The structure of consciousness

In this dissertation, I examine the nature and structure of consciousness. Conscious experience is often said to be phenomenally unified, and subjects of consciousness are often self-conscious. I ask whether these features necessarily accompanyconscious experience. Is it necessarily the case, for instance, that all of a conscious subject's experiences at a time are phenomenally unified? And is it necessarily the case that subjects of consciousness are self-conscious whenever they are conscious? I argue that the answer to the former is affirmative and the latter negative.;In the first chapter, I set the stage by distinguishing phenomenal unity from other species of conscious unity. A pair of conscious states is phenomenally unified if they are experienced together as part of a single experience that encompasses them both.;The Unity Thesis is formulated using the notion of a maximal state of consciousness. In the second chapter, I attempt to precisify this notion in a way that does not pre-emptively decide the debate over the Unity Thesis. In informal terms, a maximal state of consciousness is a sum of conscious states that are i) simultaneous, ii) have the same subject, and iii) all have a conjoint phenomenology. I call this the Consensus View.;In chapter three, I consider a recent attempt by Bayne to account for the split-brain data in a way that does not attribute two streams of consciousness to them. I close the chapter by presenting the rough outline of an interpretation of the split-brain data that is consistent with both the Unity Thesis and the split-brain data.;In chapter four, I turn from defending the Unity Thesis to examining an attempt to account for conscious unity. Rosenthal has offered a theory of conscious unity as an extension of his higher-order theory of consciousness. I consider his account of conscious unity in light of a well-known objection to his theory: the (Representational) Mismatch Objection.;In chapter five, the discussion turns from the unity of consciousness to self-consciousness. The question that is considered in this and the last chapter is the question whether conscious experience is necessarily accompanied by self-consciousness. The affirmative answer to this question I call the Ubiquity Thesis. I spend some time distinguishing robust conceptions of self-consciousness from minimal conceptions of self-consciousness.;In the sixth and final chapter, I take up a contemporary defence of the Ubiquity Thesis. Kriegel, a higher-order theorist like Rosenthal, has argued that every conscious state is conscious in virtue of the fact that it represents itself. This self-representation is understood as a kind of self-consciousness and, thus, his theory can be seen as affirming the Ubiquity Thesis. (Abstract shortened by UMI.).