Consciousness
The word conscious first appeared in English during the 17th century as a simple adjective applied to inanimate objects. A 1643 text described "the conscious Groves" using the term figuratively for nature itself. This usage derived from the Latin root conscius, which combined con meaning together and scio meaning to know. The original phrase meant knowing with another person or sharing joint knowledge about a secret fact. Thomas Hobbes wrote in his 1651 book Leviathan that two men who know of one and the same fact are said to be conscious of it one to another. The Latin phrase conscius sibi translated literally as knowing with oneself or sharing knowledge with oneself about something. Archbishop Ussher used this phrasing in 1613 when he wrote of being so conscious unto himself of his great weakness. The Roman juridical texts by Cicero introduced conscientia as a kind of shared knowledge with moral value regarding what a witness knows of someone else's deeds. René Descartes began writing in Latin around 1600 and is generally taken to be the first philosopher to use conscientia in a way less like the traditional meaning. He provided a gloss in Search after Truth published in Amsterdam in 1701 stating conscientiâ vel interno testimonio. This phrase translates as conscience or internal testimony and might mean the knowledge of the value of one's own thoughts. John Milton's poetry played a role in shifting the word from conscience to consciousness during the seventeenth century. John Locke defined the modern concept in his Essay Concerning Human Understanding published in 1690 as the perception of what passes in a man's own mind. Samuel Johnson included Locke's definition in his celebrated Dictionary released in 1755. The French term conscience appeared roughly like English consciousness in the 1753 volume of Diderot and d'Alembert's Encyclopédie.
Modern dictionary definitions evolved over several centuries reflecting a range of seemingly related meanings that have been controversial. Webster's Third New International Dictionary published in 1966 listed awareness or perception of an inward psychological fact alongside intuitively perceived knowledge of something in one's inner self. The Cambridge English Dictionary defines consciousness as the state of being awake thinking and knowing what is happening around you. The Oxford Living Dictionary describes it as the state of being aware of and responsive to one's surroundings. Philosophers have used technical jargon to clarify distinctions between phenomenal experience and access to information. Ned Block argued that discussions often fail to distinguish phenomenal consciousness from access consciousness. P-consciousness refers to raw experience including moving colored forms sounds sensations emotions and feelings with our bodies at the center. A-consciousness describes the phenomenon whereby information in minds is accessible for verbal report reasoning and control of behavior. Daniel Dennett disputed the validity of this distinction while David Chalmers called understanding P-consciousness the hard problem of consciousness. William Lycan identified at least eight clearly distinct types of consciousness in his book Consciousness and Experience published later. Thomas Nagel used phrases like subjective character of experience to refer to something occurring at many levels of animal life. Peter Hacker attacked Nagel's terminology in 2002 calling it malformed and meaningless English. He asserted in 2012 that Nagel had laid the groundwork for forty years of fresh confusion about consciousness. Max Velmans proposed that everyday understanding refers to experience itself rather than any particular thing observed or experienced. Julian Jaynes insisted in 1976 that without introspection there could be no conception of what consciousness is. He reaffirmed this traditional idea in 1990 writing that its denotative definition matches René Descartes John Locke and David Hume.
A major part of scientific literature examines the relationship between experiences reported by subjects and activity simultaneously taking place in their brains. Several brain imaging techniques such as EEG and fMRI have been used for physical measures of brain activity in these studies. An idea drawing attention for several decades suggests consciousness is associated with high-frequency gamma band oscillations in brain activity. Christof von der Malsburg and Wolf Singer proposed in the 1980s that gamma oscillations could solve the binding problem by linking information represented in different parts of the brain into a unified experience. Rodolfo Llinás proposed that consciousness results from recurrent thalamo-cortical resonance where specific systems interact via synchronous oscillations. Activity in primary sensory areas like the visual cortex V1 is not sufficient to produce consciousness according to multiple studies. Subjects can report lack of awareness even when areas such as V1 show clear electrical responses to a stimulus. Higher brain areas including the prefrontal cortex are seen as more promising candidates for generating conscious awareness. Studies by Nikos Logothetis showed visually responsive neurons in temporal lobe reflect perception during binocular rivalry. Top-down feedback from higher to lower visual brain areas may be weaker or absent in peripheral fields yet humans perceive inputs there. Changes in firing rates and synchrony correlate with phenomenal experience of stimulus intensity in primary visual areas. The perturbational complexity index PCI was proposed in 2013 as a measure of algorithmic complexity of electrophysiological response to transcranial magnetic stimulation. This measure proved higher in awake individuals REM sleepers and locked-in patients than those in deep sleep or vegetative states. A study in 2016 looked at lesions in specific brainstem regions associated with coma and vegetative states. Researchers identified a small region called rostral dorsolateral pontine tegmentum driving consciousness through functional connectivity with cortical regions. Krista and Tatiana Hogan twins possess unique thalamic connections that may provide insight into how experiences could be shared between brains.
A wide range of empirical theories have been proposed to explain the nature of consciousness across different frameworks. Global workspace theory GWT emerged as a cognitive architecture proposed by Bernard Baars in 1988 using theater metaphors. Baars described conscious processes represented by an illuminated stage integrating inputs from unconscious networks broadcasting them to unlit audiences. Stanislas Dehaene and Lionel Naccache expanded upon this model over subsequent decades. Integrated information theory IIT pioneered by Giulio Tononi in 2004 postulates consciousness resides in processed information reaching certain complexity levels. Proponents suggest it provides physical grounding for consciousness in neurons offering mechanisms by which information integrates. In 2023, 124 scholars signed a letter claiming IIT receives disproportionate media attention relative to supporting evidence calling it pseudoscience. Orchestrated objective reduction Orch-OR proposes consciousness originates at quantum level inside neurons via microtubules forming cytoskeletons around brain structures. Roger Penrose published his views in The Emperor's New Mind while Stuart Hameroff developed the mechanism further. Quantum vibrations discovered inside microtubules in 2014 gave new life to arguments despite criticism regarding Gödel theorem interpretations. Attention schema theory introduced by Michael Graziano and Kastner in 2011 suggests specific cortical areas build constructs of awareness attributed to others or oneself. Damage to superior temporal sulcus or temporo-parietal junction leads to deficits like hemispatial neglect. Entropic brain theory informed by neuroimaging with psychedelic drugs suggests primary states such as REM sleep form disordered states normal waking consciousness constrains freedom. Projective consciousness model PCM applied active inference paradigm in 2017 integrating sensory data with priors through projective transformation. Francis Crick proposed claustrum acts as conductor binding individual experience together though he died before completing work on idea. A study induced unconsciousness in 54-year-old woman suffering from epilepsy by stimulating her claustrum confirming its role in network subserving consciousness.
The emergence of consciousness during biological evolution remains topic of ongoing scientific inquiry into survival value across species. Thomas Henry Huxley defended epiphenomenalist theory claiming consciousness is causally inert effect of neural activity like steam-whistle accompanying locomotive engine machinery. William James objected stating evolutionary argument implies preservation development resulted from natural selection giving consciousness survival value itself. Karl Popper developed similar evolutionary arguments in The Self and Its Brain discussing mind-brain interaction implications. Opinions divide regarding when consciousness first arose including exclusively humans mammals birds reptiles or early vertebrates Cambrian period over 500 million years ago. Donald Griffin suggested gradual evolution of consciousness in his book Animal Minds while Peter Godfrey Smith explored origins particularly molluscs in Metazoa. Gerald Edelman described dynamic core hypothesis emphasizing reentrant connections reciprocating linking brain areas massively parallel manner. Primary consciousness shared by humans non-human animals contrasts with higher-order consciousness appearing uniquely in humans alongside language capacity. John Eccles argued special anatomical physical properties mammalian cerebral cortex gave rise to consciousness linked through quantum physics. Bernard Baars proposed recursive circuitry provided basis for subsequent functions facilitating higher organisms. Peter Carruthers suggested adaptive advantage allowing distinctions between appearance reality enabling creatures recognize perceptions deceiving them behave accordingly. Consciousness allows manipulation others recognizing how things appear cooperative devious ends yet no causal explanation exists why functionally equivalent non-conscious organism cannot achieve same advantages. Pinker Chomsky Edelman Luria indicated importance emergence human language as regulative mechanism learning memory context developing higher-order consciousness. Mirror test developed by Gordon Gallup in 1970s examines whether animals differentiate seeing themselves versus other animals. Humans older than 18 months great apes bottlenose dolphins orcas pigeons European magpies elephants observed passing this test. Pigs shown finding food looking into mirror indicating contingency awareness factor self-recognition relying intact medial temporal lobe age.
Some brain states exist where consciousness seems absent including dreamless sleep coma while various circumstances change relationship mind world less drastically producing altered states. Altered states occur naturally produced by drugs brain damage accompanied changes thinking disturbances sense time feelings loss control emotional expression body image meaning significance. Two most widely accepted altered states remain sleep and dreaming though each associated distinct pattern brain activity metabolic activity eye movement experience cognition. Ordinary non-dream sleep people awakened report vague sketchy thoughts experiences not cohering continuous narrative. Dream sleep contrast people awakened report rich detailed events forming continuous progression possibly interrupted bizarre fantastic intrusions. Thought processes during dream state frequently show high level irrationality both states associated severe disruption memory disappearing seconds minutes after awakening unless actively maintained. Medical definition uses level of consciousness terminology describing patient arousal responsiveness continuum ranging full alertness comprehension disorientation delirium loss meaningful communication finally loss movement response painful stimuli. Glasgow Coma Scale measures degree level consciousness through standardized behavior observation scales assessing severely ill comatose anesthetized people conditions impaired disrupted. Verbal report considered gold standard ascribing consciousness but restricts field study humans language pre-linguistic children types brain damage impairing language. Daniel Dennett argued heterophenomenology treating verbal reports stories may true ideas adopted widely not yet. Mirror test contingency awareness approaches apply specifically studying self-awareness ability distinguish oneself others recognizing conscious understanding actions effects environment. Brain processes during contingency awareness learning believed rely intact medial temporal lobe age supporting parietal cortex substrate awareness age-related disruption region sufficient impair awareness.
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Common questions
When did the word conscious first appear in English?
The word conscious first appeared in English during the 17th century as a simple adjective applied to inanimate objects. A text from 1643 described conscious Groves using the term figuratively for nature itself.
Who defined modern consciousness in his Essay Concerning Human Understanding published in 1690?
John Locke defined the modern concept of consciousness in his Essay Concerning Human Understanding published in 1690 as the perception of what passes in a man's own mind. Samuel Johnson included this definition in his celebrated Dictionary released in 1755.
What is the hard problem of consciousness according to David Chalmers?
David Chalmers called understanding P-consciousness the hard problem of consciousness. P-consciousness refers to raw experience including moving colored forms sounds sensations emotions and feelings with our bodies at the center.
Which brain region drives consciousness through functional connectivity with cortical regions identified in 2016?
Researchers identified a small region called rostral dorsolateral pontine tegmentum driving consciousness through functional connectivity with cortical regions in a study conducted in 2016. This region was associated with lesions found in specific brainstem areas linked to coma and vegetative states.
When did Global workspace theory emerge as a cognitive architecture proposed by Bernard Baars?
Global workspace theory emerged as a cognitive architecture proposed by Bernard Baars in 1988 using theater metaphors. Baars described conscious processes represented by an illuminated stage integrating inputs from unconscious networks broadcasting them to unlit audiences.