Online research in philosophy

Higher-order theories of consciousness, such as those of Armstrong, Rosenthal and Lycan, typically distinguish sharply between consciousness and phenomenal character, or qualia. The higher-order states posited by these theories are intended only as explanations of consciousness, and not of qualia. In this paper I argue that the positing of higher-order perceptions may help to explain qualia. If we are realists about qualia, conceived as those intrinsic properties of our experience of which we are introspectibly aware, then higher-order perception might have an explanatory role as the means by which we are aware of these properties. This would also allow us to treat qualia as the inner appearances resulting from inner perceptions, and therefore to treat them as intentional objects.

For a theory of phenomenal consciousness, the real issue is not that between vehicle and process, but between naturalistic and deconstructive theories. Most current naturalistic theories combine a hypothesis about the neural correlate of consciousness with a subsequent naturalistic proposal about how to close the explanatory gap. Deconstructive theories use theses about the neural correlate of consciousness only to motivate and support their claim that the “hard problem” of consciousness is a pseudo-problem which is not to be solved, but rather dissolved on non-naturalistic grounds. O'Brien & Opie present a hypothesis concerning the neural correlate of consciousness, but no genuine strategy to close the explanatory gap. Their theory can, however, contribute to the success of a deconstructive theory of PC.

Phenomenal consciousness is the property mental states, events, and processes have when, and only when, there is something it is like for their subject to undergo them, or be in them. What it is like to have a conscious experience is customarily referred to as the experience’s phenomenal character. Theories of consciousness attempt to account for this phenomenal character. This article surveys the currently prominent theories, paying special attention to the various attempts to explain a state’s phenomenal character in terms of its representational content.

The terminology surrounding the dispute between higher-order and first-order theories of consciousness is piled so high that it sometimes obscures the view. When the debris is cleared away, there is a real prospect.

p0005 The term ‘consciousness’ is used in several ways: to describe a person or other creature as being awake and sentient, to describe a person or other creature as being ‘aware of ’ something, and to refer to a property of mental states, such as perceiving, feeling, and thinking, that distinguishes those states from unconscious mental states. Distinguishing these different concepts of consciousness is crucial in evaluating the major theories of what it is for a state to be conscious. Among those are first-order theories, on which a mental state is conscious if being in that state results in one’s being conscious of something; global-workspace theories, on which a state is conscious if it’s widely available for mental processing; inner-sense theories, on which a state is conscious if one senses or perceives that state by way of a special inner faculty; and higher-orderthought theories, on which a state is conscious if one is aware of that state by having a thought about it. We will consider the advantages and shortcomings of these theories and variants of them.

The explanatory gap . Consciousness is a mystery. No one has ever given an account, even a highly speculative, hypothetical, and incomplete account of how a physical thing could have phenomenal states. (Nagel, 1974, Levine, 1983) Suppose that consciousness is identical to a property of the brain, say activity in the pyramidal cells of layer 5 of the cortex involving reverberatory circuits from cortical layer 6 to the thalamus and back to layers 4 and 6,as Crick and Koch have suggested for visual consciousness. (See Crick (1994).) Still, that identity itself calls out for explanation! Proponents of an explanatory gap disagree about whether the gap is permanent. Some (e.g. Nagel, 1974) say that we are like the scientifically naive person who is told that matter = energy, but does not have the concepts required to make sense of the idea. If we can acquire these concepts, the gap is closable. Others say the gap is uncloseable because of our cognitive limitations. (McGinn, 1991) Still others say that the gap is a consequence of the fundamental nature of consciousness.

In this paper, we present an account of phenomenal consciousness. Phenomenal consciousness is experience, and the problem of phenomenal consciousness is to explain how physical processes?behavioral, neural, computational?can produce experience. Numerous thinkers have argued that phenomenal consciousness cannot be explained in functional, neural or information-processing terms (e.g. Block 1990, 1994; Chalmers 1996). Different arguments have been put forward. For example, it has been argued that two individuals could be exactly alike in functional/computational/behavioral measures, but differ in the character of their experience. Though such persons would behave in the same way, they would differ in how things felt to them (for example, red things might give rise to the experience in one that green things give rise to in the other). Similarly, it has been held that two individuals could be functionally/computationally/behaviorally alike although one of them, but not the other, is a mere zombie, that is, a robot-like creature who acts as if it has experience but is in fact phenomenally unconsciousness. For any being, it has been suggested, the question whether it has experience (is phenomenally conscious) cannot be answered by determining that it is an information-processor of this or that sort. The question is properly equivalent to the question whether there is anything it is like to be that individual (Nagel 1974). Attempts to explain consciousness in physical or information-processing terms sputter: we cannot get any explanatory purchase on experience when we try to explain it in terms of neural or computational processes. Once a particular process has been proposed as an explanation, we can then always reasonably wonder, it seems, what it is about that particular process that make it give rise to experience. Physical and computational mechanisms, it seems, require some further ingredient if they are to explain experience. This explanatory shortfall has aptly been referred to as "the explanatory gap" (Levine 1983)..

It is commonplace for both philosophers and cognitive scientists to express their allegiance to the "unity of consciousness". This is the claim that a subject’s phenomenal consciousness, at any one moment in time, is a single thing. This view has had a major influence on computational theories of consciousness. In particular, what we call single-track theories dominate the literature, theories which contend that our conscious experience is the result of a single consciousness-making process or mechanism in the brain. We argue that the orthodox view is quite wrong: phenomenal experience is not a unity, in the sense of being a single thing at each instant. It is a multiplicity, an aggregate of phenomenal elements, each of which is the product of a distinct consciousness-making mechanism in the brain. Consequently, cognitive science is in need of a multi-track theory of consciousness; a computational model that acknowledges both the manifold nature of experience, and its distributed neural basis.

There are two broad classes of empirical theories of consciousness, which I will call the biological and the functional. The biological approach is based on empirical correlations between experience and the brain. For example, there is a great deal of evidence that the neural correlate of visual experience is activity in a set of occipetotemporal pathways, with special emphasis on the infero-temporal cortex. The functionalist approach is a successor of behaviorism, the view that mentality can be seen as tendencies to emit certain behavioral outputs given certain sensory inputs. The trouble with behaviorism is that it did not allow that mental states were causes and effects, but functionalists do allow this. They characterize consciousness in terms of its causal role: the causal influence on it from inputs and other mental states, and its causal efficacy with respect to other mental states and behavior. The central idea of functionalism is a proposal about the concept of consciousness, but scientific functionalists have filled the view in with empirical details—the idea is that a representation is conscious if it is broadcast in a global neuronal workspace. (See the article by Dehaene in Dehaene, 2001.) The functional approach says consciousness is a role, whereas the biological approach says consciousness is a realizer of that role. For example, one could take solubility to be a role—dissolving in certain circumstances—or, as with the biological view of consciousness, the physico-chemical configuration that has that role. The..