In this paper, I propose that those who reject higher-order theories of consciousness should not rule out the possibility of having conscious experiences that they cannot introspect. I begin by offering four arguments that such non-introspectible conscious experiences are possible. Next, I offer two arguments for thinking that we actually have such experiences. According to the first argument, it is unlikely that evolution would have furnished us with a faculty of introspection that worked flawlessly. According to the second argument, there (...) are many plausible potential sources of non-introspectible experiences. Given that all of these sources are at least somewhat plausible, it is fairly probable that we have some kind or other. Finally, I consider whether we might be justified in believing that we can introspect all of our conscious experiences if in fact we can. I show that current approaches to justifying belief in epiphenomenal qualia do not carry over. The upshot of these arguments is that we should be less certain that we really know what it feels like to be us. There may be much more to our experiences than we are aware of. (shrink)

Cognitive science typically postulates unconscious mental phenomena, computational or otherwise, to explain cognitive capacities. The mental phenomena in question are supposed to be inaccessible in principle to consciousness. I try to show that this is a mistake, because all unconscious intentionality must be accessible in principle to consciousness; we have no notion of intrinsic intentionality except in terms of its accessibility to consciousness. I call this claim the The argument for it proceeds in six steps. The essential point is that (...) intrinsic intentionality has aspectual shape: Our mental representations represent the world under specific aspects, and these aspectual features are essential to a mental state's being the state that it is. (shrink)

Many experimental findings with split-brain subjects intuitively suggest that each such subject has two minds. The conceptual and empirical basis of this duality intuition has never been fully articulated. This article fills that gap, by offering a reconstruction of early neuropsychological literature on the split-brain phenomenon. According to that work, the hemispheres operate independently of each other insofar as they interact via the mediation of effection and transduction—via behavior and sensation, essentially. This is how your mind and my mind interact (...) with each other, however, giving rise to the intuition that a split-brain subject has two minds. (shrink)

The attempt to model the structure of consciousness in split-brain subjects is ongoing. This paper concerns the recently proposed ?switch model? of split-brain consciousness, according to which a split-brain subject possesses only a single stream of consciousness, unified at and across time, that shifts from one hemisphere to the other from moment to moment. The paper argues that while the central explanatory element of the switch model may account for some aspects of split-brain consciousness, the best general picture of split-brain (...) consciousness is still offered by some version of the ?conscious duality model.? (shrink)

Abstract The subjectivity of conscious experience is a central feature of our mental life that puzzles philosophers of mind. Conscious mental representations are presented to me as mine, others remain unconscious. How can we make sense of the difference between them? Some representationalists (e.g. Tye) attempt to explain it in terms of non-conceptual intentional content, i.e. content for which one need not possess the relevant concept required in order to describe it. Hanna claims that Kant purports to explain the subjectivity (...) of conscious experience in this way. This paper examines this claim in some detail in the context of a more general criticism of this kind of attempt to explain subjectivity and proposes a different reading of Kant that also leads to an alternative account of subjectivity independent from content. (shrink)

Some philosophers have argued that so long as two neural events, within a subject, are both of the same type and both carry the same content, then these events may jointly constitute a single mental token, regardless of the sort of causal relation to each other that they bear. These philosophers have used this claim—which I call the “singularity-through-redundancy” position—in order to argue that a split-brain subject normally has a single stream of consciousness, disjunctively realized across the two hemispheres. This (...) paper argues, against this position, that the kind of causal relations multiple neural events bear to each other constrains the mental tokens with which functionalists who are realists can identify them. (shrink)

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 accompany conscious 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. In this and the next two chapters I defend the thesis that, necessarily, for any subject (of conscious mental states) at any time, all of that subject's conscious mental states (at that time) are part of a single, maximal state of consciousness. I call this thesis the "Unity Thesis." I proceed by considering some preliminary questions that might be raised about the Unity Thesis. For instance, the thesis presupposes that it is coherent to talk about parts of mental states. I consider objections by Tye and Searle and argue that the notion of an experiential part is unproblematic. In the remaining pages of the chapter, I present the source of the biggest challenge to the Unity Thesis: the data gathered from split-brain subjects. 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. I then consider two unorthodox views that the Consensus View does not take off the table: the views that a "collective consciousness" and a "spread consciousness" are possible. A collective subject is one that can enjoy the experiences of an indeterminate number of "lesser" subjects of consciousness by sharing them together with those subjects. A spread subject is one that can enjoy the experiences of an indeterminate number of lesser subjects of consciousness, but it does so, not by sharing those experiences with the lesser subjects, but by absorbing the lesser subjects of experience into itself, thereby erasing the traditional boundaries between the entities we intuitively think of as subjects of experience. I argue that, although the Consensus View does not decide against them, these views stretch the bounds of coherence and should not, therefore, be accepted. Having presented an account of what maximal state of consciousness is, I define a stream of consciousness in terms of a maximal states of consciousness. In the rest of chapter two, I consider and argue against a number of different ways of interpreting the split-brain data that are either inconsistent with the Unity Thesis or attribute more than one subject of consciousness to split-brain subjects. Among the views I consider are Lockwood's partial-unity view and the views, by theorists such as Sperry, Koch, Puccetti, Marks, and Tye, that split-brain subjects have two non-overlapping streams of consciousness. 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. According to Bayne's Switch Model, the consciousness of split-brain subjects can be likened to that of a ball that is passed back and forth between the two hemispheres of the upper-brain. The hemispheres take turns supporting a single stream of consciousness. I consider the empirical data in some detail and argue that the data is not as compatible with the Switch Model as Bayne claims. 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. It can be asked what it is like for a subject of experience when a higher-order state misrepresents its target first-order state. If what it is like for the subject corresponds to the content of the higher-order state, then it appears as though higher-order representation is unnecessary for conscious experience, for it would appear as though it is possible for a state to be conscious without being represented by a higher-order state. If what it is like corresponds to the content of the lower-order state, then it would again seem as though representation at the higher-order level is unnecessary for conscious experience, for the higher-order state would not seem to be doing any work in generating the experience. I consider and argue against two recent defences of Rosenthal's higher-order theory from the Mismatch Objection. Then I turn to Rosenthal's account of conscious unity. Rosenthal's account posits two mental mechanisms. I refer to the ways of accounting for conscious unity via these two mechanisms as the "gathering strategy" and the "common-ascription strategy" respectively. Both of these strategies, I argue, appear to locate the basis for certain phenomenal facts in higher-order representational facts. This raises a prima facie question: does Rosenthal's account of conscious unity land him square within the sights of the Mismatch Objection? Although the gathering strategy may ultimately be understood in a way that does not make it subject to the Mismatch Objection, Rosenthal has certain commitments that bar this strategy from serving as a complete account of conscious unity. This is problematic for Rosenthal, I argue, because his common-ascription strategy faces some difficult questions. This strategy makes conscious unity due to an implicit expectation a subject of consciousness has that, whenever he or she engages in introspection, an explicit sense of conscious unity will be generated. I argue that it is very difficult to see how such an implicit sense could both avoid the Mismatch Objection and do the work it needs to do in order to account for conscious unity. 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. The notion of self-consciousness invoked by the Ubiquity Thesis is a minimal one. In spite of the fact that the Ubiquity Thesis invokes only a minimal or thin conception of self-consciousness, I believe the thesis to be false and argue against it. In this chapter I take up the views of Husserl. Husserl is often regarded as the progenitor of the phenomenological tradition, a tradition in which many philosophers affirm the Ubiquity Thesis. I examine and argue against an interpretation of Husserl's work, one defended by Zahavi, according to which Husserl could be seen to defend the Ubiquity Thesis. One claim that Husserl makes is that, in order for an object to become the intentional target of a conscious state, it must be given to consciousness beforehand. It is possible, during acts of deliberate introspection, for consciousness to take itself as its object. On Husserl's view, this requires consciousness to be given to itself beforehand. This self-givenness of consciousness, argues Zahavi, can be seen as a kind of minimal self-consciousness. Husserl has also offered an account of this self-givenness of consciousness and it appears in his discussion of inner time-consciousness. I attempt to argue, using some of Husserl's other views regarding psychological stances (or standpoints), that consciousness is not given to itself outside of the adoption of a certain psychological standpoint. I also offer an alternative way of accounting for inner time-consciousness, one that does not have, as a built-in feature, that consciousness always has itself as a secondary object. 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. In the first part of the chapter, I take issue with the way in which Kriegel lays out the conceptual terrain. In particular, Kriegel countenances a property he calls "intransitive state self-consciousness." I argue that this way of speaking is confused. I then turn to considering Kriegel's account. Kriegel identifies the species of self-consciousness that pervades all of conscious experience with a peripheral awareness of one's own mental states. I argue that such a peripheral inner awareness does not accompany all of our mental states and, thus, that Kriegel's views do not give us reason to accept the Ubiquity Thesis. (shrink)

At any given time, a subject has a multiplicity of conscious experiences. A subject might simultaneously have visual experiences of a red book and a green tree, auditory experiences of birds singing, bodily sensations of a faint hunger and a sharp pain in the shoulder, the emotional experience of a certain melancholy, while having a stream of conscious thoughts about the nature of reality. These experiences are distinct from each other: a subject could experience the red book without the singing (...) birds, and could experience the singing birds without the red book. But at the same time, the experiences seem to be tied together in a deep way. They seem to be unified, by being aspects of a single encompassing state of consciousness. (shrink)

When does a human being cease to exist? For millennia, the answer to this question had remained largely unchanged: death had been diagnosed when heartbeat and breathing were permanently absent. Only comparatively recently, in the 1950s, rapid developments in intensive-care medicine called into question this widely accepted criterion. What had previously been deemed a permanent cessation of vital functions suddenly became reversible. -/- A new criterion of death was needed. It was suggested that the destruction of the brain could indicate (...) the death of the organism in the presence of external life support. Soon the so-called brain death became the new worldwide standard. In recent years, however, doubts about this neurological criterion have been growing. Is brain death really our death? -/- This is the question that this thesis seeks to answer. To this end, we shall connect the medical debate about the definition of death to the philosophical debate about personal identity. While we will find that the destruction of its brain does in fact not correspond to an organism’s death, we shall also ask whether the assumption that we are essentially organisms is correct. May brain death be the ceasing to exist of a different entity? -/- Substituting clinical case reports and considerations about human physiology for the use of thought experiments, the thesis takes a novel and philosophically unconventional approach to the problem of what we essentially are. We shall analyse various pathological conditions and their respective effects on the bodily and mental characteristics of our existence. We will conclude that brain death is indeed our death – but for reasons entirely different from those cited in the original justification of this criterion. (shrink)

What are we? Despite much discussion in historical and contemporary philosophy, we have not yet settled on an answer. A satisfactory personal ontology, an account of our metaphysical nature, will be informed by issues in the metaphysics of material objects. In the dissertation, I target two prominent materialist ontologies: animalism, the view that we are numerically identical to human organisms, and constitutionalism, the view that we are constituted by, but not identical to, human organisms. Because of the problems that arise (...) from endorsing these ontologies, I instead advance immaterialism, the view that we are essentially immaterial. In Chapter 2, I discuss how animalists must respond to a widely-discussed metaphysical puzzle, the problem of the many. This puzzle prompts some to endorse revisionary ontologies of material objects, and I argue that the animalist cannot appeal to these revisionary ontologies to solve the puzzle as it arises for personal ontology. In addition, solutions that don’t involve a commitment to revisionary ontology will be unavailable to the animalist: I argue that if animalists make use of non-revisionary solutions to the problem, they must abandon the most successful argument for their view. Absent their most successful argument, animalists will need to motivate the view in some other way. Some new arguments for animalism have been proposed, and I argue that they fail to give us reason to endorse animalism over competing ontologies. Without a strong argument, we should not prefer animalism over the other, more attractive, views. In Chapter 3, I show how constitutionalists face a different problem: explaining how the person is not the very same thing as the human organism, despite sharing the very same parts and occupying the very same physical space. We think that the person and the organism are different things because they have different modal profiles – the human organism can survive permanent loss of psychological life, but the person, presumably, cannot. Constitutionalists must then explain what grounds the difference in modal profiles, but such an explanation is hard to come by. This is an instance of the grounding problem, which is notoriously intractable. While the grounding problem is a well-known challenge to constitutional accounts of objects, I demonstrate that this puzzle is even more threatening when applied to persons. Some “solutions” to the problem fail to solve it at all, and solutions that might get the right result for ordinary objects require accepting that there are a multitude of persons where we ordinarily take there to be only one. We should not accept a personal ontology that requires a commitment to that multitude. I argue that the threat of the grounding problem is so great that we must reject the constitutionalist personal ontology. We will see from these puzzles in personal ontology that materialist solutions are either unsuccessful or yield unacceptable consequences. This should prompt us toward considering, instead, immaterialism. According to immaterialism, persons are not material objects, and the immaterialist can then provide solutions to the puzzles that threatened materialist ontologies. In Chapter 4, I outline these immaterialist solutions and show that the puzzles cannot be reinstantiated successfully against the immaterialist. I then discuss different available varieties of immaterialism and argue in defense of my preferred version. Ultimately, I argue that we are simple, immaterial entities that come into existence at the proper functioning of the brain. Endorsing this view of personal ontology permits us to adequately respond to metaphysical puzzles and retain judgments about persons that should be most important to us. In particular, the immaterialist has the resources to avoid the problem of too many thinkers and retain the judgment that there is exactly one person in circumstances where we take there to be just one. The immaterialist also has the resources to plausibly analyze thought experiments, such as cerebrum-swap cases, that threaten materialist ontologies. All things considered, it remains to be seen which personal ontology has the most evidence in its favor. In the context of debates that arise from material object metaphysics, however, evidence weighs in favor of immaterialism. Materialist personal ontologies are saddled with unacceptable responses to metaphysical puzzles, and endorsing materialism about persons requires taking on a very high cost: Either there are far more of us than we ordinarily take there to be, or there are no persons – far fewer of us than we ordinarily take there to be. Some might argue that these are the only acceptable options, so cost be damned. But we cannot afford to be so cavalier about our personal ontology. Instead, I advance immaterialist solutions to puzzles in personal ontology and propose that, in the interest of saving ourselves and everyone we love, we should seriously consider accounts according to which we are immaterial entities. (shrink)