Online research in philosophy

Consciousness has been defined as that annoying period between naps, and this grumpy definition may not be wholly facetious, if Michael Tye's latest book is right. Tye's main goal here is to develop a theory of the phenomenal unity of experience at a time, and its diachronic analog, the moment-to-moment continuity of one's experiential stream from the time one wakes up to the time consciousness lapses.

According to conventional wisdom, the split-brain syndrome puts paid to the thesis that consciousness is necessarily unified. The aim of this paper is to challenge that view. I argue both that disunity models of the split-brain are highly problematic, and that there is much to recommend a model of the split-brain—the switch model—according to which split-brain patients retain a fully unified consciousness at all times. Although the task of examining the unity of consciousness through the lens of the split-brain syndrome is not a new one—such projects date back to Nagel’s seminal paper on the topic—the time is ripe for a re-evaluation of the issues.

Some argue that split-brain cases undermine the thesis that phenomenal consciousness is necessarily unified. This paper defends the phenomenal unity thesis against Michael Tye's (2003 ) version of that argument. Two problems are identified. First, his argument relies on a questionable analysis of the split-brain data. Second, his analysis leads to the view that in experimental situations split-brain patients are not single subjects – a result that would render the analysis harmless to the phenomenal unity thesis.

This paper concerns the relationships between persons, brains, behaviour, and psychological explanation. Tye defines a ‘psychological framework’ (PF) as a set of token beliefs, desires, intentions, memories, streams of consciousness, higher-order mental states, etc., that ‘form a coherent whole’ and against which a creature’s ‘behavior can be explained’ (p. 141). A person is the subject of such a psychological framework. Each person has one PF, and with each new PF there is a new person. Meanwhile materialism tells us, according to Tye, that brains are the bearers of mental states. In other words, ‘each person is a brain’ (p. 142) — or rather a ‘global physical state of the brain,’ since Tye believes that a single brain might realize multiple PFs and thus constitute multiple persons. Most of this paper simply assumes Tye’s account of personal identity, in order to expose certain contradictions within what Tye says about personhood in split-brain subjects. Towards the end of the paper, however, I turn to alternative accounts of persons. While a method of individuating persons grounded in scientific psychology would identify persons with psychological frameworks, as Tye does, perhaps an account of personhood grounded either in a non-psychological science, or in non-scientific psychology, would better fit the interests we have in personal identity.

theorists insist that consciousness is essentially unified. Other theorists assert that the unity of consciousness is an illusion, and that consciousness is often, if not invariably, disunified. Unfortunately, it is rare for proponents of either side of the debate to explain what the unity of consciousness might involve. What would it mean for consciousness to be unified? In this chapter I provide a brief cartography of the unity of consciousness. In the next section I introduce a number of unity relations that can hold between conscious states, and in the following sections I show how these unity relations can be used to construct various conceptions of the unity of consciousness—what I call unity theses. These unity theses provide us with a set of reference points by means of which we can orient discussions of the (dis)unity of consciousness.

Foundations. The phenomenal field ; Phenomenal unity : mereology ; Phenomenal unity : closure -- Consciousness unified?. Motivating the unity thesis ; How to evaluate the unity thesis ; Fragments of consciousness? ; Anosognosia, schizophrenia, and multiplicity ; Hypnosis ; The split-brain syndrome -- Implications. The quilt of consciousness ; The body ; The self.

The crux of this book is expressed in one short sentence from the Preface: 'Unity is a fundamental part of our experience, something that is crucial to its phenomenology' [p.xii], and the crux of this sentence is that the unity of consciousness is not a matter of phenomenal relations existing between distinct experiences – the received view [p.17], but the existence of relations between the contents of experiences – the one experience view [p.25ff]. In its simplest form Tye's claim is that: all our conscious states, whether visual, auditory, olfactory, tactual or gustatory, whether imagistic or emotional are experienced concurrently; they 'are phenomenologically unified ... [and] ... Phenomenological unity is a relation between qualities represented in experience, not between qualities of experiences. [p.36].

In Consciousness and persons, Michael Tye (Tye, M. (2003). Consciousness and persons. Cambridge, MA: MIT Press.) develops and defends a novel approach to the unity of consciousness. Rather than thinking of the unity of consciousness as involving phenomenal relations between distinct experiences, as standard accounts do, Tye argues that we should regard the unity of consciousness as involving relations between the contents of consciousness. Having developed an account of what it is for consciousness to be unified, Tye goes on to apply his account of the unity of consciousness to the split-brain syndrome. I provide a critical evaluation of Tye's account of the unity of consciousness and the split-brain syndrome.