My research concerns the nature of consciousness, its phenomenal character, and its computational, psychological, and biological bases. I build bridges between personal and sub-personal levels of explanation by means of reflection on perceptual phenomenology and the results of cognitive science. My dissertation embodies this aim through chapters on the unity of consciousness, the nature of subjectivity, and the relation between memory and perceptual experience.
Dissertation Summary – Essays on the Architecture of Experience
We don’t know how to individuate experiences: When does one experience end and another begin? We don’t know how to classify experiences into their fundamental kinds: Are perception and hallucination fundamentally the same or different experiential kinds? We don't know under what conditions experiences stream together or break apart, nor what makes it the case that one or two subjects undergo them, or have them, or simply are them. In short, some very basic questions about the nature of consciousness remain wide open.
My approach begins with the observation that there are many kinds of minds, brains, bodies and experiences. For instance, certain humans are born with naturally (i.e. non-surgically) split-brains. The dissertation’s first chapter examines this unusual and overlooked population, and finds that some such individuals fail to perform even the most basic comparisons between visual fields. For example, they cannot say whether a red patch in the right visual field is the same or different as a green patch in the left. When tested within a single visual field, however, the same individuals perform well above chance. And more puzzling still, I find that some conscious integration between visual fields is preserved. Guided by these results, the chapter develops a more fine-grained account of the unity of consciousness than previously conceived. It locates conscious disunity at the level of experiential contents, rather than such coarse-grained psychological capacities as agency and perception. This analysis opens the door for future empirical and theoretical research, and exemplifies a content-forward approach to the structure of experience.
The dissertation’s second chapter considers the nature of our experience of the world behind the head. Attending to such experience presents an opportunity to examine the conditions under which experience counts as perceptual, cognitive, mnemonic, or imaginative, and so forth. By analyzing the phenomenology and mechanistic bases of rear space experience, I argue that such experience is constitutively perceptual and mnemonic. This claim and the evidence I adduce for it make contact with recent debates over the relation between perception, memory, and imagination, and reveal a distinctively non-sensory aspect to the phenomenal character of experience.
The final chapter of the dissertation addresses the relation between subjects and experience. It charts a middle ground between ‘thin’ views on which subjects are identified with bare bundles of experiences, and ‘thick’ views on which subjects are identified with the physical substrate(s) of those experiences. On the view I propose, such subjects are individuated by robust causal-functional patterns among experiential contents, rather than by primitive co-consciousness or bare qualitative character. Subjects of experience are, in my view, kinds of intentional objects. I defend the surprising consequence that very minimal forms of experience do not entail subjects that have them.
Of the dissertation’s three chapters, one is being prepared for publication at Ergo (‘A New Argument for Partial Unity’), one is under review (‘The World Behind the Head’), and the third is being prepared for review (‘The Unity of Consciousness and the Self’).
Future Research
My future research will expand on the dissertation by developing two papers which are in early stages. The first asks what grounds the apparent spatial unity of perceptual experience. The second asks what the possible and actual solutions are to the coordination problem that arises when multiple or partial streams of consciousness co-occur in one body.
On the topic of spatial unity, evidence suggests that objects are perceptually represented in many different frames of reference. For example, they are perceptually located both relative to the eyes (“straight ahead”) and the surroundings (“inside the box”). This generates a puzzle about why spatial experience is not more disjointed than it is – for instance, why we rarely seem to experience a single object as in two fundamentally distinct places at once, and never seem to experience objects in terms of their bare allocentric coordinates. I want to explain why this is so. The view I’m interested in developing is that perceptual space is initially disunified, and becomes more unified over time as one learns to coordinate one’s body parts, perceptual modalities, and intuitive physics models. This view predicts that spatial disunity can be induced by decoupling certain representational systems, as perhaps occurs in Balint’s syndrome.
On the topic of coordinating multiple or partial streams of consciousness, it is remarkable how easily split-brain animals navigate their environments. For instance, birds and many other animals are born with naturally split-brains. A duckling that imprints on an object with one eye will be indifferent to that object with the other eye for several hours. Moreover, many birds have laterally placed eyes, and thus receive largely distinct streams of visual information. They nonetheless manage to land on narrow perches, catch flying insects, and perform countless other sophisticated actions. I want to explore a solution to this puzzle built on the observation that split-brain animals act habitually so as to minimize interhemispheric conflict. For instance, birds perform head saccades, quickly swiveling their heads back and forth to present the stimulus to both eyes. Such actions occur reflexively and unconsciously, and yet appear to ground a kind of consubjectivity or implicit co-consciousness.
Articles
"A New Argument for Partial Unity " forthcoming at Ergo.
Humans whose corpus callosum has been surgically severed – “split-brain” humans – have received the lion’s share of attention in unity of consciousness research. Two dominant views have emerged: one-stream views according to which split-brain consciousness is wholly unified, and two-streams views according to which split-brain consciousness is wholly disunified. A third option involving violations of the transitivity of co-consciousness, the partially unified stream view, has seemed to theorists conceptually problematic and empirically unsettled. This paper offers a new argument for the partially unified stream view based on a different population of humans whose corpus callosum never developed in the first place – congenitally acallosal humans. It proposes a “fine-grained” account of the structure of acallosal consciousness on which highly determinate contents, but not broad psychological capacities, are disunified.
"The World Behind The Head " (under review)
In what sense are we aware of objects behind the head? Do we experience such objects perceptually, or are they merely remembered, imagined, kinesthetically sensed, or cognitively believed? How is the space behind us represented more generally, and which mental capacities underwrite our experience of the world behind the head? This paper argues that standard models of such experience are insufficient. It develops and defends a novel account according to which the world behind the head is represented by two semi-independent memory systems: a spatial updating system primarily attuned to transportable objects like keys, cups, phones, and other agents, and a cognitive mapping system primarily attuned to non-transportable objects like buildings, walls, and furniture. Each system has a distinct mechanistic and neural basis, and makes a distinct phenomenal contribution to experience. I show how this account intersects with recent philosophical debates about the relationship between perception, imagination, and memory, and supports a view on which rear space experience is a form of present-tensed, memory-constituted perceptual experience.
"The Unity of Consciousness and the Self" (manuscript)
This paper addresses the relation between the unity of consciousness and the self qua subject of experience. It charts a middle ground between ‘thin’ views on which subjects are identified with bare bundles of experiences, and ‘thick’ views on which subjects are identified with the physical substrate(s) of those experiences. On the view I propose, such subjects are individuated by robust causal-functional patterns among experiential contents, rather than by primitive co-consciousness or bare qualitative character. Subjects of experience are, in my view, kinds of intentional objects. Bayne (2010) endorses a similar view he labels Virtual Phenomenalism. I defend such views against objections, including that they render the self unreal and/or typically disunified. Lastly, I defend the surprising consequence that very minimal forms of experience do not entail subjects that have them.
"Co-Embodiment and the Puzzle of Fluent Action" (manuscript)
Given that multiple or partial streams of consciousness sometimes co-occur in one body, it is remarkable how easily such animals navigate their environments. For instance, birds and many other animals are born with naturally split-brains. A duckling that imprints on an object with one eye will be indifferent to that object with the other eye for several hours. Moreover, many birds have laterally placed eyes, and thus receive largely distinct streams of visual information. They nonetheless manage to land on narrow perches, catch flying insects, and perform countless other sophisticated actions. This paper explores a solution to this puzzle built on the observation that split-brain animals act habitually so as to minimize interhemispheric conflict. For instance, birds perform head saccades, quickly swiveling their heads back and forth to present the stimulus to both eyes. Such actions occur reflexively and unconsciously, and yet appear to ground a kind of consubjectivity or implicit co-consciousness.