Thomas Metzinger

The goal of this article is to present a first list of ethical concerns that may arise from research and personal use of virtual reality (VR) and related technology, and to offer concrete recommendations for minimizing those risks. Many of the recommendations call for focused research initiatives. In the first part of the article, we discuss the relevant evidence from psychology that motivates our concerns. In Section “Plasticity in the Human Mind,” we cover some of the main results suggesting that one’s environment can influence one’s psychological states, as well as recent work on inducing illusions of embodiment. Then, in Section “Illusions of Embodiment and Their Lasting Effect,” we go on to discuss recent evidence indicating that immersion in VR can have psychological effects that last after leaving the virtual environment. In the second part of the article, we turn to the risks and recommendations. We begin, in Section “The Research Ethics of VR,” with the research ethics of VR, covering six main topics: the limits of experimental environments, informed consent, clinical risks, dual-use, online research, and a general point about the limitations of a code of conduct for research. Then, in Section “Risks for Individuals and Society,” we turn to the risks of VR for the general public, covering four main topics: long-term immersion, neglect of the social and physical environment, risky content, and privacy. We offer concrete recommendations for each of these 10 topics, summarized in Table 1.

The goal of this short chapter, aimed at philosophers, is to provide an overview and brief explanation of some central concepts involved in predictive processing (PP). Even those who consider themselves experts on the topic may find it helpful to see how the central terms are used in this collection. To keep things simple, we will first informally define a set of features important to predictive processing, supplemented by some short explanations and an alphabetic glossary. The features described here are not shared in all PP accounts. Some may not be necessary for an individual model; others may be contested. Indeed, not even all authors of this collection will accept all of them. To make this transparent, we have encouraged contributors to indicate briefly which of the features are necessary to support the arguments they provide, and which (if any) are incompatible with their account. For the sake of clarity, we provide the complete list here, very roughly ordered by how central we take them to be for “Vanilla PP” (i.e., a formulation of predictive processing that will probably be accepted by most researchers working on this topic). More detailed explanations will be given below. Note that these features do not specify individually necessary and jointly sufficient conditions for the application of the concept of “predictive processing”. All we currently have is a semantic cluster, with perhaps some overlapping sets of jointly sufficient criteria. The framework is still developing, and it is difficult, maybe impossible, to provide theory-neutral explanations of all PP ideas without already introducing strong background assumptions.

In mental action there is no motor output to be controlled and no sensory input vector that could be manipulated by bodily movement. It is therefore unclear whether this specific target phenomenon can be accommodated under the predictive processing framework at all, or if the concept of “active inference” can be adapted to this highly relevant explanatory domain. This contribution puts the phenomenon of mental action into explicit focus by introducing a set of novel conceptual instruments and developing a first positive model, concentrating on epistemic mental actions and epistemic self-control. Action initiation is a functionally adequate form of self-deception; mental actions are a specific form of predictive control of effective connectivity, accompanied and possibly even functionally mediated by a conscious “epistemic agent model”. The overall process is aimed at increasing the epistemic value of pre-existing states in the conscious self-model, without causally looping through sensory sheets or using the non-neural body as an instrument for active inference.

This metatheoretical paper investigates mind wandering from the perspective of philosophy of mind. It has two central claims. The first is that, on a conceptual level, mind wandering can be fruitfully described as a specific form of mental autonomy loss. The second is that, given empirical constraints, most of what we call “conscious thought” is better analyzed as a subpersonal process that more often than not lacks crucial properties traditionally taken to be the hallmark of personal-level cognition - such as mental agency, explicit, consciously experienced goal-directedness, or availability for veto control. I claim that for roughly two thirds of our conscious life-time we do not possess mental autonomy (M-autonomy) in this sense. Empirical data from research on mind wandering and nocturnal dreaming clearly show that phenomenally represented cognitive processing is mostly an automatic, non-agentive process and that personal-level cognition is an exception rather than the rule. This raises an interesting new version of the mind-body problem: How is subpersonal cognition causally related to personal-level thought? More fine-grained phenomenological descriptions for what we called “conscious thought” in the past are needed, as well as a functional decomposition of umbrella terms like “mind wandering” into different target phenomena and a better understanding of the frequent dynamic transitions between spontaneous, task-unrelated thought and meta-awareness. In an attempt to lay some very first conceptual foundations for the now burgeoning field of research on mind wandering, the third section proposes two new criteria for individuating single episodes of mind-wandering, namely, the “self-representational blink” (SRB) and a sudden shift in the phenomenological “unit of identification” (UI). I close by specifying a list of potentially innovative research goals that could serve to establish a stronger connection between mind wandering research and philosophy of mind.

I have learned a lot from Josh Weisberg’s substantial criticism in his well-crafted and systematic commentary. Unfortunately, I have to concede many of the points he intelligently makes. But I am also flattered by the way he ultimately uses his criticism to emphasize some of those aspects of the theory that can perhaps possibly count as exactly the core of my own genuine contribution to the problem—and nicely turns them back against myself. And I am certainly grateful for a whole range of helpful clarifications.

As Flanagan remarks at the outset, many philosophers and researchers in the cognitive and neurosciences today believe that a naturalistic solution to the mind-body problem will eventually be found. Optimistic attitudes of this sort are usually inspired by the remarkable theoretical success so far achieved under the information-processing approach. The information-processing approach rests on a number of ubiquitous background assumptions. The most central of these is that treating human beings and their brains as information-processing systems may open precisely those levels of description under which the classical philosophical questions can be reformulated and finally answered. Many philosophers today try to treat traditional puzzles in this field - like the mind-brain-relationship, intentionality or self-awareness - by analyzing them in a top-down-fashion, i.e. by reformulating them in an information-processing terminology. In doing so one of their goals, usually, is eventually to naturalize those theoretical problems, to transform them into problems tractable by empirical science.

In this speculative paper I would like to show how important the integration of mental content is for a theory of phenomenal consciousness. I will draw the reader's attention to two manifestations of this problem which already play a role in the empirical sciences concerned with consciousness: The binding problem and the superposition problem. In doing so I hope to be able to leave the welltrodden paths of the debate over consciousness. My main concern is to gain a fresh access to the familiar theoretical difficulties associated with the concept of 'consciousness'.

Cognitive enhancement aims at optimizing a specific class of information-processing functions: cognitive functions, physically realized by the human brain. This article deals with ethical issues in cognitive enhancement. It discusses some standard conceptual issues related to the notion of “cognitive enhancement” and then continues from a purely descriptive point of view by briefly reviewing some empirical aspects and sketching the current situation. Several enhancement strategies are being tested and used. Then the chapter offers some reflections on the treatment or enhancement distinction. It turns to normative issues by describing standard topics in current debates, then highlighting three examples of relevant novel questions under an ethical perspective. It is of central importance to be able to draw on long-term studies yielding data on the benefits, risks, and side-effects involved in the use of such substances over months and years. It concludes by making some general proposals for policy makers.

In Kenneth Einar Himma’s substantial commentary, there are a number of conceptual misunderstandings I want to get out of the way first. This will allow us to see the core of his contribution much clearer. On page 2, Himma writes about the problem of “explaining how it is that a particular phenomenal self is associated with a set of neurophysiological processes.” This philosophical question is ill posed: no one is identical to a particular phenomenal self. “Phenomenal self” must not be conflated with “me.” Under SMT, phenomenal selves, in standard situations, are highly specific forms of representational content. They are not particulars in an ontological sense. First, Himma introduces the notion of a “mental subject,” without giving any defining characteristics. He then proceeds to make a strong claim about conceptual necessity, presenting it as selfevident without an independent argument: “…it is not conceptually possible for a conscious mental state to occur that is not instantiated by a mental subject”. I must admit that I do not have this modal intuition, the point is not self-evident to me.

The representational dynamics of the brain is a subsymbolic process, and it has to be conceived as an "agent-free" type of dynamical self-organization. However, in generating a coherent internal world-model, the brain decomposes target space in a certain way. In doing so, it defines an "ontology": to have an ontology is to interpret a world. In this paper we argue that the brain, viewed as a representational system aimed at interpreting the world, possesses an ontology too. It decomposes target space in a way that exhibits certain invariances, which in turn are functionally significant. A challenge for empirical research is to determine which are the functional regularities guiding this decomposition process. What are the explicit and implicit assumptions about the structure of reality, which at the same time shape the causal profile of the brain's motor output and the representational deep structure of the conscious mind arising from it (its "phenomenal output")? How do they constrain high-level phenomena like conscious experience, the emergence of a first-person perspective, or social cognition? By reviewing a series of neuroscientific results, we focus on the contribution the motor system makes to this process. As it turns out, the motor system constructs goals, actions, and intending selves as basic constituents of the world it interprets. It does so by assigning a single, unified causal role to them. Empirical evidence now clearly shows how the brain actually codes movements and action goals in terms of multimodal representations of organism-object relations. Under a representationalist analysis, this process can be interpreted as an internal representation of the intentionality relation itself. We try to show how such a more complex form of representational content, once it is in place, can later function as the building block for social cognition and a for more complex, consciously experienced representation of the first-person perspective as well. The motor system may therefore play a decisive role in understanding how the functional ontology of the human brain could be gradually extended into the subjective and social domains.

The article presents a critical survey of the philosophical discussion of the mind-body-problem since the collapse of Rylean behaviourism. The major theories (identity theories, supervenience, emergentist materialism, dualist interactionism and functionalism) are sketched and briefly evaluated with regard to their advantages and disadvantages. The conclusion is that no satisfactory theory about the relation between mental and neurophysiological states exists today, but considerable progress has been made regarding the contours of this cluster of problems. A catalogue of criteria which every future theory concerning the mind-body problem must fulfill is given at the end.

differences between dreaming and waking consciousness as well. In this chapter, we will argue that these differences mainly concern the subjective quality of the dreaming experience. The interesting question, from a philosophical point of view, is not so much whether or not dreams are conscious experiences at all. Rather, one must ask in what sense dreams can be considered as conscious experiences, and what happens to the experiential subject during the dream state. Finally, in order to arrive at a more differentiated understanding of dream consciousness, we will contrast our analysis of ordinary dreams with lucid dreams, as well as with the varying degrees of lucidity and cognitive clarity seen in semi-lucid and prelucid dreams

Let me begin by focusing on the long list of agreements between the Dan Zahavi and me. As he is such a careful and scholarly author, there are almost no misunderstandings to get out of the way first. At the beginning of section 2, there is a conflation of different concepts of possibility. If we grant that imaginability is conceivability, if we pass over “practical” possibility as a non-defined term, and grant that by “physically” possible Zahavi very likely means “nomologically” possible, it still would present a major step to say that something is conceptually or metaphysically possible. Not everything that is logically or conceptually possible is metaphysically possible as well—metaphysically possible worlds have to be interpreted as a subset of logically possible worlds. How this can be done is a subject of intense and highly technical debates in current philosophy of mind. We cannot possibly enter this debate here, but let me just point out how, for instance, Zahavi’s remarks in the second paragraph of page 4 rest on a conflation between nomological and logical possibility.

Of all the current philosophical attempts to rescue the concept of “self” by working out a weaker version, one that does not imply an ontological substance or an individual in the metaphysical sense, Marcello Ghin’s is clearly my favorite. His reconstruction of the original theory is absolutely accurate and without any major misunderstandings. Enriching the concept of a “SMT-system” with the notions of “autocatalysis” and “self- sustainment,” and adding the intriguing idea that we are systems reflecting these processes on a new level of complexity, namely with the help of an integrated PSM on the level of conscious experience, seems the way to go if one wants to keep the concept of “self.” I have great difficulties in writing a reply to Ghin’s commentary, simply because I agree with so much in it. Let us see where his approach leads us

This metatheoretical paper develops a list of new research targets by exploring particularly promising interdisciplinary contact points between empirical dream research and philosophy of mind. The central example is the MPS-problem. It is constituted by the epistemic goal of conceptually isolating and empirically grounding the phenomenal property of “minimal phenomenal selfhood,” which refers to the simplest form of self-consciousness. In order to precisely describe MPS, one must focus on those conditions that are not only causally enabling, but strictly necessary to bring it into existence. This contribution argues that research on bodiless dreams, asomatic out-of-body experiences, and full-body illusions has the potential to make decisive future contributions. Further items on the proposed list of novel research targets include differentiating the concept of a “first-person perspective” on the subcognitive level; investigating relevant phenomenological and neurofunctional commonalities between mind-wandering and dreaming; comparing the functional depth of embodiment across dream and wake states; and demonstrating that the conceptual consequences of cognitive corruption and systematic rationality deficits in the dream state are much more serious for philosophical epistemology (and, perhaps, the methodology of dream research itself) than commonly assumed. The paper closes by specifying a list of potentially innovative research goals that could serve to establish a stronger connection between dream research and philosophy of mind.