Suppose someone hears a loud noise and at the same time sees a yellow flash. It seems hard to deny that the person can experience loudness and yellowness together. However, since loudness is experienced by the auditory sense whereas yellowness is experienced by the visual sense it also seems hard to explain how.

Is attention both necessary and sufficient for consciousness? Call this central question of this treatise, “Q.” We commonly have the experience of consciously paying attention to something, but is it possible to be conscious of something you are not attending to, or to attend to something of which you are not conscious? Where might we find examples of these? This treatise is a quest to find an answer to Q in two parts. Part I reviews the foundations upon which the (...) discourse on Q is built. Different inputs to Q produce different answers. After consideration of the many ways “attention” and “consciousness” have been defined, I settle upon phenomenal consciousness and Executive Attention (defined as a suite of strategies for structuring cognition for further processing implemented by the executive of working memory) as the most interesting inputs to Q, and the ones on which Part II focuses. Attention without consciousness seems relatively easy to establish empirically, but consciousness without attention is much harder. The putative candidates all seem to have major problems, but I build a strong abductive case for the hitherto ignored case of foveal phenomenal overflow. We consciously see far more detail in our foveal fields than we can Executively Attend, although there is a serious obstacle to our ever confirming that empirically—identifying conscious content relies on Executive Attentional report. Triangulating the capacity limitations of attention, consciousness, and working memory strengthens this case for consciousness without attention, and suggests that cognition must work something like my “Witches’ Hat Model,” on which content can become conscious outside of Executive Attention or working memory. I conclude with some reflections on the implications of my arguments for the discourse on Q, and for other discourses such as the ontologies of attention and consciousness, theories of consciousness, some other cognitive concepts, and ethical considerations in humans, animals, and machines. A conclusive answer to Q continues to elude us. It may perhaps be an ultimately insoluble conundrum. But it is the very essence of humanity to seek an answer, and in so doing, to improve our understanding of our own nature: “The proper study of mankind is man.”1. (shrink)

The problem of phenomenal unity consists in providing a phenomenological characterization of the difference between phenomenally unified and disunified conscious experiences. Potential solutions to PPU are faced with an important challenge. I show that this challenge can be conceived as a phenomenological dual to what is known as Bradley’s regress. This perspective facilitates progress on PPU by finding duals to possible solutions to Bradley’s regress and makes it intelligible why many characterize phenomenal unity in terms of the existence of a (...) single global conscious state. I call this latter view the “single state conception”. SSC is superficially attractive, because it seems to provide a solution to the phenomenological dual to Bradley’s regress, but should still be rejected, because it does not solve PPU; instead, it creates more problems; these problems can be avoided by alternative conceptions of phenomenal unity. (shrink)

Many vertebrate animals approximate, to various degrees, the “split‐brain” condition that results from surgery done in humans to treat severe epilepsy, with very limited connection between the left and right sides of the upper parts of the brain. The split‐brain condition has been the topic of extensive philosophical discussion, because it appears, in some circumstances, to give rise to two minds within one body. Is the same true of these animals? This article attempts to make progress on two difficult topics—animal (...) experience, and the consequences of the human split‐brain condition—by considering both at once. (shrink)

In this paper I argue that split-brain syndrome is best understood within an extended mind framework and, therefore, that its very existence provides support for an externalist account of conscious perception. I begin by outlining the experimental aberration model of split-brain syndrome and explain both: why this model provides the best account of split-brain syndrome; and, why it is commonly rejected. Then, I summarise Susan Hurley’s argument that split-brain subjects could unify their conscious perceptual field by using external factors to (...) stand-in for the missing corpus callosum. I next provide an argument that split-brain subjects do unify their perceptual fields via external factors. Finally, I explain why my account provides one with an experimental aberration model which avoids the problems typically levelled at such views, and highlight some empirical predictions made by the account. The nature of split-brain syndrome has long been considered mysterious by proponents of internalist accounts of consciousness. However, in this paper I argue that externalist theories can provide a straightforward explanation of the condition. I therefore conclude that the ability of externalist accounts to explain split-brain syndrome gives us strong reason to prefer them over internalist rivals. (shrink)

The phenomenology of the unity of consciousness can be analyzed in terms of perceptual spatial and object unity. Subject unity—what we commonly understand by “the unity of consciousness”—has no attendant phenomenology. The further, non-phenomenological, effects of unity can be analyzed in terms of the functional notion of access unity. The unity of consciousness in general can therefore be analyzed in terms of access unity. As a consequence, we can avoid the theoretical introduction of problematic notions such as subsumptive or phenomenal (...) unity. (shrink)

There are two different varieties of question concerning the unity of consciousness: questions about unity at a time, and unity over time. A recent trend in the debate about unity has been to attempt to provide a ‘generalized’ account that purports to solve both problems in the same way. This attempt can be seen in the accounts of Barry Dainton and Michael Tye. In this paper, I argue that there are crucial differences between unity over time and unity at a (...) time that make it impossible to provide a generalized account of unity. The source of these crucial differences is the phenomenon of the ‘continuity of consciousness’. I argue that accounts of unity over time have to provide an account of this continuity, and that there is no phenomenon analogous to continuity in the case of unity at a time. Attention to the continuity of consciousness reveals crucial structural differences between the two varieties of unity. These structural differences make it impossible to provide a generalized account of unity. I show that the problems faced by Dainton’s and Tye’s accounts in the light of the structural differences make their accounts of unity appear far less appealing than they might initially have looked. I conclude by noting that, in the light of the important differences between the two varieties of unity, it is a mistake to attempt to model accounts of unity over time on accounts of unity at a time. (shrink)

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.