Here, we argue that any neurobiological theory based on an experience/function division cannot be empirically confirmed or falsified and is thus outside the scope of science. A ‘perfect experiment’ illustrates this point, highlighting the unbreachable boundaries of the scientific study of consciousness. We describe a more nuanced notion of cognitive access that captures personal experience without positing the existence of inaccessible conscious states. Finally, we discuss the criteria necessary for forming and testing a falsifiable theory of consciousness.

A broad range of evidence regarding the functional organization of the vertebrate brain – spanning from comparative neurology to experimental psychology and neurophysiology to clinical data – is reviewed for its bearing on conceptions of the neural organization of consciousness. A novel principle relating target selection, action selection, and motivation to one another, as a means to optimize integration for action in real time, is introduced. With its help, the principal macrosystems of the vertebrate brain can be seen to form (...) a centralized functional design in which an upper brain stem system organized for conscious function performs a penultimate step in action control. This upper brain stem system retained a key role throughout the evolutionary process by which an expanding forebrain – culminating in the cerebral cortex of mammals – came to serve as a medium for the elaboration of conscious contents. This highly conserved upper brainstem system, which extends from the roof of the midbrain to the basal diencephalon, integrates the massively parallel and distributed information capacity of the cerebral hemispheres into the limited-capacity, sequential mode of operation required for coherent behavior. It maintains special connective relations with cortical territories implicated in attentional and conscious functions, but is not rendered nonfunctional in the absence of cortical input. This helps explain the purposive, goal-directed behavior exhibited by mammals after experimental decortication, as well as the evidence that children born without a cortex are conscious. Taken together these circumstances suggest that brainstem mechanisms are integral to the constitution of the conscious state, and that an adequate account of neural mechanisms of conscious function cannot be confined to the thalamocortical complex alone. (Published Online May 1 2007) Key Words: action selection; anencephaly; central decision making; consciousness; control architectures; hydranencephaly; macrosystems; motivation; target selection; zona incerta. (shrink)

How can we disentangle the neural basis of phenomenal consciousness from the neural machinery of the cognitive access that underlies reports of phenomenal consciousness? We can see the problem in stark form if we ask how we could tell whether representations inside a Fodorian module are phenomenally conscious. The methodology would seem straightforward: find the neural natural kinds that are the basis of phenomenal consciousness in clear cases when subjects are completely confident and we have no reason to doubt their (...) authority, and look to see whether those neural natural kinds exist within Fodorian modules. But a puzzle arises: do we include the machinery underlying reportability within the neural natural kinds of the clear cases? If the answer is ‘Yes’, then there can be no phenomenally conscious representations in Fodorian modules. But how can we know if the answer is ‘Yes’? The suggested methodology requires an answer to the question it was supposed to answer! The paper argues for an abstract solution to the problem and exhibits a source of empirical data that is relevant, data that show that in a certain sense phenomenal consciousness overflows cognitive accessibility. The paper argues that we can find a neural realizer of this overflow if assume that the neural basis of phenomenal consciousness does not include the neural basis of cognitive accessibility and that this assumption is justified by the explanations it allows. (shrink)

Consciousness is a mongrel concept: there are a number of very different "consciousnesses." Phenomenal consciousness is experience; the phenomenally conscious aspect of a state is what it is like to be in that state. The mark of access-consciousness, by contrast, is availability for use in reasoning and rationally guiding speech and action. These concepts are often partly or totally conflated, with bad results. This target article uses as an example a form of reasoning about a function of "consciousness" based on (...) the phenomenon of blindsight. Some information about stimuli in the blind field is represented in the brains of blindsight patients, as shown by their correct "guesses," but they cannot harness this information in the service of action, and this is said to show that a function of phenomenal consciousness is somehow to enable information represented in the brain to guide action. But stimuli in the blind field are BOTH access-unconscious and phenomenally unconscious. The fallacy is: an obvious function of the machinery of access-consciousness is illicitly transferred to phenomenal consciousness. (shrink)

In What the Body Commands, Colin Klein proposes and defends a novel theory of pain. Klein argues that pains are imperative; they are sensations with a content, and that content is a command to protect the injured part of the body. He terms this view "imperativism about pain," and argues that imperativism can account for two puzzling features of pain: its strong motivating power and its uninformative nature. Klein argues that the biological purpose of pain is homeostatic; like hunger and (...) thirst, pain helps solve a challenge to bodily integrity. It does so by motivating you to act in ways that help the body recover. If you obey pain's command, you get better. He develops his account to handle a variety of pain phenomena and applies it to solve a number of historically puzzling cases. Klein's intent is to defend the imperativist view in a pure form -- without requiring pain to represent facts about the world.Klein presents a model of imperative content showing that intrinsically motivating sensations are best understood as imperatives, and argues that pain belongs to this class. He considers the distinction between pain and suffering; explains how pain motivates; addresses variations among pains; and offers an imperativist account of maladaptive pains, pains that don't appear to hurt, masochism, and why pain feels bad. (shrink)

This much-anticipated book is a detailed elaboration and defense of Levine’s influential claim that there is an “explanatory gap” between the mental and the physical.

The position advanced in this paper is that the bedrock of emotional feelings is contained within the evolved emotional action apparatus of mammalian brains. This dual-aspect monism approach to brain–mind functions, which asserts that emotional feelings may reflect the neurodynamics of brain systems that generate instinctual emotional behaviors, saves us from various conceptual conundrums. In coarse form, primary process affective consciousness seems to be fundamentally an unconditional “gift of nature” rather than an acquired skill, even though those systems facilitate skill (...) acquisition via various felt reinforcements. Affective consciousness, being a comparatively intrinsic function of the brain, shared homologously by all mammalian species, should be the easiest variant of consciousness to study in animals. This is not to deny that some secondary processes cannot be evaluated in animals with sufficiently clever behavioral learning procedures, as with place-preference procedures and the analysis of changes in learned behaviors after one has induced re-valuation of incentives. Rather, the claim is that a direct neuroscientific study of primary process emotional/affective states is best achieved through the study of the intrinsic , albeit experientially refined, emotional action tendencies of other animals. In this view, core emotional feelings may reflect the neurodynamic attractor landscapes of a variety of extended trans-diencephalic, limbic emotional action systems—including SEEKING, FEAR, RAGE, LUST, CARE, PANIC, and PLAY. Through a study of these brain systems, the neural infrastructure of human and animal affective consciousness may be revealed. Emotional feelings are instantiated in large-scale neurodynamics that can be most effectively monitored via the ethological analysis of emotional action tendencies and the accompanying brain neurochemical/electrical changes. The intrinsic coherence of such emotional responses is demonstrated by the fact that they can be provoked by electrical and chemical stimulation of specific brain zones—effects that are affectively laden. For substantive progress in this emerging research arena, animal brain researchers need to discuss affective brain functions more openly. Secondary awareness processes, because of their more conditional, contextually situated nature, are more difficult to understand in any neuroscientific detail. In other words, the information-processing brain functions, critical for cognitive consciousness, are harder to study in other animals than the more homologous emotional/motivational affective state functions of the brain. (shrink)

An adequate understanding of ‘the self’ and/or ‘primary-process consciousness’ should allow us to explain how affective experiences are created within the brain. Primitive emotional feelings appear to lie at the core of our beings, and the neural mechanisms that generate such states may constitute an essential foundation process for the evolution of higher, more rational, forms of consciousness. At present, abundant evidence indicates that affective states arise from the intrinsic neurodynamics of primitive self-centred emotional and motivational systems situated in subcortical (...) regions of the brain. Accordingly, a neural understanding of ‘the self’ may arise from a study of how various biological value-coding systems converge and interact with coherent brainstem representations of the body and nearby attentional/waking systems of the brain. Affective feelings may be caused by the neurodynamics of basic emotional circuits interacting with the neural schema of bodily action plans. One key brain area where such interactions occur is found within centromedial diencephalic midbrain areas such as the periventricular and periaqueductal gray and nearby tectal and tegmental zones. Here I will envision that a Simple Ego-type Life Form is instantiated in those circuits The ability of this ’primal SELF’ to resonate with primitive emotional values may help yield the raw subjectively experienced feelings of pleasure, lust, anger, hunger, desire, fear, loneliness and so forth. A study of such systems is a reasonable starting point for the neurological analysis of affective feelings, which may lie at the periconscious core of all other forms of animal consciousness. If such a neurodynamic process was an essential neural preadaptation for the emergence of higher levels of consciousness, it may help us close the explanatory gap between brain circuit states and the psychological nature of affective feelings. Thereby, it may also help us conceptualize the nature of psychological binding within higher forms of consciousness in new ways. (shrink)

Our aim in this reply is to defend Global Workspace theory (GWT) from the challenge of Block's article. We argue that Block's article relies on an outdated and imprecise concept of access, and perpetuates a common misunderstanding of GWT that conflates the global workspace with working memory. In the light of the relevant clarifications, Block's conclusion turns out to be unwarranted, and the basic tenets of GWT emerge unscathed.

Can we really make sense of the idea (implied by Block's treatment) that there can be isolated islets of experience that are not even potentially available as fodder for a creature's conscious choices and decisions? The links between experience and the availability of information to guide conscious choice and inform reasoned action may be deeper than the considerations concerning (mere) reportability suggest.