Sunday, February 19, 2012


Consciousness of an unconscious person
Canadian-American cognitive scientist Steven Arthur Pinker wrote in the TIME Science Magazine of Jan. 29, 2007:  “The young women had survived the car crash, after a fashion. In the five months since parts of her brain had been crushed, she could open her eyes but didn't respond to sights, sounds or jabs. In the jargon of neurology, she was judged to be in a persistent vegetative state. In crueler everyday language, she was a vegetable.
“So picture the astonishment of British and Belgian scientists as they scanned her brain using a kind of MRI that detects blood flow to active parts of the brain. When they recited sentences, the parts involved in language lit up. When they asked her to imagine visiting the rooms of her house, the parts involved in navigating space and recognizing places ramped up. And when they asked her to imagine playing tennis, the regions that trigger motion joined in. Indeed, her scans were barely different from those of healthy volunteers. The woman, it appears, had glimmerings of consciousness…”
Two problems
Questions once confined to speculations of spiritualists and theologians are now at the forefront of cognitive neuroscience. There are two questions on the problem of consciousness in cognitive science. The philosopher David Chalmers has categorized them into two: Easy Problem and the Hard Problem.
The easy problem
The Easy Problem is to distinguish conscious from unconscious mental functions, identify its correlates in the brain and explain why it evolved. Thanks to Freudian psychoanalytic theory the term unconscious became famous a century ago. But the Freudian ‘unconscious mind’ has nothing to do with the cognitive processes occurring without conscious awareness of the individual. Freudian theories are hermeneutical. Hermeneutics rests on interpretations only.
Some cognitive processes occurring in the brain such as daydreams, plans for the day, solving the problems, pleasures and peeves, etc. are conscious. You can ponder them, discuss them and let them guide your behavior. Other processes like applying the rules that order the words as you speak and the sequence of muscle contractions that allow you to drive a car or hold a pen are unconscious. They must be in the brain somewhere because you couldn't walk and talk and see without them, but they are sealed off from your planning and reasoning circuits, and you can't say a thing about them.
Hard problem
The second problem is explaining how subjective experiences, such as “feeling green” when one sees green colour, arise from the neural processes in the brain. When one sees a green thing, not only does it look different from a red thing, remind him/her of other green things and prompt to say, "That's green", but it also actually looks green: it produces an “experience” or “feeling” of sheer greenness that isn't reducible to anything else. American jazz trumpeter and singer Louis Armstrong once said in response to a request to define jazz: "When you got to ask what it is, you never get to know." The problem is hard because no one knows what a solution might look like or even whether it is a genuine scientific problem in the first place. And not surprisingly, everyone agrees that the hard problem remains a mystery.
The Astonishing Hypothesis
The Astonishing Hypothesis is a 1994 book by scientist Francis Crick about consciousness. Crick is one of the co-discoverers of the molecular structure of DNA in 1953. Later he became a theorist for neurobiology and the study of the brain. The Astonishing Hypothesis is mostly concerned with establishing a basis for scientific study of consciousness. Crick places the study of consciousness within a larger social context. Human consciousness is central to human existence and so scientists find themselves approaching topics traditionally left to philosophy and religion.
The Astonishing Hypothesis posits that "a person's mental activities are entirely due to the behavior of the cells of the brain and the atoms, ions, and molecules that make them up and influence them. Crick claims that scientific study of the brain during the 20th century lead to acceptance of consciousness, free will, and the human soul as subjects for scientific investigation.
Crick had discussed the relationship between science and religion in his earlier book What Mad Pursuit. Crick's view of this relationship was that religions can be wrong about scientific matters and that part of what science does is to confront the errors that exist within religious traditions. For example, the idea of a mechanism for the evolution of life by natural selection conflicts with some views on creation of life by divine intervention. Crick's subtitle for The Astonishing Hypothesis is The Scientific Search for the Soul. Crick argued that traditional conceptualizations of the soul as a non-material being must be replaced by a materialistic understanding of how the brain produces mind.
In his review of Crick's book, J. J. Hopfield (Science magazine, 4 February 1994) concluded that, “The book should be read by scientists for its eloquent attempt to put consciousness, which we so much equate with the essence of our humanity, into the realm of science.”
Crick's ‘astonishing’ hypothesis is: "You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules."
The brain as machine
Scientists have exorcised the ghost from the machine not because they are mechanistic killjoys who spoil the enthusiasm or fun of others, but because they have amassed evidence that every aspect of consciousness can be tied to the brain. Using functional MRI scan, cognitive neuroscientists can almost read people's thoughts from the blood flow in their brains. They can tell, for instance, whether a person is thinking about a face or a place or whether a picture the person is looking at is of a bottle or a shoe. And consciousness can be pushed around by physical manipulations. Electrical stimulation of the brain during surgery can cause a person to have false visions and hearings (hallucinations) that are indistinguishable from reality. Chemicals that affect the brain can profoundly alter how people think, feel and see. Examples are intoxicants like cocaine, alcohol etc. and drugs like chlorpromazine, diazepam etc. Surgery that severs the corpus callosum, separating the two hemispheres (a treatment for epilepsy), spawns two consciousnesses within the same skull, as if the soul could be cleaved in two with a knife.
Story of the murderous left hand
More than fifty years ago a middle aged woman came to the world renowned neurologist Kurt Goldstein.The lady appeared normal in all respects of behaviour and communication. But she had a strange complaint—every now and then her left hand would come unto her throat and try to strangle her. She often had to restrain forcefully the murderous left hand with her right one. Her primary physician suspected some mental disorder and referred to her many psychiatrists, but none of them could find any mental abnormality with her. A detailed examination by Dr. Goldstein established that she was neurologically and mentally normal. But Dr. Goldstein came up with an explanation for her or rather her left hand’s bizarre behaviour. Each of the two hemispheres of brain is specialized for different mental capacities. The right hemisphere controls the muscles of the left side and vice versa. The two hemispheres are connected with thick band of fibers called corpus callosum that allows the two sides to communicate and stay in sync. This woman’s right hemisphere, which controls the movements of left hand, seemed to have some latent suicidal tendencies—a genuine urge to kill herself. Initially these urges may have been held in check by the inhibitory messages sent across the corpus callosum from the more rational left hemisphere. But if she had suffered, as Goldstein surmised, damage to the corpus callosum as the result of a silent stroke, that inhibition would be removed. The suicidal right side of her brain and the murderous left hand were now free to attempt to strangle her. The neuroscientist VS Rmachandran commented on Dr. Goldstein’s explanation: “This explanation is not as far-fetched as it seems, since it’s has been well known for some time that the right hemisphere tends to be more emotionally volatile than the left. Patients who have a stroke in the left brain are often anxious, depressed or worried about their prospects for recovery. The reason seems to be that with the left brain injured; their right brain takes over and frets about everything. In contrast, people who suffer damage to the right hemisphere tend to be blissfully indifferent to their predicament. The left hemisphere just doesn’t get all that upset.” (PHANTOMS IN THE BRAIN p.12)
Brain circuitry is the basis of intact consciousness
Let us consider a peculiar disorder in which a person holds adelusion, an incorrigible false belief, that spouse, parent, or other close family member has been replaced by an identical-looking impostor. This disorder is called Capgras delusion. It is named after Joseph Capgras (1873–1950), a French psychiatrist who first described the disorder in 1923 on the case of a French woman who complained that corresponding "doubles" had taken the places of her husband and other people she knew.
Some of the first clues to the possible causes of the Capgras delusion were suggested by the study of brain-injured patients who had developed prosopagnosia in which patients are unable to recognize faces consciously, despite being able to recognize other types of visual objects. In 1997, William Hirstein and Vilayanur S. Ramachandran reported similar findings in a paper published on a single case of a patient with Capgras delusion after brain injury.  Ramachandran also portrayed this case in his book Phantoms in the Brain. Since the patient was capable of feeling emotions and recognizing faces but could not feel emotions when recognizing familiar faces, Ramachandran hypothesizes that the origin of Capgras syndrome is a disconnection between the temporal cortex, where faces are usually recognized and the limbic system, involved in emotions.
Consciousness exists when brain is alive
When the physiological activity of the brain ceases, as far as anyone can tell the person's consciousness goes out of existence. Attempts to contact the souls of the dead (a pursuit of serious scientists a century ago) turned up only cheap magic tricks, and near death experiences are not the eyewitness reports of a soul parting company from the body but symptoms of oxygen starvation experienced by brain and reflected on to the weakened consciousness.
Tackling the hard problem
Daniel Dennet
To appreciate the hardness of the hard problem, consider how you could ever know whether you see colors the same way that I do. Sure, you and I both call grass green, but perhaps you see grass as having the color that I would describe, if I were in your shoes, as purple. Or ponder whether there could be a true zombie—a being who acts just like you or me but in whom there is no self actually feeling anything.
No one knows what to do with the Hard Problem. Some people may see it as an opening to sneak the soul back in, but this just re-labels the mystery of "consciousness" as the mystery of "the soul"—a word game that provides no insight.
Many philosophers, like Daniel Dennett, deny that the Hard Problem exists at all. 

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