Timeline of Conscious Experience Theories
Our Conscious experiences are proof of the existence of a spiritual/divine realm because this phenomena is not a part of the material realm. Yet its evolutionary purpose remains a mystery. Consciousness only seems to exist in social animals at a level proportional to their pre-frontal cortex. This cortical region is responsible for route planning and reasoning by directing the flow of neural signals in the brain. It enhances some signals and suppresses others.
Descartes - Conscious Soul Connects to the Brain via Pineal Gland (1640)
(July 6, 2022) French philosopher Descartes (1596-1650) proposed that a conscious soul interacted with the material brain via the single pineal gland located at the bottom center of the brain. The soul, via the pineal gland, was responsible for all voluntary actions leaving the brain responsible for involuntary actions. He thought nerves were like hydraulic tubes being filled with a type of fluid called “animal spirits” which inflated the muscles upon the command of either the soul or the material brain (Risse 1973)
By 1800, electricity had replaced animal spirits. This came after the public cadaver demonstrations by Giovanni Aldini who popularized the pioneering electrical discoveries of Luigi Galvani and Alessandro Volta. In 1803 he electrified various muscles of a just killed murderer at the Royal College of Surgeons in London. In that demonstration various muscles were animated including eyelids. These sorts of demonstrations seem to have been the inspiration for Frankenstein written by Mary Shelley and published in London in 1818 (Ashcroft 2012).
This discovery that electricity caused animal movements caused a shift in viewpoint about the animating spirit. The brain came to be viewed as a complex mechanical automaton responsible for both voluntary and involuntary actions. Conscious experiences were even further marginalized because they seemed to have no purpose.
ReferencesAshcroft, Francis (2012) The Spark of Life. W.W. Norton & Company, New York, London
Risse, Guenter B. (1973) The History of Physiology. Robert Krieger Publishing Co. Huntington, NY
TMS works by placing an electromagnet coil or coils on the scalp which is then pulsed at various frequencies. The magnetic field strength is about the same as that used in magnetic resonance imaging so they are much stronger than radio waves, and even with that power TMS only penetrates about 1.5 cm into the brain (Pascual-Leone and all 2002).
Anthony Barker and his colleagues in Britain showed that these strong magnetic pulses could replace direct electrical stimulation of the brain in generating electric neural action potentials (Barker and all 1985). They then used this technique this to determine how various motor cortex regions map to spinal cord neurons. When applied to the primary visual cortex at the back of the head TMS patients usually report flashes of lights.
Henry Huxley Proposed Consciousness was an Epiphenomena (1884)
(July 6, 2022) This lack of a functional purpose for conscious experiences was and is a problem for the theory of evolution. This led Thomas Henry Huxley who was an early defender of evolution to propose in 1874 that conscious experiences were just an epiphenomena, a byproduct of mental activity in the same way that the sound of a heartbeat is a byproduct of the heart’s pumping action. In his speech he also argued that advanced traits such as consciousness must start out more simply in simpler animals which is certainly true. He said this about conscious experiences in his 1874 speech:The consciousness of brutes would appear to be related to the mechanism of their body simply as a collateral product of its working, and to be completely without any power of modifying that working as the steam-whistle which accompanies the work of a locomotive engine is without influence upon its machinery.
... the argumentation which applies to brutes holds equally good of men; and, therefore, that all states of consciousness in us, as in them, are immediately caused by molecular changes of the brain-substance. It seems to me that in men, as in brutes, there is no proof that any state of consciousness is the cause of change in the motion of the matter of the organism. If these positions are well based, it follows that our mental conditions are simply the symbols in consciousness of the changes which takes place automatically in the organism; and that, to take an extreme illustration, the feeling we call volition is not the cause of a voluntary act, but the symbol of that state of the brain which is the immediate cause of that act (Huxley 1874)
Huxley's collateral effect idea is wrong because he is assuming conscious experiences are a form of material energy. Conscious experiences are not found in any theory of modern physics. Additionally, they are produced in low energy brains when all the frontiers of physics are at high energies.
Because Huxley is assuming consciousness is energy based he is invoking the the concept of entropy which is the tendency of energy to spread out during any sort of energy usage.
ReferencesBarker,A.T. ; Jalinous, R. ;Freeston, I.L. (1985). "Non-Invasive Magnetic Stimulation of Human Motor Cortex". The Lancet 325 (8437): 1106–1107. doi:10.1016/S0140-6736(85)92413-4
Huxley, Thomas H (1874) On the Hypothesis that Animals Are Automata, and Its History. Found online at: http://aleph0.clarku.edu/huxley/CE1/AnAuto.html Pascual-Leone, A.; Davey, N.; Rothwell, J.; Wassermann, E.M.; Puri, B.K. (2002). Handbook of Transcranial Magnetic Stimulation. Arnold, London
Conscious Impressions as an Emergent Phenomena (1960s on)
(July 6, 2022) A recent popular updating of the epiphenomena idea is that conscious experiences are emergent in some way. Emergence is a precise mathematical term which describes how patterns are created out of simpler, lower level activities. The most glaring deficiency of this hypothesis for consciousness is that it cannot explain the variety of conscious experiences and their localizations in the brain.
The other deficiency of the emergent hypothesis is that no one has ever been able identify to which emergent class fits conscious experiences. Emergence comes in three types:
The first type of emergence is "transformation emergence" in which something emerges from another by some sort of mathematical transformation like scale, rotation, mirror images, motion rules, etc.
A second type of emergence is "cancellation emergence." This is a form of mathematical equation abstraction which cancels energy terms. Energy is still there but it is measured relative to something else. One such emergent concept is the idea of hardness which comes from the energy binding strength between molecules. Hardness is measured by a scratch test. Energy is there but it is hidden by the process of comparing one material to another. Another form energy cancellation emergence is the is the emergence of Snell’s law of refraction from quantum electrodynamics because it is the only pathway of light that is not cancelled out by interacting light waves.
A third form of emergence is "mapping emergence. which is based upon arbitrary mapping rules (figure 4). An example of this sort of emergence is the emergence of numeric computer programming machine code (numbers 1 and 0) from their voltage assignments. Higher level programming code in turn can emerge from these binary numbers when they are in turn mapped to decimal based numbers and word commands.
Psychon Theory by Neuroscientist John Eccles (1989)
(July 6, 2022) In 1989 retired Nobel Prize winning neuroscientist, John Eccles, proposed the first spirit realm theory of consciousness in nearly 2000 years. For the first time, a plausible mechanism for the spirit-nature connection was proposed. It consisted of a material world transceiver as some single neural protein while its corresponding transceiver in the non-material spiritual realm was called the psychon. John Eccles called the spiritual realm “World 2.” The problem was that his theory was not testable and it had many other flaws. (Eccles, 1989, p 191)
John Eccles was a Nobel prize winning neurologist who won his Nobel prize in 1963 for experiments performed during the early 1950’s proving that the signal across neural synapses was chemical instead of electrical. This discovery was key to establishing the then new science of neuroscience.
He proposed that signals from the psychons would increase the probability of vesicles merging into the membrane of the transmitting neuron. Likewise, the psychons were signaled when such attachments were made.
Eccles does not seem to have realized this caused an unworkable positive feedback loop. The more neurotransmitter released, the greater the conscious experience yet the greater the conscious experience, the more neurotransmitter would be released.
He also did not specify how this model produced the different types of conscious experiences (qualia) beyond stating that different qualia were the result activity in different cortical neurons. Still it was a bold proposal which could have only been made by a researcher at the end of an illustrious career. Only with the Variable Physical Constant Theory were this problems overcome.
ReferencesEccles, John (1989) Evolution of the Brain: Creation of the Self. Routledge; Revised ed. edition (May 18, 1991)
Conscious Experiences Needed to Overcome Some Limitation in the Brain's Information Processing (2004)
(July 6, 2022) Another popular class of proposals for conscious experiences revolves around the idea that they exist due to some limitation in the information processing ability by the brain. These theories implicitly assume that conscious sensations are some sort of material phenomena without explaining how they fit into physical theory and how they might interact with biological neurons. The strongest argument against this class of hypotheses is that no such integrating function has been found between hemispheres in split brain patients.
The best suggestion of this class was put forth by Kristof Koch who suggested that conscious experiences exist because they are required by the brain to access sensory and emotional information in all parts of the brain simultaneously and do so for a longer period of time than transient neural signalling seems to allow:"To handle this information efficiently the brain has to symbolize it. This in a nutshell is the purpose of qualia. Qualia symbolize of tacit and unarticulated data that must be present for a sufficient amount of time. Qalia, the elements of conscious experience, enable the brain to effortlessly manipulate this simultaneous information" (Koch 2004, page 242)