Psychology of Consciousness
Representation of consciousness from the seventeenth century.
Consciousness is a term that refers to a variety of aspects of the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity; awareness; the ability to experience feelings; wakefulness; having a sense of selfhood; or the executive control system of the mind. Despite the difficulty of definition, many philosophers believe that there is a broadly shared underlying intuition about what consciousness is. As Max Velmans and Susan Schneider wrote in The Blackwell Companion to Consciousness: “Anything that we are aware of at a given moment forms part of our consciousness, making conscious experience at once the most familiar and most mysterious aspect of our lives.”[
Philosophers since the time of Descartes and Locke have struggled to comprehend the nature of consciousness and pin down its essential properties. Issues of concern in the philosophy of consciousness include whether the concept is fundamentally valid; whether consciousness can ever be explained mechanistically; whether non-human consciousness exists and if so how it can be recognized; how consciousness relates to language; and whether it may ever be possible for computers to achieve a conscious state. Perhaps the thorniest issue is whether consciousness can be understood in a way that does not require a dualistic distinction between mental and physical entities.
At one time consciousness was viewed with skepticism by many scientists, but in recent years it has been an increasingly significant topic of research. In psychology and neuroscience, the primary focus is on understanding what it means biologically and psychologically for information to be present in consciousness—that is, on determining the neural and psychological correlates of consciousness. The majority of experimental studies use human subjects and assess consciousness by asking subjects for a verbal report of their experiences (e.g., “tell me if you notice anything when I do this”). Issues of interest include phenomena such as subliminal perception, blindsight, denial of impairment, and altered states of consciousness produced by psychoactive drugs or spiritual or meditative techniques.
In medicine, consciousness is assessed by observing a patient’s arousal and responsiveness, and can be seen as a continuum of states ranging from full alertness and comprehension, through disorientation, delirium, loss of meaningful communication, and finally loss of movement in response to painful stimuli. Issues of practical concern include how the presence of consciousness can be assessed in severely ill, comatose, or anesthetized people, and how to treat conditions in which consciousness is impaired or disrupted.
Etymology and early history
The origin of the modern concept of consciousness is often attributed to John Locke‘s Essay Concerning Human Understanding, published in 1690.[ Locke defined consciousness as “the perception of what passes in a man’s own mind.” His essay had much influence on the 18th century view of consciousness, and his definition appeared in Samuel Johnson‘s celebrated Dictionary (1755).
The earliest English language uses of “conscious” and “consciousness” date back, however, to the 1500s. The English word “conscious” originally derived from the Latin conscius (con- “together” + scire “to know”), but the Latin word did not have the same meaning as our word — it meant knowing with, in other words having joint or common knowledge with another. There were, however, many occurrences in Latin writings of the phrase conscius sibi, which translates literally as “knowing with oneself”, or in other words sharing knowledge with oneself about something. This phrase had the figurative meaning of knowing that one knows, as the modern English word “conscious” does. In its earliest uses in the 1500s, the English word “conscious” retained the meaning of the Latin conscius. For example Thomas Hobbes in Leviathan wrote: “Where two, or more men, know of one and the same fact, they are said to be Conscious of it one to another.” The Latin phrase conscius sibi, whose meaning was more closely related to the current concept of consciousness, was rendered in English as “conscious to oneself” or “conscious unto oneself”. For example, Archbishop Ussher wrote in 1613 of “being so conscious unto myself of my great weakness”.[ Locke’s definition from 1690 illustrates that a gradual shift in meaning had taken place.
A related word was conscientia, which primarily means moral conscience. In the literal sense, “conscientia” means knowledge-with, that is, shared knowledge. The word first appears in Latin juridical texts by writers such as Cicero. Here, conscientia is the knowledge that a witness has of the deed of someone else. René Descartes (1596–1650) is generally taken to be the first philosopher to use “conscientia” in a way that does not fit this traditional meaning. Descartes used “conscientia” the way modern speakers would use “conscience.” In Search after Truth he says “conscience or internal testimony” (conscientia vel interno testimonio).
In philosophy
The philosophy of mind has given rise to many stances regarding consciousness. Any attempt to impose an organization on them is bound to be somewhat arbitrary There are, however, two approaches that are probably the most widely used. One is to follow a historical path by associating stances with the philosophers who are most most strongly associated with them, for example Descartes, Locke, Kant, etc. The approach followed in this section, though, is to organize philosophical stances according to the answers they give to a set of basic questions about the nature and status of consciousness.
Is consciousness a valid concept?
A majority of philosophers have felt that the word consciousness names a genuine entity, but some who belong to the physicalist and behaviorist schools have not been convinced. Many scientists have also been skeptical. The most compelling argument for the existence of consciousness is that the vast majority of mankind have an overwhelming intuition that there truly is such a thing. Skeptics argue that this intuition, in spite of its compelling quality, is false, either because the concept of consciousness is intrinsically incoherent, or because our intuitions about it are based in illusions. Gilbert Ryle, for example, argued that traditional understanding of consciousness depends on a Cartesian dualist outlook that improperly distinguishes between mind and body, or between mind and world. He proposed that we speak not of minds, bodies, and the world, but of individuals, or persons, acting in the world. Thus, by speaking of ‘consciousness,’ we end up misleading ourselves by thinking that there is any sort of thing as consciousness separated from behavioral and linguistic understandings.
Many philosophers and scientists have been unhappy about the difficulty of producing a definition that does not involve circularity or fuzziness. The neuroscientist Antonio Damasio, for example, calls consciousness “the feeling of what happens”, and defines it as “an organism’s awareness of its own self and its surroundings”. These formulations seem intuitively reasonable, but they are difficult to apply to specific situations.
Is it a single thing?
Many philosophers have argued that consciousness is a unitary concept that is understood intuitively by the majority of people in spite of the difficulty in defining it. Others, though, have argued that the level of disagreement about the meaning of the word indicates that it either means different things to different people, or else is an umbrella term encompassing a variety of distinct meanings with no simple element in common.
Ned Block proposed a distinction between two types of consciousness that he called phenomenal (P-consciousness) and access (A-consciousness). P-consciousness, according to Block, is simply raw experience: it is moving, colored forms, sounds, sensations, emotions and feelings with our bodies and responses at the center. These experiences, considered independently of any impact on behavior, are called qualia. A-consciousness, on the other hand, is the phenomenon whereby information in our minds is accessible for verbal report, reasoning, and the control of behavior. So, when we perceive, information about what we perceive is access conscious; when we introspect, information about our thoughts is access conscious; when we remember, information about the past is access conscious, and so on. Although some philosophers, such as Daniel Dennett, have disputed the validity of this distinction, others have broadly accepted it. David Chalmers has argued that A-consciousness can in principle be understood in mechanistic terms, but that understanding P-consciousness is much more challenging: he calls this the hard problem of consciousness. Dennett denies that the concept of qualia is coherent, that P-consciousness is intrinsically different from A-consciousness, and that there is anything especially hard about the “hard problem”.
Berit Brogaard has argued that even if there is a single concept of consciousness, it does not have determinate application conditions. So, there are cases in which it is neither the case that a state is conscious nor the case that it is not conscious.
How does it relate to the physical world?
Main article: Mind–body problem
Illustration of dualism by René Descartes. Inputs are passed by the sensory organs to the pineal gland and from there to the immaterial spirit.
The first influential philosopher to discuss this question specifically was Descartes, and the answer he proposed is known as Cartesian dualism. Descartes proposed that consciousness resides within an immaterial domain he called res cogitans (the realm of thought), in contrast to the domain of material things which he called res extensa (the realm of extension). He suggested that the interaction between these two domains occurs inside the brain, perhaps in a small midline structure called the pineal gland.
Although it is widely accepted that Descartes explained the problem cogently, few later philosophers have been happy with his solution, and his ideas about the pineal gland have especially been ridiculed. Alternative solutions, however, have been very diverse. They can be divided broadly into two categories: dualist solutions that maintain Descartes’s rigid distinction between the realm of consciousness and the realm of matter but give different answers for how the two realms relate to each other; and monist solutions that maintain that there is really only one realm of being, of which consciousness and matter are both aspects. Each of these categories itself contains numerous variants. The two main types of dualism are substance dualism (which holds that the mind is formed of a distinct type of substance not governed by the laws of physics) and property dualism (which holds that the laws of physics are universally valid but cannot be used to explain the mind). The three main types of monism are physicalism (which holds that the mind consists of matter organized in a particular way), idealism (which holds that only thought truly exists and matter is merely an illusion), and neutral monism (which holds that both mind and matter are aspects of a distinct essence that is itself identical to neither of them). There are also, however, a large number of idiosyncratic theories that cannot cleanly be assigned to any of these camps.
Since the dawn of Newtonian science with its vision of simple mechanical principles governing the entire universe, some philosophers have been tempted by the idea that consciousness could be explained in purely physical terms. The first influential writer to propose such an idea explicitly was Julien Offray de La Mettrie, in his book Man a Machine (L’homme machine).
The most influential modern physical theories of consciousness are based on psychology and neuroscience. Theories proposed by neuroscientists such as Gerald Edelman and António Damásio, and by philosophers such as Daniel Dennett, seek to explain access consciousness and phenomenal consciousness in terms of neural events occurring within the brain. Many other neuroscientists, such as Christof Koch, have explored the neural basis of consciousness without attempting to frame all-encompassing global theories. At the same time, computer scientists working in the field of Artificial Intelligence have pursued the goal of creating digital computer programs that can simulate or embody consciousness.
Several physicists have argued that classical physics is intrinsically incapable of explaining the holistic aspects of consciousness, but that quantum theory provides the missing ingredients. Several theorists have therefore proposed quantum mind (QM) theories of consciousness; the most notable theories falling into this category include the Holonomic brain theory of Karl H. Pribram and David Bohm, and the Orch-OR theory formulated by Stuart Hameroff and Roger Penrose. Some of these QM theories offer descriptions of phenomenal consciousness, as well as QM interpretations of access consciousness. None of the quantum mechanical theories has been confirmed by experiment, and many scientists and philosophers consider the arguments for an important role of quantum phenomena to be unconvincing.
Some theorists hold that phenomenal consciousness in particular creates an explanatory gap. Colin McGinn takes the New Mysterianism position that it can’t be solved, and David Chalmers criticizes purely physical accounts of mental experiences based on the idea that philosophical zombies are logically possible and supports property dualism.
How does it relate to language?
In humans, the clearest visible indication of consciousness is the ability to use language. Medical assessments of consciousness rely heavily on an ability to respond to questions and commands, and in scientific studies of consciousness, the usual criterion for awareness is verbal report (that is, subjects are deemed to be aware if they say that they are). Thus there is a strong connection between consciousness and language at a practical level. Philosophers differ, however, on whether language is essential to consciousness or merely the most powerful tool for assessing it.
Descartes believed that language and consciousness are bound tightly together. He thought that many of the behaviors humans share with other animals could be explained by physical processes such as reflexes, but that language could not be: he took the fact that animals lack language to be an indication that they lack access to res cogitans, the realm of thought. Others have reached similar conclusions, though sometimes for different reasons. Julian Jaynes argued in The Origin of Consciousness in the Breakdown of the Bicameral Mind that for consciousness to arise, language needs to have reached a fairly high level of complexity. Merlin Donald also argued for a critical dependence of consciousness on the ability to use symbols in a sophisticated way.
Those are, however, minority views. If language is essential, then speechless humans (infants, feral children, aphasics, etc.) could not be said to be conscious, a conclusion that the majority of philosophers have resisted. The implication that only humans, and not other animals, are conscious is also widely resisted by theorists such as evolutionary psychologists, as well as by animal rights activists.
Why do people believe that other people are conscious?
Many philosophers consider experience to be the essence of consciousness, and believe that experience can only fully be known from the inside, subjectively. But if consciousness is subjective and not visible from the outside, why do the vast majority of people believe that other people are conscious, but rocks and trees are not? This is the problem of other minds. It is particularly acute for people who believe in the possibility of philosophical zombies, that is, people who think it is possible in principle to have an entity that is physically indistinguishable from a human being and behaves like a human being in every way but nevertheless lacks consciousness.
The most commonly given answer is that we attribute consciousness to other people because we see that they resemble us in appearance and behavior: we reason that if they look like us and act like us, they must be like us in other ways, including having experiences of the sort that we do. There are, however, a variety of problems with that explanation. For one thing, it seems to violate the principle of parsimony, by postulating an invisible entity that is not necessary to explain what we observe. Some philosophers, such as Daniel Dennett in an essay titled The Unimaginable Preposterousness of Zombies, argue that people who give this explanation do not really understand what they are saying. More broadly, philosophers who do not accept the possibility of zombies generally believe that consciousness is reflected in behavior (including verbal behavior), and that we attribute consciousness on the basis of behavior. A more straightforward way of saying this is that we attribute experiences to people because they tell us about their experiences.
How can we know whether non-human animals are conscious?
Am I conscious?
The topic of animal consciousness is bedeviled by a number of difficulties. It poses the problem of other minds in an especially severe form, because animals, lacking language, cannot tell us about their experiences. Also, it is difficult to reason objectively about the question, because a denial that an animal is conscious is often taken as an assertion that its life has no value, and that harming it is not morally wrong. Descartes, for example, has sometimes been blamed for mistreatment of animals due to the fact that he believed only humans have a non-physical mind. Most people have a strong intuition that some animals, such as dogs, are conscious, while others, such as insects, are not; but the sources of this intuition are not obvious.
Philosophers who consider subjective experience the essence of consciousness also generally believe, as a correlate, that the existence and nature of animal consciousness caever rigorously be known. Thomas Nagel spelled out this point of view in an influential essay titled What Is it Like to Be a Bat? He said that an organism is conscious “if and only if there is something that it is like to be that organism — something it is like for the organism”; and he argued that no matter how much we know about an animal’s brain and behavior, we caever really put ourselves into the mind of the animal and experience its world in the way it does itself. More scientifically oriented philosophers such as Douglas Hofstadter dismiss this argument as essentially incoherent. Several psychologists and ethologists have argued for the existence of animal consciousness by describing a range of behaviors that appear to show animals holding beliefs about things they cannot directly perceive — Donald Griffin‘s 2001 book Animal Minds reviews a substantial portion of the evidence.
Could a machine ever be conscious?
“Teddy” from the film A.I. Artificial Intelligence. Could a robot like this ever be conscious?
The idea that consciousness is fundamentally mechanical can be traced back at least to
Though sometimes thought of as a test for consciousness, the Turing test, named after computer scientist Alan Turing who proposed it, was originally presented as an operational replacement for the question “Can machines think?”, which Turing regarded as too ambiguous to be meaningful.This test is commonly cited in discussion of artificial intelligence. The test is based on an “Imitation Game” in which a human experimenter converses, via computer keyboards, with two competitors, one human, the other a computer. Because all of the conversation is by keyboard, no cues such as voice, prosody, or appearance will be available to indicate which is human and which is the computer. If the human judge is unable to determine which of the conversants is the computer, the computer is said to have “passed” the test. The Turing test has generated a great deal of philosophical debate. For example, Daniel Dennett and Douglas Hofstadter argue that anything capable of passing the Turing test is necessarily conscious, while David Chalmers, argues that a philosophical zombie could pass the test, yet fail to be conscious.
Scientific approaches
For many decades, consciousness as a research topic was avoided by the majority of mainstream scientists, because of a general feeling that a phenomenon defined in subjective terms could not properly be studied using objective experimental methods. Starting in the 1980s, though, an expanding community of neuroscientists and psychologists have associated themselves with a field called Consciousness Studies, giving rise to a stream of experimental work published in journals such as Consciousness and Cognition, and methodological work published in journals such as the Journal of Consciousness Studies, along with regular conferences organized by groups such as the Association for the Scientific Study of Consciousness.
Modern scientific investigations into consciousness are based on psychological experiments (including, for example, the investigation of priming effects using subliminal stimuli), and on case studies of alterations in consciousness produced by trauma, illness, or drugs. Broadly viewed, scientific approaches are based on two core concepts. The first identifies the content of consciousness with the experiences that are reported by human subjects; the second makes use of the concept of consciousness that has been developed by neurologists and other medical professionals who deal with patients whose behavior is impaired. In either case, the ultimate goals are to develop techniques for assessing consciousness objectively in humans as well as other animals, and to understand the neural and psychological mechanisms that underlie it.
