The neural correlate of (un)awareness: lessons from the vegetative state

Consciousness has two main components: wakefulness and awareness. The vegetative state is characterized by wakefulness without awareness. Recent functional neuroimaging results have shown that some parts of the cortex are still functioning in 'vegetative' patients. External stimulation, such as a painful stimulus, still activates 'primary' sensory cortices in these patients but these areas are functionally disconnected from 'higher order' associative areas needed for awareness. Such studies are disentangling the neural correlates of the vegetative state from the minimally conscious state, and have major clinical consequences in addition to empirical importance for the understanding of consciousness.     

Merleau–Ponty on the Body

The French philosopher Maurice Merleau–Ponty claims that there are two distinct ways in which we can understand the place of an object when we are visually apprehending it. The first involves an intentional relation to the object that is essentially cognitive or can serve as the input to cognitive processes; the second irreducibly involves a bodily set or preparation to deal with the object. Because of its essential bodily component, Merleau–Ponty calls this second kind of understanding 'motor intentional'. In this paper I consider some phenomenological, conceptual, and cognitive neuro–scientific results that help to elucidate and defend the distinction between intentional and motor intentional activity. I go on to argue that motor intentional activity has a logical structure that is essentially distinct from that of the more canonical kinds of intentional states. In particular, the characteristic logical distinction between the content and the attitude of an intentional state does not carry over to the motor intentional case.     

Brain signals do not demonstrate unconscious decision making: An interpretation based on graded conscious awareness

Neuroscientific studies have shown that brain activity correlated with a decision to move can be observed before a person reports being consciously aware of having made that decision (e.g., Libet, Gleason, Wright, & Pearl, 1983; Soon, Brass, Heinze, & Haynes, 2008). Given that a later event (i.e., conscious awareness) cannot cause an earlier one (i.e., decision-related brain activity), such results have been interpreted as evidence that decisions are made unconsciously (e.g., Libet, 1985). We argue that this interpretation depends upon an all-or-none view of consciousness, and we offer an alternative interpretation of the early decision-related brain activity based on models in which conscious awareness of the decision to move develops gradually up to the level of a reporting criterion. Under this interpretation, the early brain activity reflects sub-criterion levels of awareness rather than complete absence of awareness and thus does not suggest that decisions are made unconsciously.     

Consciousness: a neurological perspective

Consciousness is a state so essentially entwined with human experience, yet so difficult to conceptually define and measure. In this article, we explore how a bidimensional model of consciousness involving both level of arousal and subjective awareness of the contents of consciousness can be used to differentiate a range of healthy and altered conscious states. These include the different sleep stages of healthy individuals and the altered states of consciousness associated with neurological conditions such as epilepsy, vegetative state and coma. In particular, we discuss how arousal and awareness are positively correlated in normal physiological states with the exception of REM sleep, while a disturbance in this relationship is characteristic of vegetative state, minimally conscious state, complex partial seizures and sleepwalking.     

A Generative System for Intentional Action?

It has been proposed that intentional actions are supplied by a generative system of the sort described by Chomsky for language. In this paper I aim to provide a closer analysis of this claim for the sake of conceptual clarification. To this end, I will first clarify what is involved in the thesis of a structural analogy between language and action, and then I will consider what kind of evidence there seems to be in favour of the thesis of a neurobiological identity. On this basis, I will subsequently focus on two definitional issues. The first is whether, as the claim of a generative system for intentional action suggests, humans may perform an infinite number of possible actions. The second is whether, as the claim of a generative system for intentional action suggests, what is at issue is conscious planning of action and therefore controlled processing.     

What is it to lose hope?

This paper addresses the phenomenology of hopelessness. I distinguish two broad kinds of predicament that are easily confused: ‘loss of hopes’ and ‘loss of hope’. I argue that not all hope can be characterised as an intentional state of the form ‘I hope that p’. It is possible to lose all hopes of that kind and yet retain another kind of hope. The hope that remains is not an intentional state or a non-intentional bodily feeling. Rather, it is a ‘pre-intentional’ orientation or ‘existential feeling’, by which I mean something in the context of which certain kinds of intentional state, including intentional hope, are intelligible. I go on to discuss severe depression, lack of aspiration, demoralisation and loss of trust in the world, in order to distinguish some qualitatively different forms that loss of hope can take.     

Is the sense of bodily ownership related to pre-reflective bodily awareness? A reply to Kuhle

There are two ways in which we are aware of our bodies: reflectively, when we attend to them, and pre-reflectively, a kind of marginal awareness that pervades regular experience. However, there is an inherent issue with studying bodily awareness of the pre-reflective kind: given that it is, by definition, non-observational, how can we observe it? Kuhle claims to have found a way around this problem—we can study it indirectly by investigating an aspect of reflective bodily awareness: the sense of bodily ownership. Unfortunately, I argue, there is little reason to believe a relationship between pre-reflective bodily awareness and the sense of bodily ownership exists. Until more work is done, pre-reflective bodily awareness remains beyond our empirical grasp.     

The thalamic dynamic core theory of conscious experience

I propose that primary conscious awareness arises from synchronized activity in dendrites of neurons in dorsal thalamic nuclei, mediated particularly by inhibitory interactions with thalamic reticular neurons. In support, I offer four evidential pillars: (1) consciousness is restricted to the results of cortical computations; (2) thalamus is the common locus of action of brain injury in vegetative state and of general anesthetics; (3) the anatomy and physiology of the thalamus imply a central role in consciousness; (4) neural synchronization is a neural correlate of consciousness.     

Confronting Many‐Many Problems: Attention and Agentive Control

I argue that when perception plays a guiding role in intentional bodily action, it is a necessary part of that action. The argument begins with a challenge that necessarily arises for embodied agents, what I call the Many‐Many Problem. The Problem is named after its most common case where agents face too many perceptual inputs and too many possible behavioral outputs. Action requires a solution to the Many‐Many Problem by selection of a specific linkage between input and output. In bodily action the agent perceptually selects, and in this way perceptually attends to, relevant information so as to guide the execution of specific movements. Since perceptual attention is a necessary part of solving the Many‐Many Problem, it is a necessary part of bodily action. Indeed, the process of implementing a solution to the Many‐Many Problem, as constrained by the agent's motivational state, just is the agent's performing an intentional bodily action in the relevant way.     

AGENCY AND AWARENESS

I focus on the idea that if, as a result of lacking any conscious goal related to X‐ing and any conscious anticipation or awareness of X‐ing, one could sincerely reply to the question ‘Why are you X‐ing?’ with ‘I didn't realize I was doing that,’ then one's X‐ing is not intentional. My interest is in the idea interpreted as philosophically substantial (rather than merely stipulative) and as linked to the familiar view that there is a major difference, relative to the exercise of agential control, between acting on a conscious goal (even one the agent is not actively thinking about) and acting on a non‐conscious goal (about which the sincerely ‘clueless’ response ‘I didn't realize I was doing that’ could be provided). After raising some doubts about the target idea, I consider the two most promising lines of defence. I argue that neither is convincing, and that we should reject the suggestion that the idea is properly accepted as a matter of common sense. Even absent any conscious goal related to X‐ing and any conscious anticipation or awareness of X‐ing, there is room for counting X‐ing as intentional if X‐ing is, or is appropriately related to, a non‐conscious goal.     

The body in action

This article is about how to describe an agent’s awareness of her bodily movements when she is aware of executing an action for a reason. Against current orthodoxy, I want to defend the claim that the agent’s experience of moving has an epistemic place in the agent’s awareness of her own intentional action. In “The problem,” I describe why this should be thought to be problematic. In “Motives for denying epistemic role,” I state some of the main motives for denying that bodily awareness has any epistemic role to play in the content of the agent’s awareness of her own action. In “Kinaesthetic awareness and control,” I sketch how I think the experience of moving and the bodily sense of agency or control are best described. On this background, I move on to present, in “Arguments for epistemic role,” three arguments in favour of the claim that normally the experience of moving is epistemically important to one’s awareness of acting intentionally. In the final “Concluding remarks,” I round off by raising some of the worries that motivated the denial of my claim in the first place.

Bipartism and the Phenomenology of Content

Bipartism is the common view that the nature of an intentional state can be wholly explained in terms of (a) its horizontal relations with other such states (as well as peripheral inputs and outputs); and (b) its vertical relations with the world. Extrapolating from Nagel, I try to show that bipartism is fundamentally mistaken. Some intentional states are conscious states, and thus there is something it is like to be in them. This phenomenology is of a piece with such states' interpretability: to know what it is like to be X at least involves being able to interpret X's conscious intentional states. But a bi-partist account of an intentional state is not, by itself, interpretational. So bipartist accounts, at least of conscious intentional states, are incomplete: they fail to capture their phenomenology.     

Mind and movement

Voluntary movements embrace both intentional, conscious and post-intentional, largely automatic processes. Here, we examine these types of processes and the relations between them during preparation and execution of voluntary movements. First, a general overview is given about how intentional and post-intentional components are interleaved to enable successful control of purposeful movements. Second, we briefly describe some post-intentional processes that are triggered by preceding intentions. Third, we discuss findings according to which such post-intentional processes or their results can become accessible to conscious awareness. Under such conditions, automatic and conscious processes can co-occur. We show that intentional interventions into post-intentional processes can be overridden by automatic processes, can interfere with automatic processes and can be independent so that their outcomes add to those of automatic processes.     

Higher-order theories of consciousness and what-it-is-like-ness

Ambitious higher-order theories of consciousness aim to account for conscious states when these are understood in terms of what-it-is-like-ness. This paper considers two arguments concerning this aim, and concludes that ambitious theories fail. The misrepresentation argument against HO theories aims to show that the possibility of radical misrepresentation—there being a HO state about a state the subject is not in—leads to a contradiction. In contrast, the awareness argument aims to bolster HO theories by showing that subjects are aware of all their conscious states. Both arguments hinge on how we understand two related notions which are ubiquitous in discussions of consciousness: those of what-it-is-like-ness and there being something it is like for a subject to be in a mental state. This paper examines how HO theorists must understand the two crucial notions if they are to reject the misrepresentation argument but assert the awareness argument. It shows that HO theorists can and do adopt an understanding—the HO reading—which seems to give them what they want. But adopting the HO reading changes the two arguments. On this reading, the awareness argument tells us nothing about those states there is something it is like to be in, and so offers no support to ambitious HO theories. And to respond to the misrepresentation understood according to the HO reading is to simply ignore the argument presented, and so to give no response at all. As things stand, we should deny that HO theories can account for what-it-is-like-ness.     

Mental states,processes, and conscious intent in Libet's experiments

The meaning and significance of Benjamin Libet's studies on the timing of conscious will have been widely discussed, especially by those wishing to draw sceptical conclusions about conscious agency and free will. However, certain important correctives for thinking about mental states and processes undermine the apparent simplicity and logic of Libet's data. The appropriateness, relevance and ecological validity of Libet's methods are further undermined by considerations of how we ought to characterise intentional actions, conscious intention, and what it means to act with conscious intent. Recent extensions of Libet's paradigm using fMRI and decision-based tasks suffer from similar limitations. The result is that these sorts of laboratory studies of isolated, trivial, decontextualized bodily movements, in a context of extended (conscious) intentional experimental participation and cooperation, are of dubious and potentially misleading relevance to the study of agency.     

Propositional Attitudes and Embodied Skills in the Philosophy of Action

Propositionalism in the philosophy of action is the popular view that intentional actions are bodily movements caused and rationalized by certain ‘internal’ propositional attitude states that constitute the agent's perspective. I attack propositionalism's background claim that the genuinely mental/cognitive dimension of human action resides solely in some range of ‘internal’ agency‐conferring representational states that causally trigger, and thus are always conceptually disentangle‐able from, bodily activity itself. My opposing claim, following Ryle, Wittgenstein, and others, is that mentality and intentionality can be constitutively implicated in bodily actions themselves, as exercises of a distinctive form of embodied practical understanding. I attempt to show this by attending to the fine‐grained contours of various skillful actions.     

The Feeling of Bodily Ownership

In certain startling neurological and psychiatric conditions, what is ordinarily most intimate and familiar to us—our own body—can feel alien. For instance, in cases of somatoparaphrenia subjects misattribute their body parts to others, while in cases of depersonalization subjects feel estranged from their bodies. These ownership disorders thus appear to consist in a loss of any feeling of bodily ownership, the felt sense we have of our bodies as our own. Against this interpretation of ownership disorders, I defend Sufficiency, the thesis that every experience of bodily awareness suffices for a feeling of bodily ownership. Since Sufficiency conflicts with a face-value interpretation of these ownership disorders, the burden is on me to explain away the apparent tension. To do so, I identify and correct what I believe to be the fundamental mistake in the extant literature on the feeling of bodily ownership, namely the tendency to treat the notion of a feeling of bodily ownership as a single psychological construct. Instead, I distinguish the feeling of minimal ownership, the first-personal character of bodily awareness, from the feeling of affective ownership, the distinctive type of felt concern we have for our bodies. I motivate this distinction by raising the disownership puzzle, the fact that subjects suffering from ownership disorders display an ambiguous set of symptoms, arguing the distinction I draw between minimal and affective ownership is just what is required to resolve the puzzle.     

Intentional psychologism

In the past few years, a number of philosophers (notably, Siewert, C. (The significance of consciousness. Princeton: Princeton University Press, 1998); Horgan and Tienson (Philosophy of mind: Classical and contemporary readings, Oxford University Press, 2002, pp. 520–533); Pitt 2004) have maintained the following three theses: (1) there is a distinctive sort of phenomenology characteristic of conscious thought, as opposed to other sorts of conscious mental states; (2) different conscious thoughts have different phenomenologies; and (3) thoughts with the same phenomenology have the same intentional content. The last of these three claims is open to at least two different interpretations. It might mean that the phenomenology of a thought expresses its intentional content, where intentional content is understood as propositional, and propositions are understood as mind-and language-independent abstract entities (such as sets of possible worlds, functions from possible worlds to truth-values, structured n-tuples of objects and properties, etc.). And it might mean that the phenomenology of a thought is its intentional content—that is, that the phenomenology of a thought, like the phenomenology of a sensation, constitutes its content. The second sort of view is a kind of psychologism. Psychologistic views hold that one or another sort of thing—numbers, sentences, propositions, etc.—that we can think or know about is in fact a kind of mental thing. Since Frege, psychologism has been in bad repute among analytic philosophers. It is widely held that Frege showed that such views are untenable, since, among other things, they subjectivize what is in fact objective, and, hence, relativize such things as consistency and truth to the peculiarities of human psychology. The purpose of this paper is to explore the consequences of the thesis that intentional mental content is phenomenological (what I call “intentional psychologism”) and to try to reach a conclusion about whether it yields a tenable view of mind, thought and meaning. I believe the thesis is not so obviously wrong as it will strike many philosophers of mind and language. In fact, it can be defended against the standard objections to psychologism, and it can provide the basis for a novel and interesting account of mentality.