Jakob Hohwy

There is surprising evidence that introspection of our phenomenal states varies greatly between individuals and within the same individual over time. This puts pressure on the notion that introspection gives reliable access to our own phenomenology: introspective unreliability would explain the variability, while assuming that the underlying phenomenology is stable. I appeal to a body of neurocomputational, Bayesian theory and neuroimaging findings to provide an alternative explanation of the evidence: though some limited testing conditions can cause introspection to be unreliable, mostly it is our phenomenology itself that is variable. With this account of phenomenal variability, the occurrence of the surprising evidence can be explained while generally retaining introspective reliability

Some monothematic types of delusions may arise because subjects have unusual experiences. The role of this experiential component in the pathogenesis of delusion is still not understood. Focussing on delusions of alien control, we outline a model for reality testing competence on unusual experiences. We propose that nascent delusions arise when there are local failures of reality testing performance, and that monothematic delusions arise as normal responses to these. In the course of this we address questions concerning the tenacity with which delusions are maintained, their often bizarre content, the patients' inability to dismiss them, and their often circumscribed character

Cognitive neuroscience aspires to explain how the brain produces conscious states. Many people think this aspiration is threatened by the subjective nature of introspective reports, as well as by certain philosophical arguments. We propose that good neuroscientific explanations of conscious states can consolidate an interpretation of introspective reports, in spite of their subjective nature. This is because the relative quality of explanations can be evaluated on independent, methodological grounds. To illustrate, we review studies that suggest that aspects of the feeling of being in control of one's bodily movement can be explained in terms of the complex and surprising way the brain predicts movement. This is a modest type of functional, contrastive explanation. Though we do not refute the threatening philosophical arguments, we show that they do not apply to this type of explanation.

A central part of Kripke's influential interpretation of Wittgenstein's sceptical argument about meaning is the rejection of dispositional analyses of what it is for a word to mean what it does. In this paper I show that Kripke's arguments prove too much: if they were right, they would preclude not only the idea that dispositional properties can make statements about the meanings of words true, but also the idea that dispositional properties can make true statements about paradigmatic dispositional properties such as a cup's fragility or a person's bravery. However, since dispositional properties can make such statements true, Kripke-Wittgenstein's arguments against dispositionalism about meaning are mistaken.

The theory of rationality has traditionally been concerned with the investigation of the norms of rational thought and behaviour, and with the reasoning pro‐cedures that satisfy them. As a consequence, the investigation of irrationality has largely been restricted to the behaviour or thought that violates these norms. There are, how‐ever, other forms of irrationality. Here we propose that the delusions that occur in schizophrenia constitute a paradigm of irrationality. We examine a leading theory of schizophrenic delusion and propose that some delusions can be traced to a violation of a condition on thought we call egocentricity. We argue that the violation of egocen‐tricity leads to irrational states that cannot be explained by the traditional categories of irrationality and conclude, therefore, that these states belong in a new branch of the theory of irrationality, that of experiential irrationality.

The normative character of meaning creates deep problems for the attempt to give a reductive explanation of the constitution of meaning. I identify and critically examine an increasingly popular Carnap-style position, which I call Internalized Meaning Factualism (versions of which I argue are defended by, e.g., Robert Brandom, Paul Horwich and Huw Price), that promises to solve the problems. According to this position, the problem of meaning can be solved by prohibiting an external perspective on meaning constituting properties. The idea is that if we stick to a perspective on meaning that is internal to meaning discourse, then we can preserve the normativity of meaning and yet locate meaning in the natural world. I develop a generic motivation for this position, but argue that, since this motivation is consistent with the Ramsey–Carnap–Lewis–Jackson reductionist strategy, internalized meaning factualism is unstable. The problems about the normativity of meaning can therefore not be sidestepped in this way.

We use the hierarchical nature of Bayesian perceptual inference to explain a fundamental aspect of the temporality of experience, namely the phenomenology of temporal flow. The explanation says that the sense of temporal flow in conscious perception stems from probabilistic inference that the present cannot be trusted. The account begins by describing hierarchical inference under the notion of prediction error minimization, and exemplifies distrust of the present within bistable visual perception and action initiation. Distrust of the present is then discussed in relation to previous research on temporal phenomenology. Finally, we discuss how there may be individual differences in the experience of temporal flow, in particular along the autism spectrum. The resulting view is that the sense of temporal flow in conscious perception results from an internal, inferential process.

The search for the neural correlates of consciousness is in need of a systematic, principled foundation that can endow putative neural correlates with greater predictive and explanatory value. Here, we propose the predictive processing framework for brain function as a promising candidate for providing this systematic foundation. The proposal is motivated by that framework’s ability to address three general challenges to identifying the neural correlates of consciousness, and to satisfy two constraints common to many theories of consciousness. Implementing the search for neural correlates of consciousness through the lens of predictive processing delivers strong potential for predictive and explanatory value through detailed, systematic mappings between neural substrates and phenomenological structure. We conclude that the predictive processing framework, precisely because it at the outset is not itself a theory of consciousness, has significant potential for advancing the neuroscience of consciousness.

In rubber hand illusions and full body illusions, touch sensations are projected to non-body objects such as rubber hands, dolls or virtual bodies. The robustness, limits and further perceptual consequences of such illusions are not yet fully explored or understood. A number of experiments are reported that test the limits of a variant of the rubber hand illusion. Methodology/Principal Findings A variant of the rubber hand illusion is explored, in which the real and foreign hands are aligned in personal space. The presence of the illusion is ascertained with participants' scores and temperature changes of the real arm. This generates a basic illusion of touch projected to a foreign arm. Participants are presented with further, unusual visuotactile stimuli subsequent to onset of the basic illusion. Such further visuotactile stimulation is found to generate very unusual experiences of supernatural touch and touch on a non-hand object. The finding of touch on a non-hand object conflicts with prior findings, and to resolve this conflict a further hypothesis is successfully tested: that without prior onset of the basic illusion this unusual experience does not occur. Conclusions/Significance A rubber hand illusion is found that can arise when the real and the foreign arm are aligned in personal space. This illusion persists through periods of no tactile stimulation and is strong enough to allow very unusual experiences of touch felt on a cardboard box and experiences of touch produced at a distance, as if by supernatural causation. These findings suggest that one's visual body image is explained away during experience of the illusion and they may be of further importance to understanding the role of experience in delusion formation. The findings of touch on non-hand objects may help reconcile conflicting results in this area of research. In addition, new evidence is provided that relates to the recently discovered psychologically induced temperature changes that occur during the illusion.

Cognitive neuropsychiatry attempts to understand psychiatric disorders as disturbances to the normal function of human cognitive organisation, and it attempts to link this functional framework to relevant brain structures and their pathology. This recent scientific discipline is the natural extension of cognitive neuroscience into the domain of psychiatry. We present two examples of recent research in cognitive neuropsychiatry: delusions of control in schizophrenia, and affective disorders. The examples demonstrate how the cognitive approach is a fruitful and necessary supplement to the otherwise successful biological psychiatry paradigm, which tend to bypass the cognitive level. Philosophy concerns some of the core concepts involved in psychiatric illness, particularly concerning rationality, thought and action, reality testing, and the self. We present concrete examples that illustrate how philosophical conceptual tools can be particularly important for the construction and interpretation of the cognitive models relevant to the understanding of psychiatric illness. We conclude that cognitive neuropsychiatry is a fruitful and necessary supplement to biological psychiatry. Furthermore, cognitive neuropsychiatry itself may benefit significantly from employing philosophical conceptual tools in the interpretation and construction of its cognitive models. The cognitive and philosophical approaches may thus be further steps towards a scientific psychopathology.

The free energy principle says that any self-organising system that is at nonequilibrium steady-state with its environment must minimize its free energy. It is proposed as a grand unifying principle for cognitive science and biology. The principle can appear cryptic, esoteric, too ambitious, and unfalsifiable—suggesting it would be best to suspend any belief in the principle, and instead focus on individual, more concrete and falsifiable ‘process theories’ for particular biological processes and phenomena like perception, decision and action. Here, I explain the free energy principle, and I argue that it is best understood as offering a conceptual and mathematical analysis of the concept of existence of self-organising systems. This analysis offers a new type of solution to long-standing problems in neurobiology, cognitive science, machine learning and philosophy concerning the possibility of normatively constrained, self-supervised learning and inference. The principle can therefore uniquely serve as a regulatory principle for process theories, to ensure that process theories conforming to it enable self-supervision. This is, at least for those who believe self-supervision is a foundational explanatory task, good reason to believe the free energy principle.

At present, the science of consciousness is structured around the search for the neural correlates of consciousness. One of the alleged advantages of the NCCs framework is its metaphysical neutrality—the fact that it begs no contested questions with respect to debates about the fundamental nature of consciousness. Here, we argue that even if the NCC framework is metaphysically neutral, it is structurally committed, for it presupposes a certain model—what we call the Lite-Brite model—of consciousness. This, we argue, represents a serious liability for the NCC framework for the plausibility of the Lite-Brite model is very much an open question, and the science of consciousness would be better served by a framework that does not presuppose it. Drawing on interventionist ideas in the philosophy of science, we suggest that the Difference-Maker framework can provide just such an alternative. Instead of searching for the neural correlates of consciousness, we ought to be searching for the difference makers of consciousness. We detail how a shift to searching DMCs will change both the practice of consciousness science and the interpretation of existing results.

What is the function of cognition? On one influential account, cognition evolved to co-ordinate behaviour with environmental change or complexity. Liberal interpretations of this view ascribe cognition to an extraordinarily broad set of biological systems—even bacteria, which modulate their activity in response to salient external cues, would seem to qualify as cognitive agents. However, equating cognition with adaptive flexibility per se glosses over important distinctions in the way biological organisms deal with environmental complexity. Drawing on contemporary advances in theoretical biology and computational neuroscience, we cash these distinctions out in terms of different kinds of generative models, and the representational and uncertainty-resolving capacities they afford. This analysis leads us to propose a formal criterion for delineating cognition from other, more pervasive forms of adaptive plasticity. On this view, biological cognition is rooted in a particular kind of functional organisation; namely, that which enables the agent to detach from the present and engage in counterfactual inference.

The last decade has seen impressive and intriguing advances in the exploration of vestiges of consciousness in patients with disorders of consciousness . Consciousness is an extremely complex area of research so it is difficult to provide unequivocal interpretations of these new findings from DOC-studies. This review therefore provides a conceptual analysis of a series of key studies in this area of research. The main upshot is that different studies of preserved consciousness in DOC are best seen as targeting different aspects of consciousness rather than a unitary property of being conscious. These different aspects of consciousness thus seem to dissociate and fractionate in DOC. This provides a deeper understanding of the nature and structure of consciousness in general, and it provides suggestions for future research in DOC and the science of consciousness. Further methodological, conceptual, and ethical issues are discussed