The word "consciousness" is derived from Latin conscientia which primarily means moral conscience. In the literal sense, "conscientia" (or "con scientia") means knowledge-with, that is, shared knowledge. The word first appears in Latin juridic texts by writers such as Cicero. Here, conscientia is the knowledge that a witness has of the deed of someone else. In Christian theology, conscience stands for the moral conscience in which our actions and intentions are registered and which is only fully known to God. Medieval writers such as Thomas Aquinas describe the conscientia as the act by which we apply practical and moral knowledge to our own actions.[7] René Descartes has been said to be the first philosopher to use "conscientia" in a way that does not seem to fit this traditional meaning, and, as a consequence, the translators of his writings in other languages like French and English coined new words in order to denote merely psychological consciousness. These are, for instance, conscience, and Bewusstsein.[8] However, it has also been argued that John Locke was in fact the first one to use the modern meaning of consciousness in his Essay Concerning Human Understanding, although it remains closely intertwined with moral conscience (I may be held morally responsible only for the act of which I am conscious of having achieved; and my personal identity - my self - goes as far as my consciousness extends itself). However, it is the case that Ralph Cudworth was in fact the first one to use the modern meaning of consciousness in his "True Intellectual System of the Universe" (1678). It too remains closely intertwined with moral agency, but does not in itself signify conscience. The modern sense of consciousness was therefore first found not in Descartes' work - who sometimes used the word in a modern sense, but did not distinguish it as much as Locke would do - nor in Locke's text, but Cudworth's. The contemporary sense of the word consciousness (consciousness associated with the idea of personal identity, which is assured by the repeated consciousness of oneself) was introduced by Cudworth. The word "conscience" was coined by Pierre Costes, French translator of Locke, but in the English language the modern sense first appeared in Cudworth's works.[9] It is true, however, that Locke much influenced the subsequent reception of consciousness: in Samuel Johnson's celebrated Dictionary, Johnson gives a definition of "conscious" as "endowed with the power of knowing one's own thoughts and actions," and takes Locke's own definition of "consciousness" as "the perception of what passes in a man's own mind." in particle physics,consciousness can be defined in terms of wave. one feels conscious when the waves from the source or the nature superimposes the wave he has in his mind. when they impose, they create a new wave model that explains the consciousness of an individual.
Phenomenal and access consciousness
Phenomenal consciousness (P-consciousness) is simply experience; it is moving, coloured 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. The hard problem of consciousness was formulated by Chalmers in 1996, dealing with the issue of "how to explain a state of phenomenal consciousness in terms of its neurological basis" (Block 2004).
Access consciousness (A-consciousness) 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 often access conscious; when we introspect, information about our thoughts is access conscious; when we remember, information about the past (e.g., something that we learned) is often access conscious; and so on. Chalmers thinks that access consciousness is less mysterious than phenomenal consciousness, so that it is held to pose one of the easy problems of consciousness. Dennett denies that there is a "hard problem", asserting that the totality of consciousness can be understood in terms of impact on behavior, as studied through heterophenomenology. There have been numerous approaches to the processes that act on conscious experience from instant to instant. Dennett (1988) suggests that what people think of as phenomenal consciousness, such as qualia, are judgments and consequent behaviour. He extends this analysis (Dennett, 1996) by arguing that phenomenal consciousness can be explained in terms of access consciousness, denying the existence of qualia, hence denying the existence of a "hard problem." Chalmers, on the other hand, argues that Dennett's explanatory processes merely address aspects of the easy problem. Eccles and others have pointed out the difficulty of explaining the evolution of qualia, or of 'minds' which experience them, given that all the processes governing evolution are physical and so have no direct access to them. There is no guarantee that all people have minds, nor any way to verify whether one does or does not possess one.
Events that occur in the mind or brain that are not within phenomenal or access consciousness are known as subconscious events.
The description and location of phenomenal consciousness
For centuries, philosophers have investigated phenomenal consciousness. René Descartes, who arrived at the famous dictum 'cogito ergo sum', wrote Meditations on First Philosophy in the seventeenth century. He described, extensively, what it is to be conscious. Conscious experience, according to Descartes, included such ideas as imaginings and perceptions laid out in space and time that are viewed from a point, and appearing as a result of some quality (qualia) such as color, smell, and so on. (Modern readers are often confused by this Descartes' notion of interchangeability between the terms 'idea' and 'imaginings.')
Like Aristotle, Descartes defines ideas as extended things, as in this excerpt from his Treatise on Man:
Now among these figures, it is not those imprinted on the external sense organs, or on the internal surface of the brain, which should be taken to be ideas - but only those which are traced in the spirits on the surface of gland H [where the seat of the imagination and the 'common sense' is located]. That is to say, it is only the latter figures which should be taken to be the forms or images which the rational soul united to this machine will consider directly when it imagines some object or perceives it by the senses.
Thus Descartes does not identify mental ideas or 'qualia' with activity within the sense organs, or even with brain activity, but rather with interaction between body and the 'rational soul', through the mediating 'gland H'. This organ is now known as the pineal gland. Descartes notes that, anatomically, while the human brain consists of two symmetrical hemispheres the pineal gland, which lies close to the brain's centre, is singular. Thus he extrapolated from this that it was the mediator between body and soul.
Other philosophers agreed with Descartes to varying degrees. They include Nicolas Malebranche, Thomas Reid, John Locke, David Hume and Immanuel Kant. Malebranche, for example, agreed with Descartes that the human being was composed of two elements, body and mind, and that conscious experience resided in the latter. He did, however, disagree with Descartes as to the ease with which we might become aware of our mental constitution, stating 'I am not my own light unto myself'. David Hume and Immanuel Kant also differ from Descartes, in that they avoid mentioning a place from which experience is viewed (see "Further reading" below); certainly, few if any modern philosophers have identified the pineal gland as the seat of dualist interaction.
The extension of things in time was considered in more detail by Kant and James. Kant wrote that "only on the presupposition of time can we represent to ourselves a number of things as existing at one and the same time [simultaneously] or at different times [successively]." William James stressed the extension of experience in time and said that time is "the short duration of which we are immediately and incessantly sensible."
When we look around a room or have a dream, things are laid out in space and time and viewed as if from a point. However, when philosophers and scientists consider the location of the form and contents of this phenomenal consciousness, there are fierce disagreements. As an example, Descartes proposed that the contents are brain activity seen by a non-physical place without extension (the Res Cogitans), which, in Meditations on First Philosophy, he identified as the soul. This idea is known as Cartesian Dualism. Another example is found in the work of Thomas Reid who thought the contents of consciousness are the world itself, which becomes conscious experience in some way. This concept is a type of Direct realism. The precise physical substrate of conscious experience in the world, such as photons, quantum fields, etc. is usually not specified.
Other philosophers, such as George Berkeley, have proposed that the contents of consciousness are an aspect of minds and do not necessarily involve matter at all. This is a type of Idealism. Yet others, such as Leibniz, have considered that each point in the universe is endowed with conscious content. This is a form of Panpsychism. Panpsychism is the belief that all matter, including rocks for example, is sentient or conscious. The concept of the things in conscious experience being impressions in the brain is a type of representationalism, and representationalism is a form of indirect realism.
It is sometimes held that consciousness emerges from the complexity of brain processing. The general label 'emergence' applies to new phenomena that emerge from a physical basis without the connection between the two explicitly specified.
Physicalists claim that consciousness must arise from the neuronal interactions in the brain, a hugely complicated machine with about 10 million million neurones, each with thousands of excitatory and inhibitory connections “votes,” with no mystery stuff. These neuronal interactions must use voting mechanisms to deliver outcomes. But voting systems can produce different results from the same voter base and such voting result variations provide the required indeterminacy which provides freedom from rigid deterministic mechanisms (Welsby PD. Problems with voting: the ultimate source? Int Journal of Design & Nature Vol2, No 4, 2007). Sufficiently complex brains will have a coordinating system which, when confronted by such indeterminacy, will become aware that it has been burdened with free will as it has to determine which of the voting systems will be chosen to get the result. This, according to the theory, is the origin of free will; awareness of free will in turn leads to self-awareness, and self-awareness is consciousness.
Investigators have failed to agree on an anatomical mechanism for consciousness. To those who support the emergence theory, this is predictable because consciousness is not an anatomical feature but a function; one that that emerges from billions of neurones and their voting interactions, in the way that a rainbow emerges from billions of raindrops.
Some theorists hold that phenomenal consciousness poses an explanatory gap. Colin McGinn takes the New Mysterianism position that it can't be solved, and Chalmers criticizes purely physical accounts of mental experiences based on the idea that philosophical zombies are logically possible and supports property dualism. But others have proposed speculative scientific theories to explain the explanatory gap, such as Quantum mind, space-time theories of consciousness, reflexive monism, and Electromagnetic theories of consciousness to explain the correspondence between brain activity and experience.
Parapsychologists sometimes appeal to the unproven concepts of psychokinesis or telepathy to support the belief that consciousness is not confined to the brain.
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