Although I ultimately would join with the chorus ITT that's opposing the naive empiricist account of consciousness, as people (presumably) interested in scientific knowledge, it's worth reflecting on what makes this position attractive. Dennett and his ilk offer a fairly convincing account of the mechanisms that underlie the operations of perception by simply borrowing their description from natural science. They're going with "whatever is the current best scientific understanding of the operations of the brain and sensory organs." Although this view leaves plenty of room for doubt around the margins, especially where there are competing scientific theories, and possibly also opens up a Kuhnian attack (there could always be another paradigm shift!), Dennett & co. can just respond that their opponents are no better off, being themselves historically located subjects with limited scientific knowledge.
Their point (and maybe also Masque de Z's, I didn't read all of his posts) is that the flow of experiences inside our heads, "qualia," is directly determined by--is a function of--the specific arrangement of neurons and glial cells and neurotransmitters inside our brains, extended through the nervous system toward contact with the "outside" world, i.e., photons, sound waves, chemical signals, electrical charges, and all the other things to which our senses respond
+ some mechanism that allows the brain to carry out computation. In a certain sense, this is obviously correct, since we seem to experience a world about which we can make rational conclusions. But where Dennett & co. err is in assuming that this means that the flow of experience--we're calling it consciousness--in some way
reduces to or
is an emergent phenomenon of this physical arrangement.
Penrose & Hameroff show that, even within a fully empiricist paradigm, this need not be the case. Dennett's position, they argue, fails to understand the significance of the quantum revolution. If this is the nature of consciousness, they argue, the state of a conscious system can never be computed. If at any point the physical process generating it depends on (is a function of) a superposition--i.e., if anything in the brain doesn't behave as a classical computer--then we can't get there; the quantum nature of the universe imposes a hard limit. Even with perfect information (a completed
connectomics project, say), the computational engine attempting to provide a complete description of the state of the brain-machine will hit a limit imposed by quantum indeterminacy. Moreover, the making of the measurement necessary to completely determine the state of the system would cause the wave function to collapse, such that, from an outside perspective, the operations of consciousness will always appear completely determinate.
Penrose shows that such non-computable functions--non-repeating patterns--are perfectly possible in mathematics (Google "Penrose tiles"); Hameroff provides a candidate structure within the brain that's potentially sensitive to quantum-scale vibration: microtubules, which are located in the neuronal cytoskeleton. For me, their theory is deeply appealing in that it seems to explain free will (no one can know
exactly what I'll do before I do it, not even me); the "problem" of other minds (behavior that is actually the result of a non-computable process appears deterministic from outside); and the semi-regularities of human psychology (non-computable processes still exhibit local patterns and predictable properties depending on their parameters).
I'd put some YouTube clips in here but you guys know how to use the search bar, I presume.
Last edited by DrModern; 07-14-2018 at 09:34 AM.