Tim Bayne

Rapid progress in artificial intelligence (AI) capabilities has drawn fresh attention to the prospect of consciousness in AI. There is an urgent need for rigorous methods to assess AI systems for consciousness, but significant uncertainty about relevant issues in consciousness science. We present a method for assessing AI systems for consciousness that involves exploring what follows from existing or future neuroscientific theories of consciousness. Indicators derived from such theories can be used to inform credences about whether particular AI systems are conscious. This method allows us to make meaningful progress because some influential theories of consciousness, notably including computational functionalist theories, have implications for AI that can be investigated empirically.

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.

This collection of essays focuses on the interface between delusions and self-deception. As pathologies of belief, delusions and self-deception raise many of the same challenges for those seeking to understand them. Are delusions and self-deception entirely distinct phenomena, or might some forms of self-deception also qualify as delusional? To what extent might models of self-deception and delusion share common factors? In what ways do affect and motivation enter into normal belief-formation, and how might they be implicated in self-deception and delusion? The essays in this volume tackle these questions from both empirical and conceptual perspectives. Some contributors focus on the general question of how to locate self-deception and delusion within our taxonomy of psychological states. Some contributors ask whether particular delusions - such as the Capgras delusion or anosognosia for hemiplegia - might be explained by appeal to motivational and affective factors. And some contributors provide general models of motivated reasoning, against which theories of pathological belief-formation might be measured.

Consciousness is—or is alleged to be—related to free will in a number of ways. This chapter distinguishes two main points of contact. The first is related to belief in the existence of free will. Here, it is argued that one might appeal to the experience of freely willing an action to explain why belief in the reality of free will is widespread and/or to explain why that belief is true (or at least reasonable). The second point of contact between consciousness and free action/will holds that consciousness is in some way necessary for free action/will. The chapter considers this proposal in light of a number of distinctions: between consciousness as a property of agents and consciousness as a property of mental state, and between consciousness understood as wakefulness and consciousness understood as experience.

This chapter considers three approaches to the question “What kind of behavioral experiments, if any, could determine whether anyone has free will?” The first approach might be adopted by those who hold that some agents (e.g., young children and non-human animals) lack free will, whereas others (e.g., neurotypical humans) possess it. Given this perspective, behavioral experiments that distinguish infants and non-human animals from neurotypical human agents could be relevant to adjudicating whether a target individual has free will. A second approach is skeptical that anyone has free will. The worries that animate most free-will skeptics cannot be resolved by appeal to behavioral experiments. A third approach concerns the concept of free will. Here, there is a rich literature in experimental philosophy that employs behavioral methods to clarify the ordinary concept of free will.

The cognitive phenomenology debate concerns the nature of conscious thought. On one side of the debate are those who deny that thought has a _sui generis_ phenomenal character. This view—which I refer to as ‘conservatism’—holds that to the extent that thoughts are phenomenally conscious, their phenomenal character is purely sensory. On the other side of the debate are those who hold that thought _is_ characterized by _sui generis_ non-sensory phenomenal states—‘cognitive phenomenology’. My concern in this chapter is not with the question of whether cognitive phenomenology exists, but with the very debate about itself: why do philosophers of mind disagree about the nature of conscious thought? I argue for a semantic analysis of this debate: conservatives and liberals lack a shared conception of what cognitive phenomenology would be. I go on to argue that the real lesson of the cognitive phenomenology debate is that there may be no unitary concept of phenomenal consciousness.

This chapter investigates whether consciousness is multisensory—in particular, whether consciousness contains experiences associated with distinct modalities at the same time. It describes those who endorse a positive answer to this question as endorsing a multisensory view of the structure of consciousness, while those who endorse a negative answer as having a unisensory view. Based on the evidence reviewed in this chapter, the conclusion is that, as yet, the evidence that one might expect to have been published were the multisensory view of consciousness to be the correct one is largely absent, at least when considering the senses of audition, vision, and touch. As such, the authors tentatively endorse the unisensory view of consciousness.

Recent years have seen a blossoming of theories about the biological and physical basis of consciousness. Good theories guide empirical research, allowing us to interpret data, develop new experimental techniques and expand our capacity to manipulate the phenomenon of interest. Indeed, it is only when couched in terms of a theory that empirical discoveries can ultimately deliver a satisfying understanding of a phenomenon. However, in the case of consciousness, it is unclear how current theories relate to each other, or whether they can be empirically distinguished. To clarify this complicated landscape, we review four prominent theoretical approaches to consciousness: higher-order theories, global workspace theories, re-entry and predictive processing theories and integrated information theory. We describe the key characteristics of each approach by identifying which aspects of consciousness they propose to explain, what their neurobiological commitments are and what empirical data are adduced in their support. We consider how some prominent empirical debates might distinguish among these theories, and we outline three ways in which theories need to be developed to deliver a mature regimen of theory-testing in the neuroscience of consciousness. There are good reasons to think that the iterative development, testing and comparison of theories of consciousness will lead to a deeper understanding of this most profound of mysteries.

This chapter addresses another Kantian topic: the unity of consciousness. It looks at certain arguments that have been made against the unity of consciousness to determine whether they are good arguments against the unity thesis as we understand it. After fleshing out the unity thesis further, it applies the thesis to certain currently popular philosophical theories of consciousness, arguing that the thesis is incompatible with these theories: if the unity thesis is true, then these theories are false. The goal is not to conclusively prove the unity thesis, and indeed it is not certain that it is true. But it is suggested at least that the thesis is plausible, that it captures a strong intuition about the nature of consciousness, and that there are no knockdown arguments against it. If the thesis is true, it is likely to have important consequences for a theory of consciousness.

We seem to enjoy a very special kind of epistemic relation to our own conscious states. In The Conscious Mind (TCM), David Chalmers argues that our phenomenal judgments are fully‐justified or certain because we are acquainted with the phenomenal states that are the objects of such judgments. Chalmers holds that the acquaintance account of phenomenal justification is superior to reliabilist accounts of how it is that our PJs are justified, because it alone can underwrite the certainty of our phenomenal judgments. I argue that Chalmers is unable to sustain this claim.

The phenomenal character of perceptual experience involves the representation of colour, shape and motion. Does it also involve the representation of high‐level categories? Is the recognition of a tomato as a tomato contained within perceptual phenomenality? Proponents of a conservative view of the reach of phenomenal content say ‘No’, whereas those who take a liberal view of perceptual phenomenality say ‘Yes’. I clarify the debate between conservatives and liberals, and argue in favour of the liberal view that high‐level content can directly inform the phenomenal character of perception.

Beat perception has received very little attention from either philosophers of mind or philosophers of music. This neglect is unfortunate, for the topic is rich with philosophical interest. This article addresses two questions. The first concerns the nature of our experience of musical beat. Here, we argue that experiences of beat are forms of auditory perception. The second question concerns the nature of musical beat itself: what are beats? We defend a form of anthropocentric realism about beats: beats are mind‐independent properties of sound sequences whose nature can be understood only in relation to our perceptual capacities.

This paper addresses the question of whether large language model-powered chatbots are capable of assertion. According to what we call the Thesis of Chatbot Assertion (TCA), chatbots are the kinds of things that can assert, and at least some of the output produced by current-generation chatbots qualifies as assertion. We provide some motivation for TCA, arguing that it ought to be taken seriously and not simply dismissed. We also review recent objections to TCA, arguing that these objections are weighty. We thus confront the following dilemma: how can we do justice to both the considerations for and against TCA? We consider two influential responses to this dilemma - the first appeals to the notion of proxy-assertion; the second appeals to fictionalism - and argue that neither is satisfactory. Instead, reflecting on the ontogenesis of assertion, we argue that we need to make space for a category of proto-assertion. We then apply the category of proto-assertion to chatbots, arguing that treating chatbots as proto-assertors provides a satisfactory resolution to the dilemma of chatbot assertion.

A foundational issue for the science and philosophy of consciousness concerns the function(s) of consciousness – what consciousness does for any particular aspect of psychological or neural processing. In spite of progress in consciousness science, false assumptions and a lack of clarity regarding how best to approach the functions of consciousness represent an ongoing and serious roadblock to progress. Misguided approaches to the function(s) of consciousness have the potential to mangle explanatory priorities, and divert attention, effort, and funding away from useful questions and experimental paradigms. In this paper we offer a way forward: the capacity-based approach to the function(s) of consciousness. This approach flows out of a general explanatory approach that is influential in the philosophy of science and psychology (but not consciousness studies), according to which the mind is understood in terms of a structured collection of capacities. And capacities are explained by empirically discovered facts that identify functions (causal roles) played by empirically identified parts of a system. After elucidating this capacity-based approach to the mind, we show how consciousness fits within it. We then argue that this approach avoids problems that plague theory-based approaches to identifying the function(s) of consciousness, avoids mistakes endemic to the common strategy of looking for the function(s) of consciousness by asking what consciousness is necessary for, and re-orients explanatory priorities in a way that better focuses consciousness science, and that suggests fruitful avenues for experimentation.

Given its ubiquitous presence in everyday experience, it is surprising that the phenomenology of doing—the experience of being an agent—has received such scant attention in the consciousness literature. But things are starting to change, and a small but growing literature on the content and causes of the phenomenology of first-person agency is beginning to emerge.2 One of the most influential and stimulating figures in this literature is Daniel Wegner. In a series of papers and his book The Illusion of Conscious Will (ICW) Wegner has developed..

Hypnosis appears to generate unusual---and sometimes even astonishing---changes in the contents of consciousness. Hypnotic subjects report perceiving things that are not there, they report not perceiving things that are there, and they report unusual alterations in the phenomenology of agency. In addition to apparent alterations in the contents of consciousness, hypnosis also appears to involve alterations in the structure of consciousness. According to many theorists---most notably Hilgard---hypnosis demonstrates that the unity of consciousness is an illusion (Hilgard 1977)

Which systems/organisms are conscious? New tests for consciousness (‘C-tests’) are urgently needed. There is persisting uncertainty about when consciousness arises in human development, when it is lost due to neurological disorders and brain injury, and how it is distributed in nonhuman species. This need is amplified by recent and rapid developments in artificial intelligence (AI), neural organoids, and xenobot technology. Although a number of C-tests have been proposed in recent years, most are of limited use, and currently we have no C-tests for many of the populations for which they are most critical. Here, we identify challenges facing any attempt to develop C-tests, propose a multidimensional classification of such tests, and identify strategies that might be used to validate them.

Neural organoids are laboratory-generated entities that replicate certain structural and functional features of the human brain. Most neural organoids are disembodied—completely decoupled from sensory input and motor output. As such, questions about their potential capacity for consciousness are exceptionally difficult to answer. While not disputing the need for caution regarding certain neural organoid types, this paper appeals to two broad constraints on any adequate theory of consciousness—the first involving the dependence of consciousness on embodiment; the second involving the dependence of consciousness on representations—to argue that disembodied neural organoids are not plausible candidates for consciousness.

In the early modern period one can find unity of consciousness arguments in the writings of Rene Descartes and G. W. Leibniz, and in the recent literature they have been defended by David Barnett, William Hasker, and Richard Swinburne (among others). Descartes's unity of consciousness argument for dualism is to be found in the sixth of his Meditations on First Philosophy. Descartes claims that his unity of consciousness argument was itself sufficient to establish substance dualism. Swinburne's central line of argument involves deploying a number of puzzle cases. He argues that our intuitions about these cases can be accommodated only by adopting a “further fact” view of the self, according to which the continued existence of a person over time consists in the continued existence of a mental substance, and “it is metaphysically possible that the substance acquires a totally new body, totally new apparent memories, and character”.

In "The Disunity of Consciousness," Gerard O'Brien and Jon Opie argue that human consciousness is not synchronically unified. They suggest that the orthodox conception of the unity of consciousness admits of two readings, neither of which they find persuasive. According to them, "a conscious individual does not have a single consciousness, but several distinct phenomenal consciousnesses, at least one for each of the senses, running in parallel." They call this conception of consciousness the _multi-track account. I make three points in reply: (1) O'Brien and Opie's characterization of the orthodox conception of the unity of consciousness is problematic; (2) their arguments in support of the multitrack account are unpersuasive; and (3) the phenomenon of intersensory integration suggests that O'Brien and Opie are wrong to claim that "the only sense in which it is correct to talk of a 'unified' consciousness (...) is that in which the representational contents of the various components coincide."

Viewed from a certain perspective, nothing can seem more secure than introspection. Consider an ordinary conscious episode—say, your current visual experience of the colour of this page. You can judge, when reflecting on this experience, that you have a visual experience as of something white with black marks before you. Does it seem reasonable to doubt this introspective judgement? Surely not—such doubt would seem utterly fanciful. The trustworthiness of introspection is not only assumed by commonsense, it is also taken for granted by many of theorists about the mind. Within both philosophy and the science of consciousness it is widely held that introspection is generally reliable, at least with respect to the question of one’s current (or immediately prior) conscious states. Without this assumption, we could not make sense of theorists’ widespread use of introspection, both in support of their own position and to undermine that of their opponents.

In 1997, a Scottish surgeon by the name of Robert Smith was approached by a man with an unusual request: he wanted his apparently healthy lower left leg amputated. Although details about the case are sketchy, the would-be amputee appears to have desired the amputation on the grounds that his left foot wasn’t part of him – it felt alien. After consultation with psychiatrists, Smith performed the amputation. Two and a half years later, the patient reported that his life had been transformed for the better by the operation [1]. A second patient was also reported as having been satisfied with his amputation [2]