Jakob Hohwy

Is it rational to believe that the mind is identical to the brain? Identity theorists say it is (or looks like it will be, once all the neuroscientific evidence is in), and they base this claim on a general epistemic route to belief in identity. I re-develop this general route and defend it against some objections. Then I discuss how rational belief in mind–brain identity, obtained via this route, can be threatened by an appropriately adjusted version of the anti-physicalist knowledge argument. Responses to this threat usually appeal either to different modes of presentation or to phenomenal concepts. But neither type of response is satisfactory. I provide a novel response, which appeals to an innocuous epistemic peculiarity of phenomenal states, namely their, as I shall call it, evidential insulation.

The notion that the brain is a prediction error minimizer entails, via the notion of Markov blankets and self-evidencing, a form of global scepticism — an inability to rule out evil demon scenarios. This type of scepticism is viewed by some as a sign of a fatally flawed conception of mind and cognition. Here I discuss whether this scepticism is ameliorated by acknowledging the role of action in the most ambitious approach to prediction error minimization, namely under the free energy principle. I argue that the scepticism remains but that the role of action in the free energy principle constrains the demon’s work. This yields new insights about the free energy principle, epistemology, and the place of mind in nature.

In this paper, we consider how certain longstanding philosophical questions about mental representation may be answered on the assumption that cognitive and perceptual systems implement hierarchical generative models, such as those discussed within the prediction error minimization framework. We build on existing treatments of representation via structural resemblance, such as those in Gładziejewski :559–582, 2016) and Gładziejewski and Miłkowski, to argue for a representationalist interpretation of the PEM framework. We further motivate the proposed approach to content by arguing that it is consistent with approaches implicit in theories of unsupervised learning in neural networks. In the course of this discussion, we argue that the structural representation proposal, properly understood, has more in common with functional-role than with causal/informational or teleosemantic theories. In the remainder of the paper, we describe the PEM framework for approximate Bayesian inference in some detail, and discuss how structural representations might arise within the proposed Bayesian hierarchies. After explicating the notion of variational inference, we define a subjectively accessible measure of misrepresentation for hierarchical Bayesian networks by appeal to the Kullbach–Leibler divergence between posterior generative and approximate recognition densities, and discuss a related measure of objective misrepresentation in terms of correspondence with the facts.

Crispin Wright has sought to establish the possibility of ‘significant metaphysics’ in the shape of a common metric with which to measure the realism or robustness of various discourses. One means by which to place discourses in the metric is via the ‘cognitive command constraint’. Importantly, this constraint must be a priori. Richard Rorty has argued against this, that, given content is a function of standards of representationality, the a priori requirement cannot be satisfied. I show that this attack is inconsistent: to run his own argument Rorty must take recourse to a idealized view of identification of discourses which conflicts with his own basic premise about the determination of content. Hence Rorty’s argument should not lead us to conclude that significant metaphysics is impossible

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.

Three challenges to a unified understanding of delusions emerge from Radden's On Delusion (2011). Here, I propose that in order to respond to these challenges, and to work towards a unifying framework for delusions, we should see delusions as arising in inference under uncertainty. This proposal is based on the observation that delusions in key respects are surprisingly like perceptual illusions, and it is developed further by focusing particularly on individual differences in uncertainty expectations

An exciting theory in neuroscience is that the brain is an organ for prediction error minimization. This theory is rapidly gaining influence and is set to dominate the science of mind and brain in the years to come. PEM has extreme explanatory ambition, and profound philosophical implications. Here, I assume the theory, briefly explain it, and then I argue that PEM implies that the brain is essentially self-evidencing. This means it is imperative to identify an evidentiary boundary between the brain and its environment. This boundary defines the mind-world relation, opens the door to skepticism, and makes the mind transpire as more inferentially secluded and neurocentrically skull-bound than many would nowadays think. Therefore, PEM somewhat deflates contemporary hypotheses that cognition is extended, embodied and enactive; however, it can nevertheless accommodate the kinds of cases that fuel these hypotheses.

Consciousness. We have come to expect science to be able to explain all sorts of phenomena in the world (global warming, hereditary diseases, life – you name it). Consciousness is an anomaly in the success story of science for there is a real question whether science, in particular neuroscience, can explain much about what consciousness is. A good question to ask is how and to what extent consciousness resists scientific explanation. That might tell us something about what is special about consciousness.

This chapter seeks to recover an approach to consciousness from a general theory of brain function, namely the prediction error minimization theory. The way this theory applies to mental and developmental disorder demonstrates its relevance to consciousness. The resulting view is discussed in relation to a contemporary theory of consciousness, namely the idea that conscious perception depends on Bayesian metacognition; this theory is also supported by considerations of psychopathology. This Bayesian theory is first disconnected from the higher-order thought theory, and then, via a prediction error conception of action, connected instead to the global neuronal workspace theory. Considerations of mental and developmental disorder therefore show that a very general theory of brain function is relevant to explaining the structure of conscious perception; furthermore, this theory can subsume and unify two contemporary approaches to consciousness, in a move that seeks to elucidate the fundamental mechanism for selection of representational content into consciousness

Creatures that have different physical realizations than human beings may or may not be conscious. Ned Block’s ‘harder problem of consciousness’ is that naturalistic phenomenal realists have no conception of a rational ground for belief that they have or have not discovered consciousness in such a creature. Drawing on the notion of inference to the best explanation, it appears the arguments to these conclusions beg the question and ignore that explanation may be a guide to discovery. Thus, best explanation can both validate an interpretation of the evidence and lead to the discovery of consciousness

The effect of the body transfer illusion on the perceived strength of self- and externally-generated “tickle” sensations was investigated. As expected, externally generated movement produced significantly higher ratings of tickliness than those associated with self-generated movements. Surprisingly, the body transfer illusion had no influence on the ratings of tickliness, suggesting that highly surprising, and therefore hard to predict, experiences of body image and first-person perspective do not abolish the attenuation of tickle sensations. In addition, evidence was found that a version of the rubber hand illusion exists within the body transfer illusion. We situate our findings within the larger debate over sensory attenuation: there is an attenuation of prediction errors that depends upon the context in which sensory input is predicted , and sensory attenuation is a necessary consequence of self-generated movement irrespective of context . The results support the notion of active inference

This chapter explores the idea that the need to establish common knowledge is one feature that makes social cognition stand apart in important ways from cognition in general. We develop this idea on the background of the claim that social cognition is nothing but a type of causal inference. We focus on autism as our test-case, and propose that a specific type of problem with common knowledge processing is implicated in challenges to social cognition in autism spectrum disorder (ASD). This problem has to do with the individual’s assessment of the reliability of messages that are passed between people as common knowledge emerges. The proposal is developed on the background of our own empirical studies and outlines different ways common knowledge might be comprised. We discuss what these issues may tell us about ASD, about the relation between social and non-social cognition, about social objects, and about the dynamics of social networks.

Investigation of neural and cognitive processes underlying individual variation in moral preferences is underway, with notable similarities emerging between moral- and risk-based decision-making. Here we specifically assessed moral distributive justice preferences and non-moral financial gambling preferences in the same individuals, and report an association between these seemingly disparate forms of decision-making. Moreover, we find this association between distributive justice and risky decision-making exists primarily when the latter is assessed with the Iowa Gambling Task. These findings are consistent with neuroimaging studies of brain function during moral and risky decision-making. This research also constitutes the first replication of a novel experimental measure of distributive justice decision-making, for which individual variation in performance was found. Further examination of decision-making processes across different contexts may lead to an improved understanding of the factors affecting moral behaviour

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.

Most consciousness researchers, almost no matter what their views of the metaphysics of consciousness, can agree that the first step in a science of consciousness is the search for the neural correlate of consciousness (the NCC). The reason for this agreement is that the notion of ‘correlation’ doesn’t by itself commit one to any particular metaphysical view about the relation between (neural) matter and consciousness. For example, some might treat the correlates as causally related, while others might view the correlation as evidence for identity between conscious states and brain states. The common ground therefore seems to be that the scientific search for the NCC is largely independent of the metaphysics of consciousness

Nancy Cartwright argues that so-called capacities, not universal laws of nature, best explain the often complex way events actually unfold. On this view, science would represent a world that is fundamentally "dappled", or disunified, and not, as orthodoxy would perhaps have it, a world unified by universal laws of nature. I argue, first, that the problem Cartwright raises for laws of nature seems to arise for capacities too, so why reject laws of nature? Second, that in so far as there is a problem, it concerns the role of counterfactuals in explanation; I then briefly propose a simple model of counterfactual explanation. Finally, I investigate how a sophisticated version of the regularity theory of laws of nature (that of Ramsey-Lewis) can be neutral between the empirical hypotheses that the world is unified, and that the world is disunified.

According to one theory, the brain is a sophisticated hypothesis tester: perception is Bayesian unconscious inference where the brain actively uses predictions to test, and then refine, models about what the causes of its sensory input might be. The brain’s task is simply continually to minimise prediction error. This theory, which is getting increasingly popular, holds great explanatory promise for a number of central areas of research at the intersection of philosophy and cognitive neuroscience. I show how the theory can help us understand striking phenomena at three cognitive levels: vision, sensory integration, and belief. First, I illustrate central aspects of the theory by showing how it provides a nice explanation of why binocular rivalry occurs. Then I suggest how the theory may explain the role of the unified sense of self in rubber hand and full body illusions driven by visuotactile conflict. Finally, I show how it provides an approach to delusion formation that is consistent with one-deficit accounts of monothematic delusions

Autism spectrum disorder is characterised by differences in unimodal and multimodal sensory and proprioceptive processing, with complex biases towards local over global processing. Many of these elements are implicated in versions of the rubber hand illusion, which were therefore studied in high-functioning individuals with ASD and a typically developing control group. Both groups experienced the illusion. A number of differences were found, related to proprioception and sensorimotor processes. The ASD group showed reduced sensitivity to visuotactile-proprioceptive discrepancy but more accurate proprioception. This group also differed on acceleration in subsequent reach trials. Results are discussed in terms of weak top-down integration and precision-accuracy trade-offs. The RHI appears to be a useful tool for investigating multisensory processing in ASD