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The Character of Consciousness

DAVID CHALMERS
2010

There is at least some plausibility in the idea that the concepts of consciousness and states of consciousness are fundamentally holistic rather than atomistic

The Problems of Consciousness
  • There is nothing that we know more intimately than conscious experience, but there is nothing that is harder to explain.
  • The really hard problem of consciousness is the problem of experience.
  • It is widely agreed that experience arises from a physical basis, but we have no good explanation of why and how it so arises. An organism is conscious if there is something it is like to be that organism.
  • The easy problems are easy precisely because they concern the explanation of cognitive abilities and functions. Questions about the performance of functions are well suited to reductive explanation. When it comes to conscious experience, what makes the hard problem hard and almost unique is that it goes beyond problems about the performance of functions. There is an explanatory gap between the functions and experience. The emergence of experience goes beyond what can be derived from physical theory.
  • Experience may arise from the physical, but it is not explained by the physical.
  • Reductive methods are successful in most domains because what needs explaining in those domains are structures and functions, and these are the kinds of thing that a physical account can entail. A remarkable number of phenomena have turned out to be explicable wholly in terms of entities simpler than themselves. Sometimes an entity has to be taken as fundamental as it is not explained in terms of anything simpler. A theory of consciousness should take experience as fundamental.
  • Conscious experience is not directly observable in an experimental context, so we cannot generate data about the relationship between physical processes and experience at will.
  • A nonreductive theory of consciousness will consist of a number of psychophysical principles, principles that connect the properties of physical processes to the properties of experience. The principles for developing and constraining a theory of consciousness include:
    • The Principle of Structural Coherence is a principle of coherence between the structure of consciousness and the structure of awareness. The contents of awareness are to be understood as those information contents that are accessible to central systems and brought to bear in a widespread way in the control of behavior. Awareness is a purely functional notion, but it is nevertheless intimately linked to conscious experience. Wherever there is conscious experience, there is some corresponding information in the cognitive system that is available in the control of behavior. There is a direct correspondence between consciousness and awareness. It is this isomorphism between the structures of consciousness and awareness that constitutes the principle of structural coherence. It is not a logically necessary principle, as after all we can imagine all of the information processing occurring without any experience at all.
    • The Principle of Organizational Invariance states that any two systems with the same fine-grained functional organization will have qualitatively identical experiences. Any two systems with the same fine-grained functional organization will have qualitatively identical experiences. The only physical properties directly relevant to the emergence of experience are organizational properties.
    • The Double-Aspect Theory of Information principle stems from the observation that there is a direct isomorphism between certain physically embodied information spaces and certain phenomenal (or experiential) information spaces. Information (or at least some information) has two basic aspects, a physical aspect and a phenomenal aspect. Experience arises by virtue of its status as one aspect of information, when the other aspect is found embodied in physical processing. Phenomenal properties are the internal aspect of information.
  • Most existing theories of consciousness either deny the phenomenon, explain something else, or elevate the problem to an eternal mystery.
The Science of Consciousness
  • The task of a science of consciousness is to systematically integrate two key classes of data into a scientific framework: third-person data, or data about behavior and brain processes, and first-person data, or data about subjective experience. First-person data are irreducible to third-person data and vice versa.
  • We can expect systematic bridging principles to underlie and explain the covariation between third-person data and first-person data. A theory of consciousness will ultimately be a theory of these principles.
  • Experimental results suggest a strong association between the presence or absence of subjective experience and the presence or absence of an associated functional capacity—a systematic link between first-person and third-person data.
  • A neural correlate of consciousness (NCC) can be characterized as a minimal neural system that is directly associated with states of consciousness.
  • If a technology is eventually developed that allows for noninvasive monitoring of neuron-level processes in human subjects, we might expect a golden age for the science of consciousness to follow.
  • There are three obstacles involving first-person data:
    • Privacy: To others, first-person data are only indirectly available, mediated by observation of the subject’s behavior or brain processes. Access to first person data depends on the reasonable assumption that other subjects really are having conscious experiences and that by and large their verbal reports reflect these conscious experiences.
    • Methodology: Our methods for gathering first-person data are quite primitive compared with our methods for gathering third-person data. Particular difficulties arise in investigating the character of consciousness outside attention. To introspect and report this structure may well change the character of the experience. And observations may be corrupted by theory.
    • Formalisms: A final obstacle is posed by the absence of general formalisms with which first-person data can be expressed. There can be a science of consciousness as long as we accept that science can deal with first-person data and as long as we allow that verbal reports and the like can be used as an indirect guide to the first-person data about consciousness.
  • Neural Correlate of Consciousness (NCC) is a phrase is intended to refer to the neural system or systems primarily associated with conscious experience.
  • It seems reasonable to expect that we will find informative brain-based correlates of consciousness at some level of abstraction in cognitive neurobiology.
  • Consciousness is just not the sort of thing that can be measured directly. Bridging principles are implicit in the methodology for the search for the NCC.
The Metaphysics of Consciousness
  • The Explanatory Argument: Physical accounts explain at most structure and function. Explaining structure and function does not suffice to explain consciousness. Therefore no physical account can explain consciousness.
  • The Conceivability Argument: Physically identical to a conscious being but that lacks at least some of that being’s conscious states. It looks identical to a normal conscious being from the third-person perspective. It is conceivable that there are zombies. If it is conceivable that there are zombies, it is metaphysically possible that there are zombies. If it is metaphysically possible that there are zombies, then consciousness is nonphysical. Therefore consciousness is nonphysical.
  • The Knowledge Argument: there are facts about consciousness that are not deducible from physical facts. There are truths about consciousness that are not deducible from physical truths. If there are truths about consciousness that are not deducible from physical truths, then materialism is false.
  • These three sorts of arguments start by establishing an epistemic gap between the physical and the phenomenal domains. These arguments proceed by inferring an ontological gap, where ontology concerns the nature of things in the world.
  • The Epistemic Argument: There is an epistemic gap between physical and phenomenal truths. If there is an epistemic gap between physical and phenomenal truths, then there is an ontological gap, and materialism is false.
  • A type-A materialist denies the existence of the relevant sort of epistemic gap. A type-B materialist accepts the existence of an unclosable epistemic gap but denies that there is an ontological gap. A type-C materialist accepts the existence of a deep epistemic gap but holds that it will eventually be closed.
  • Materialistic views include:
    • Type-A Materialism The debate between type-A materialists and their opponents usually comes down to intuition: most centrally, the intuition that consciousness (in a nonfunctionally defined sense) exists or that there is something that needs to be explained (over and above explaining the functions).
    • Type-B Materialism If one labels these principles identities or necessities rather than laws, the view may preserve the letter of materialism, but by requiring primitive bridging principles, one sacrifices much of materialism’s spirit.
    • Type-C Materialism there is a deep epistemic gap between the physical and phenomenal domains, but it is closable in principle. We do not yet have a complete physics, so we cannot know what such a physics might explain. A complete physical description of the world must also characterize the intrinsic properties that ground these structures and relations, and once such intrinsic properties are invoked, physics will go beyond structure and dynamics in such a way that truths about consciousness may be entailed. Although unknown to us, but they are knowable in principle.
  • Nonreductionist views are:
    • Type-D Dualism holds that microphysics is not causally closed and that phenomenal properties play a causal role in affecting the physical world. Also knwon as Interactionism. The corresponding psychophysical laws run in both directions. It is widely held that science tells us that the microphysical realm is causally closed, and that there is no room for mental states to have any effects. The standard formulation of quantum mechanics, the state of the world is described by a wave function, according to which physical entities are often in a superposed state. The wave function can evolve in two ways: linear evolution by the Schrödinger equation and nonlinear collapses from superposed states. Schrödinger evolution is deterministic, but collapse is nondeterministic. Collapses occur only occasionally on measurement and leaves a door wide open for an interactionist interpretation - observation by a conscious observer.
    • Type-E Dualism holds that phenomenal properties are ontologically distinct from physical properties and that the phenomenal has no effect on the physical. Also known as Epiphenomenalism. Psychophysical laws run in one direction only—from physical to phenomenal. The physical realm is causally closed.
    • Type-F Monism is the view that consciousness is constituted by the intrinsic properties of fundamental physical entities: that is, by the categorical bases of fundamental physical dispositions. Perhaps the intrinsic properties of the physical world are themselves phenomenal properties.
  • Kripke’s metaphor: if it is possible that there is a world physically identical to our world but phenomenally different, then after God fixed the physical facts about our world, he had to do more work to fix the phenomenal facts.
  • Protophenomenal properties: properties that collectively constitute phenomenal properties when organized in the appropriate way.
  • If there is no a priori entailment from microphysical truths to phenomenal truths, then reductive explanation of the phenomenal will fail.
  • We have argued that ordinary truths about macroscopic natural phenomena are entailed a priori by the combination of physical truths, phenomenal truths, indexical truths, and a that’s-all statement. Reductive explanation requires a priori entailment.
Concepts of Consciousness
  • Experiences are paradigmatically phenomenal, characterized by what it is like to have them.
  • Certain central concepts, such as causal and mathematical concepts, are not conceptually tied to phenomenal concepts.
  • Infallibility Thesis: A direct phenomenal belief cannot be false.
  • It may be that some phenomenal states, such as fleeting or background phenomenal states, cannot be taken up into a direct phenomenal concept perhaps because they cannot be subject to the right sort of attention.
  • In no case is it possible to form a direct concept: that is, a concept whose epistemic content depends constitutively on a demonstrated property instance. It seems that only phenomenal properties can support direct concepts.
  • Acquaintance is a relation that makes possible the formation of pure phenomenal concepts, and we have seen that pure phenomenal concepts embody a certain sort of lucid understanding of phenomenal properties.
  • The basis of intentionality is poorly understood, and one might plausibly hold that a capacity for consciousness is required for intentional states.
  • Experiences do not, on their own, constitute knowledge. They play a role in justifying knowledge, and they play a role in partly constituting the beliefs that qualify as knowledge, in combination with other cognitive elements.
  • The phenomenal concept strategy cannot reconcile ontological physicalism with the explanatory gap.
The Contents of Consciousness
  • Consciousness and intentionality are perhaps the two central phenomena in the philosophy of mind.
  • Human beings are conscious beings: there is something it is like to be us. Human beings are intentional beings: we represent what is going on in the world. Correspondingly, our specific mental states, such as perceptions and thoughts, often have a phenomenal character and intentional content: they serve to represent the world.
  • Consciousness involves the instantiation of phenomenal properties. Intentionality involves the instantiation of representational properties. Intuitively, this involves representing things as being a certain way in the world.
  • Representationalism is the thesis that phenomenal properties are identical to certain representational properties.
  • Neither consciousness nor intentionality is more fundamental than the other. Rather, consciousness and intentionality are intertwined, all the way down to the ground.
  • When a belief endorses a veridical experience, the belief will be true. This need not be true in reverse: that is, it can happen that a belief endorses a falsidical experience without being false itself. An endorsing belief may make fewer commitments than the experience that it endorses, but it cannot make any commitments that are not made by the experience that it endorses.
  • Eden was a world of perfect color. But then there was a Fall. First, we ate from the Tree of Illusion. After this, objects sometimes seemed to have different colors and shapes at different times, even though there was reason to believe that the object itself had not changed. So the connection between visual experience and the world became contingent. Second, we ate from the Tree of Science. After this, we found that when we see an object, there is always a causal chain involving the transmission of light from the object to the retina and the transmission of electrical activity from the retina to the brain. This chain was triggered by microphysical properties whose connection to the qualities of our experience seemed entirely contingent.
  • At some level, perception represents our world as an Edenic world, populated by perfect colors and shapes, with objects and properties that are revealed to us directly. Eden still acts as a sort of ideal that regulates the content of our perceptual experience.
  • The Russellian hypothesis requires the Russellian constraint: all phenomenally identical color experiences attribute the same property to their object. One might hold that the properties attributed are:
    • Physical properties: something along the lines of a surface spectral reflectance.
    • Dispositional properties, involving the disposition to cause a certain sort of experience in appropriate conditions.
    • Mental properties of some sort: perhaps properties that are actually instantiated by one’s experiences or by one’s visual fields.
    • Primitive properties: simple intrinsic qualities of the sort that might have been instantiated in Eden.
  • Versions of Russellian hypothesis concerning phenomenal content might be called the physicalist, dispositionalist, projectivist, and primitivist. Each of these views has well-known problems. The physicalist view is incompatible with intuitions about spectrum inversion, according to which phenomenally identical color experiences could have represented quite different physical properties in different environments. The dispositionalist view is incompatible with the intuition that color experience attributes nonrelational properties and also has serious difficulties in individuating the relevant dispositions so that phenomenally identical experiences always attribute the same dispositions. The projectivist and primitivist views suffer from the problem that it seems that the relevant properties are not actually instantiated by external objects, with the consequence that all color experience is illusory.
  • Perceptual experiences (like linguistic expressions) have both Russellian and Fregean content. Where the Russellian content of a color experience involves a property attributed by the experience (such as a reflectance property), the Fregean content will be a mode of presentation of that property. Where Russellian content involves extensions (objects and properties), Fregean content involves conditions on extensions.
  • Fregean content, compared to physicalist Russellian content, accommodates inversion scenarios much better and also accommodates the intuition that phenomenology is internally determined.
  • The phenomenology of perceptual experience seems to have properties:
    • Relationality: Intuitively, it seems to us that when we have an experience as of a colored object, there is a certain property (intuitively, a color property) that the object seems to have.
    • Simplicity: A second objection is that Fregean contents seem to be overly complex.
    • Internal unity: A final objection is that it seems that there can be internal unity among the contents of experiences that have quite different phenomenal character. An object looks flat and when it feels flat, it looks and feels to have the same property (flatness). This commonality seems to hold in virtue of an internal relationship between the phenomenology of visual and tactile experiences.
  • The Fregean view does not seem to fully reflect the presentational phenomenology of perceptual experience: the way that it seems to directly and immediately present certain objects and properties in the world. The Fregean view of phenomenal content seems to most accurately capture our judgments about veridicality, but it is not especially phenomenologically adequate. The primitivist view of phenomenal content is the most phenomenologically adequate view, but it yields implausible consequences about veridicality.
  • The Two-stage picture of the phenomenal content of experience: The most fundamental sort of content of an experience is its Edenic content, which requires the instantiation of appropriate primitive properties. This content then determines the ordinary Fregean content of the experience: the experience is imperfectly veridical if its object has properties that match the properties attributed by the experience’s Edenic content. Our experience presents an Edenic world and thereby represents an ordinary world. The two-stage view generates a broadly dispositionalist ordinary Fregean content and a broadly physicalist ordinary Russellian content.
  • A world with respect to which our visual experience is perfectly veridical is an Edenic world. Edenic content puts relatively simple constraints on the world that involve the instantiation of perfect properties by objects in the environment.
  • There are cases in which representing a property crucially depends on contact with instances of it, but there also many cases of representation that do not work like this.
  • According to standard indirect realism, we perceive objects in the world only indirectly, in virtue of directly perceiving certain intermediate objects such as sense data, which opponents see as a "veil of perception" that cuts off perceivers from the external world.
  • The core inferential role of a perceptual experience is reflected in the pattern of judgments about veridicality and falsidicality that the subject of such an experience makes or, more strictly, in the pattern of judgments that should be rationally made.
  • The presentational phenomenology of the experience serves as direct ground for the first stage of the two-stage view (the Edenic content) and as indirect ground for the second stage (matching the Edenic content) by virtue of inferential role. The most fundamental content of perceptual experience is its Edenic content. Other aspects of content can be seen as deriving from Edenic content with the aid of the matching relation and the contribution of the environment. To understand the role of perceptual experience in representing the world, one needs to understand all of these levels of content. But to understand the phenomenology of perceptual experience in its own right, understanding Edenic content is the key.
  • The Matrix presents a version of an old philosophical fable: the brain in a vat. Someone is envatted, or is in a matrix, if he or she has a cognitive system that receives its inputs from and sends its outputs to a matrix. The matrix simulates the entire physics of a world, keeping track of every last particle throughout space and time.
  • It is not out of the question that, in the history of the universe, technology will evolve that will allow beings to create computer simulations of entire worlds.
  • Even if I am in a matrix, my world is perfectly real. A brain in a vat is not massively deluded (at least if it has always been in the vat). The hypothesis that I am envatted is not a skeptical hypothesis but a metaphysical hypothesis.
  • Where physics is concerned with the microscopic processes that underlie macroscopic reality, metaphysics is concerned with the fundamental nature of reality.
  • The Matrix Hypothesis is equivalent to a version of the following three-part metaphysical hypothesis. First, physical processes are fundamentally computational. Second, our cognitive systems are separate from physical processes but interact with them. Third, physical reality was created by beings outside physical space-time.
  • A number of hypothesis exist:
    • The Computational Hypothesis: says: microphysical processes throughout space-time are constituted by underlying computational processes. Underneath the level of quarks, electrons, and photons is a further level: the level of bits. These bits are governed by a computational algorithm.
    • The Creation Hypothesis: physical space-time and its contents were created by beings outside physical space-time.
    • The Mind-Body Hypothesis: my mind is (and has always been) constituted by processes outside physical space-time and receives its perceptual inputs from and sends its outputs to processes in physical space-time.
    • The Combination Hypothesis: that physical space-time and its contents were created by beings outside physical space-time, that microphysical processes are constituted by computational processes, and that our minds are outside physical space-time but interact with it.
    • The Metaphysical Hypothesis: like the Combination Hypothesis, this combines the Creation Hypothesis, the Computational Hypothesis, and the Mind-Body Hypothesis. It also adds the following more specific claim: the computational processes underlying physical space-time were designed by the creators as a computer simulation of a world. Computational processes could underlie physical reality, that any abstract computation that qualifies as a simulation of physical reality could play this role, and that any implementation of this computation could constitute physical reality as long as it is hooked up to our experiences in the relevant way. The immediate surroundings of our minds may well be irrelevant to the truth of most of our beliefs. What matters is the processes that our minds are connected to by perceptual inputs and motor outputs.
    • New Matrix Hypothesis: I was recently created, along with all of my memories, and was put in a newly created matrix.
    • Recent Matrix Hypothesis: For most of my life I have not been envatted, but I was recently hooked up to a matrix. This yields true beliefs about the past but false beliefs about the present, whereas the New Matrix Hypothesis yields false beliefs about the past and true beliefs about the present. The differences are tied to the fact that in the Recent Matrix Hypothesis, I really have a past existence for my beliefs to be about, and that past reality has played a role in anchoring the contents of my thoughts, which has no parallel under the new Matrix Hypothesis.
    • Local Matrix Hypothesis: I am hooked up to a computer simulation of a fixed local environment in a world. Under this hypothesis, we will have true beliefs about nearby matters but false beliefs about matters farther from home.
    • Extendible Local Matrix Hypothesis: I am hooked up to a computer simulation of a local environment in a world, which is extended when necessary depending on my movements. The extendible local matrix involves "just-in-time" simulation. This has much lower start-up costs, but it requires much more work and creativity as the simulation evolves.
    • Macroscopic Matrix Hypothesis: I am hooked up to a computer simulation of macroscopic physical processes without microphysical detail. For ease of simulation, the makers of a matrix might not bother to simulate low-level physics. Instead, they might just represent macroscopic objects in the world and their properties. They will need to make some effort to make sure that these objects behave in physically reasonable ways, and they will have to make special provisions for handling microphysical measurements.
    • God Hypothesis: Physical reality is represented in the mind of God, and our own thoughts and perceptions depend on God’s mind.
    • Evil Genius Hypothesis: I have a disembodied mind, and an evil genius is feeding me sensory inputs to give the appearance of an external world.
    • Dream Hypothesis: I am now and have always been dreaming. Many of my beliefs about my current environment are incorrect. But presumably I still have many true beliefs about the external world that are anchored in the past.
    • Chaos Hypothesis: I do not receive inputs from anywhere in the world. Instead, I have random, uncaused experiences. Through a huge coincidence, they are exactly the sort of regular, structured experiences with which I am familiar. There is no causal explanation of our experiences at all, and there is no explanation for the regularities in our experience.
  • If I am not envatted but another being is envatted, the objects that it refers to are likewise made of bits. If the envatted being is hooked up to a simulation in my computer, then the objects to which it refers are constituted by patterns of bits inside my computer. We might call these things virtual objects. From the first-person perspective, we suppose that we are in a matrix. Here, real things in our world are made of bits, though the next world up might not be made of bits. From the third-person perspective we suppose that someone else is in a matrix but that we are not. Here, real things in our world are not made of bits, but the next world down is made of bits.
  • Our ordinary conception of the macroscopic world is not easily falsified by discoveries in science and metaphysics.
The Unity of Consciousness
  • The experiences seem to be tied together in a deep way. They seem to be unified, by being aspects of a single, encompassing state of consciousness.
  • Unity thesis: Necessarily, any set of conscious states of a subject at a time is unified.
  • Objectual unity: We can say that two states of consciousness are objectually unified when they are directed at the same object. What matters is that two states are experienced as being directed at a common object.
  • Spatial unity: A related notion of unity is that of spatial unity. We can say that two conscious states are spatially unified when they represent objects as being part of the same space.
  • Subject unity: Let us say that two conscious states are subject unified when they are had by the same subject at the same time. So all of my current experiences—my perceptual experiences, my bodily sensations, my emotional experiences and conscious thoughts—are subject unified simply because they are all my experiences.
  • Subsumptive unity: involves the idea that experiences are somehow subsumed within a single state of consciousness.
  • A mental state is access conscious when a subject has a certain sort of access to the content of the state. It must be available for verbal report, for rational inference, and for the deliberate control of behavior. It is defined in terms of the causal role that the state plays within the cognitive system.
  • A mental state is phenomenally conscious when there is something it is like to be in that state.
  • Phenomenal consciousness is often taken to be the most important sort of consciousness and to be the sort of consciousness that poses the most difficulty for scientific explanation.
  • Binding Problem corresponds to objectual access unity and objectual phenomenal unity, with two distinct aspects:
    • The first is that of how a system such as the brain manages to bring together two separately represented pieces of information. This binding problem is the problem of explaining objectual access unity.
    • The second binding problem is that of explaining how it is that we perceptually experience separate pieces of information as bound together in pertaining to the same object. This is the problem of explaining objectual phenomenal unity.
  • A breakdown of access unity does not entail a breakdown in phenomenal unity.
  • The possibility remains open that split-brain subjects have a unified phenomenal field, with some sort of conjoint phenomenology subsuming each of the separate contents. It is just that the subject has pathologies of access, so that the contents of the field are accessible only singly and not jointly. But it seems quite tenable to hold that there is nevertheless a single field of consciousness at any given time, subsuming the conscious states of the subject, even if they are in certain respects mutually inaccessible.
  • It could be argued that our basic concept of consciousness is not the notion of a simple phenomenal state—what it is like to experience such-and-such at a time. Rather, our basic notion of consciousness is that of a total phenomenal state: what it is like to be a subject at a time. This yields a holistic rather than an atomistic view of consciousness. On this approach, we do not start with basic atomic states of consciousness and somehow glue them together into complex states. Rather, we start with a basic total state of consciousness and then differentiate it into simpler states and ultimately into atomic states.
  • On this view, the most basic problem with the theories of consciousness discussed in the last section is that they are atomistic rather than holistic, starting with simple states rather than total states.

These notes were taken from David's book combining a number of his papers.
Find out more at his website at consc.net


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» Consciousness and Collapse of the Wave Function 2014
» The Character of Consciousness 2010
   David Chalmers


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