http://www.quantumconsciousness.org/presentations/whatisconsciousness.html
The Problem of Consciousness
Conventional explanations portray consciousness as an emergent
property of classical computer-like activities in the brain's neural
networks. The prevailing views among scientists in this camp are that
1) patterns of neural network activities correlate with mental states,
2) synchronous network oscillations in thalamus and cerebral cortex
temporally bind information, and 3) consciousness emerges as a novel
property of computational complexity among neurons.
However, these approaches appear to fall short in fully explaining
certain enigmatic features of consciousness, such as:
* The nature of subjective experience, or 'qualia'- our 'inner
life' (Chalmers' "hard problem");
* Binding of spatially distributed brain activities into unitary
objects in vision, and a coherent sense of self, or 'oneness';
* Transition from pre-conscious processes to consciousness itself;
* Non-computability, or the notion that consciousness involves a
factor which is neither random, nor algorithmic, and that
consciousness cannot be simulated (Penrose, 1989, 1994, 1997);
* Free will; and,
* Subjective time flow.
Brain imaging technologies demonstrate anatomical location of
activities which appear to correlate with consciousness, but which may
not be directly responsible for consciousness.
Figure 1. PET scan image of brain showing visual and auditory
recognition (from S Petersen, Neuroimaging Laboratory, Washington
University, St. Louis. Also see J.A. Hobson "Consciousness,"
Scientific American Library, 1999, p. 65).
Figure 2. Electrophysiological correlates of consciousness.
How do neural firings lead to thoughts and feelings? The conventional
(a.k.a. functionalist, reductionist, materialist, physicalist,
computationalist) approach argues that neurons and their chemical
synapses are the fundamental units of information in the brain, and
that conscious experience emerges when a critical level of complexity
is reached in the brain's neural networks.
The basic idea is that the mind is a computer functioning in the brain
(brain = mind = computer). However in fitting the brain to a
computational view, such explanations omit incompatible
neurophysiological details:
* Widespread apparent randomness at all levels of neural processes
(is it really noise, or underlying levels of complexity?);
* Glial cells (which account for some 80% of brain);
* Dendritic-dendritic processing;
* Electrotonic gap junctions;
* Cytoplasmic/cytoskeletal activities; and,
* Living state (the brain is alive!)
A further difficulty is the absence of testable hypotheses in
emergence theory. No threshold or rationale is specified; rather,
consciousness "just happens".
Finally, the complexity of individual neurons and synapses is not
accounted for in such arguments. Since many forms of motile
single-celled organisms lacking neurons or synapses are able to swim,
find food, learn, and multiply through the use of their internal
cytoskeleton, can they be considered more advanced than neurons?
more...
