Consciousness

[Alan V]

As always, people using key words in different senses. There's consciousness in the functional sense (where it's basically information processing) and there's consciousness in the phenomenological sense (which is what I believe the OP is centered on).

From Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts by Stanislas Dehaene.

There are different aspects of consciousness:
* The subcortical conscious state (sleep, dreaming, waking).
* Cortical/thalamic vigilance.
* Attention, which is focusing on specific information. “Attention’s sieve operates largely unconsciously – attention is dissociable from conscious access.”
* Phenomenal awareness, which equals qualia.
* Conscious access, which is the information which enters awareness (genuine consciousness). “At any given time, a massive flow of sensory stimulation reaches our senses, but our conscious mind seems to gain access to only a very small amount of it.” While its potential repertoire is vast, at any given moment its actual repertoire is dramatically limited. It must withdraw from one item in order to gain access to another. Subcortical wakefulness, cortical/thalamic vigilance, and attention “are just enabling conditions for conscious access.” Scientists can study conscious access through a variety of methods, which the book details.

So yes, consciousness is complicated. Both unconscious and conscious brain functions process information. Consciousness in a phenomenal sense, or "fame in the brain" as Dennett called it, enables a certain variety of processing, but it can also be used for aesthetic appreciation as well. However, I doubt it evolved for the latter.

Also from the same book:

Supporting observations:
The functions of consciousness are reflected in brain architecture, in the length of neurons, the numbers of their dendrites/spines, and their extensive connections to other areas. There are 15,000 spines or more on each human prefrontal neuron. “We believe that a special set of neurons diffuses conscious messages throughout the brain: giant cells whose long axons crisscross the cortex, interconnecting it into an integrated whole.” “Neurons with long-distance axons are most abundant in the prefrontal cortex.” “When enough brain regions agree about the importance of incoming sensory information, they synchronize into a large-scale state of global communication. A broad network ignites into a burst of high-level activation – and the nature of this ignition explains our empirical signatures of consciousness.” “Anatomically, bottom-up and top-down pathways are both present throughout the cortex. Most long-distance connections are bi-directional, and the descending top-down projections often vastly outnumber the ascending ones.” “During the consciously perceived trials, we observed a massive increase in bidirectional causality throughout the brain.”

“Not all brain circuits are equally important for conscious experience. Peripheral sensory and motor circuits can be activated without necessarily generating a conscious experience. Higher-order regions of the temporal, parietal, and prefrontal cortexes, on the other hand, are more intimately associated with a reportable conscious experience, since their stimulation can induce purely subjective hallucinations that have no foundation in objective reality.”