"The Quest for Consciousness - A Neurobiological Approach" by Christof Koch

This book on consciousness is by one of our leading computational neuroscientists yet it is limited by the author adopting the overly broad definition of consciousness from philosopher John Searle:

 "Consciousness consists of those states or sentience, or feeling, or awareness, which begin in the morning when we awake from a dreamless sleep and continue throughout the day until we fall into a coma or die or fall asleep again or otherwise become unconscious" (page 11).

This defines consciousness as the absence of unconsciousness. The result is that the definition does not distill out what may be the core or root of consciousness which is our conscious sensations (also known as Qalia).  Qalia is that something that allows us to see "red" when all it is in our brains is a pattern of action potentials on some neurons. All other components of consciousness are probably the effects of the brain's information processing on qalia producing neurons (and their proteins).

Another limitation is this book's hypothysis that consciousness so defined is an emergent property. Somehow complex networks such as the brain cause consciousness to emerge. The analogy the author uses is the old idea of vitalism Many at the beginning of the 1900's could not see how chemistry alone could store all the information needed to define complex biological structures so these people believed some sort of new undiscovered vitalistic force was needed. That turned out not to be the case, therefore another complexity, this time consciousness, must be similar. Yet consciousness is not information which is a measurement of state quantity.

Yet the author goes on to say "Although consciousness is fully compatable with the laws of physics, it is not feasible to predict or understand consciousness from these." (page 11) which is a contradiction of emergence. All emergent properites such as pressure leave a trail back to more fundamental levels of physics, in this case the statistical mechanics of air molecules. All emergent properties are still affected by matter and energy (physics). Physics does not affect conscousness directly, only by affecting the biochemistry of neurons can consciousness be affected by physics.

So why is the author against the other major theory for consciousness suggesting that it is a property of some higher dimensional space? He says this:

"While logically consistent, strong dualist positions are dissatisfying from a scientific viewpoint. Particularly troublesome is the mode of interaction between soul and brain. How and where is this supposed to take place? Presumably, this interaction would have to be compatable with the laws of physics. This however, would require an exchange of energy that needs to be accounted for. And what happens to this spooky substance, the soul, once its carrier, the brain, dies? Does it float around in some hyperspace, like a ghost?"

To answer his main concern. First matter (mass/energy) is not transmitted out of our universal space. From the equations of General Relativity matter defines space. If matter goes to zero so does space. The same principle holds in quantum mechanics, if matter goes to zero so does the quantum amplitude which is responsible for defining the paths of matter. In short our space is a confinement field for matter. Yet significantly,  material properties exist in physics that are not the matter of the equations, terms like electrical charge and so on. Nothing prevents charge from flowing in a closed loop to some hbigher dimensional space as long as the total quantity in our universe stays the same. By changing the flow rate or the vibration of this flow, information can flow across the spatial barrier. Therefore certain folding neural proteins could affect this flow. If everything else is impossble, the remaining alternative, no matter how unlikely it seems, is the answer.

Because of the author's broad definition of consciousness the rest of the book is about the brain function which is always fascinating. He does point out that the conscious sensations of color are most likely localized in the 4th stage (V4) of visual feature definition in a region called the fusiform gyrus (page 138). This localization of conscious sensation production is another piece of evidence against the emergent model. If emergence depends on complexity of the whole brain how does one type of conscious sensation become localized to one part of the brain? Sensory conscious sensations can be more than color. The sensation that an object is moving is also a conscious sensation and this is located in medial temporal area (page 139). If this area is damaged in a stroke, the person's vision consists of a sequence of widely separated images similar to a scenes in a strobe light. This also shows that perception is not a passive process but is instead an active process in which the brain fills in the gaps from internally generated signals. This would explain why all brain regions are reciprocally connected.

So why do we have conscious sensations or more broadly consciousness? At least the author and I agree that conscious sensations have a evolutionary purpose. He says this:

"I am not claiming that such an Uber zombie could not exist or could not be built by artificial means. I don't know about that. What I am claiming is that natural selection favored brains that make use of a dual strategy" (page 237)

Zombies are human-like unconscious robots. The author proposes the evolutionary reason for conscious sensations (qalia) is:

"To handle this information efficiently the brain has to symbolize it.This in a nutshell is the purpose of qalia. Qalia 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" (page 242)

This statement ignores the general strategy of the brain's information processing which is intersecting context control all done in a highly parallel fashion. The thalamus is the main brain region effecting this strategy. Nothing additional is needed. If the authors statement is true then how does non-energetic qalia affect energy demanding neurons in other parts of the brain? (his main arguement against higher dimensional spaces). I would propose that the most likely answer for the evolutionary purpose of qalia is not in aiding the brain's information processing but in aiding in a very general and loosely coupled way group coordination via methods not yet accounted for by physics (such as charge transfere). This group coordination would involve emotional and perceptual biasing broadcast out to the tribal group. In the end though the final way to put this arguement to rest is to to simulate brains with electronic computers to the greatest degree possible.

That conscious sensations do not produce the strongly connected communication needed to aid in the brain's information processing is shown by experiements in split brain patients. By cutting the corpus collosum in siezure prone patients to reduce the severity of those seizure scientists can study this effect.

A very rare patient in which both brain hemispheres have a language ability shows this very clearly in a report form neurologist Victor Mark (90% of people only have language ability in the left hemisphere meaning the right hemisphere can't talk or understand language).

"One half of the brain quite literally does not know what the other half does, which can lead to situations somewhere between tragedy and farce. .. When asked how many seizures she had recently experienced, her right hand held up two fingers. Her left hand then reached over and forced the fingers on her right hand down. After trying several times to talley her seizures, she paused and the simultaneously displayed three fingers with her right hand and one with her left. When Mark pointed out this descrepancy, the patient commented that her left hand frequently did things on its own. A fight ensued between the two hands that looked like some sort of slapstick routine. Only when the patient grew so frustrated that she burst into tears was one reminded of the sad nature of her situations" (page 291)

With both brain hemispheres able to speak "this led to frequent back-and-forth between them, as when Mark echoed one of her statements that she did not have feelings in her left hand. She then insisted that her hand was not numb, followed by a torrent of alternating Yes's and No's, ending with a despairing "I don't know". (page 291)

(Edit: This paragraph added March 31, 2007) The alternative to the proposal that conscious sensations evolved in us  is the idea that conscious sensations are simply a side effect of biology, an epiphenomenon, like the noise of a heart beat. This idea seems to have been first proposed in an 1884 speech by Thomas Huxley, the famous defender of Darwin (page 238 of Koch's book). Yet all epiphenomena are by products of entropy, the emergent property of statistical mechanics that all physical processes involving a transformation of energy are not perfectly efficient. Epiphenomena represent these energy leakages but since conscious sensations have nothing to do with energy this idea has no merit. If one argues that conscious sensations represent some other sort of leakage then one must explain what the neurons that produce conscious sensations are doing differently from neurons that do not produce conscious sensations.

While I disagree with the author's interpretation of conscious sensations this is the best book about consciousness that I have come across because of the sheer volume of hard neurological data. Even with that the author does not investigate the emotional, feeling level of conscious sensations.