if a proponent of this model of dreaming opts to reject claim (3) or (4), this would come at a considerable cost, removing or substantially weakening the case for the position that they started with.
Are we forced to abandon an imagination model of dreaming as a result? While this may ultimately turn out to be the correct solution, to do so now would, I think, be premature. The problem in my view lies in Ichikawa’s commitment to - and his combination of an imagination view of dreaming with - an agentialist theory of imagination in claim (2). Fortunately, recent literature suggests that an imagination model of dreaming needn’t necessarily be committed to this claim. Motivated by the need to provide a philosophical analysis of the state of wakeful consciousness - as that which necessitates a kind of practical self-knowledge ( of ‘what we are up to’) resulting from the exercise of autonomous mental agency - an alternative suggestion receiving growing attention has it that dreams and other non-wakeful states ought to be analysed in terms of the absence of this distinctive feature of wakefulness (O'Shaughnessy 2002, Soteriou 2017, Crowther 2018). That is to say, the constitutive difference between wakeful and non-wakeful conditions is given in terms of the (in)capacity to exercise agency over our mental lives - to perform mental actions - which enables the distinctive sort of self-knowledge characteristic of wakeful consciousness. Matthew Soteriou (2017) sums up the proposal as follows:
‘‘In short, [in the dream state] one suffers from a sort of mental paralysis - a form of mental paralysis that doesn’t even allow for the possibility of failed attempts to exercise agency over one’s thinking. But it is a form of mental paralysis that is accompanied by the illusion of agency - the illusion of seeming to affirm, seeming to judge seeming to decide, seeming to be mentally active’’ (13).
When combined with (i) and (ii) a general claim regarding the nature of dreaming follows which - insofar as aphantasic subjects are not lacking the wakeful manifestation of this form of imagery avoids the challenge sketched above:
(2*) dreaming essentially involves instances of passive or non-agential forms of imagination.
Can this theory accommodate the phenomenon of lucid dreaming, and is there an independently plausible alternative theory of imagination with which this theory can be supplemented? I think there are good answers available to such questions, but I’ll leave discussion of these, and dream reports of subjects with overactive hyperaphantasia (can you guess the content of their dream reports?) for another time.
Crowther, T. (2018). Experience, dreaming, and the phenomenology of wakeful consciousness . In F.Dorsch, F.MacPherson, & M.Nida-Rumelin(Eds.) Phenomenal presence. Oxford:Oxford University Press.
Ichikawa, Jonathan (2009). Dreaming and imagination. Mind and Language 24 (1):103-121.
Ichikawa, Jonathan. (2016). Imagination, dreaming, and hallucination. In Amy Kind (Ed.), Routledge Handbook of the Philosophy of Imagination (pp. 149–162). London: Routledge.
Keogh, R & Pearson, J (2018). The blind mind: No sensory visual imagery in aphantasia. Cortex.
O'Shaughnessy, Brian (2002). Dreaming. Inquiry : An Interdisciplinary Journal of Philosophy 45 (4):399-432.
Solms, Mark (1997) The Neuropsychology of Dreams: A Clinico-Anatomical Study, Hillsdale, NJ: Erlbaum.
Soteriou, Matthew (2017). Dreams, agency, and judgement. Synthese:1-16.
Zeman et al. (2010) Loss of imagery phenomenology with intact visuo-spatial task performance: A case of ‘blind imagination’. Neuropsychologia. Volume 48, 1 (145-155).
Zeman et al. (2015) Lives Without Imagery - Congenital Aphantasia. Cortex (378-30)
Zeman et al. (2016) Reflections on aphantasia. Cortex, Volume 74 (336-337)
Zeman et al. (2018). The Eye's mind - Visual imagination, neuroscience and the humanities. Cortex 105.(1-3).