@fdesilva,
Hi fdesilva,
Your interpretation of the Libet timing experiment is interesting, but seems a bit exotic. I've read some other explanations that seem more intuitive. According to one interpretation, IIRC, the subject responds to the experimenter's instructions by programming his or her brain to select an arbitrary, random moment within the next few seconds and at that point carry out the motor response (press button) and a cognitive response. I.e., move the hand, and remember where a rotating light is located when that motor "decision" seemed apparent.
We know that much of our motor behavior is carried out "on autopilot" (e.g. riding a bicycle while listening to an iPod, or walking while carrying out a conversation). So it would not be all that surprising if the motor response was started by the autopilot mechanism, and the cognitive brain found out a few fractions of a second later. We also know that the mind does a lot of creative reality interpretation, possibly including the taking of credit for a decision made "on autopilot". The true decision-making moment of the higher cortex (consciousness) could well be the starting of that autopilot mechanism. IIRC, there were later timing experiments that showed that conscious decisions to stop previously initiated motor actions did occur in the cortex just prior to the stopping of the action. I've seen this called the proof of "free won't".
However, your point about the potential relativity violation of the conscious awareness of more than one thing at the same instant (e.g., that the car is blue and the girl driving the car is pretty -- hey, it's summer here in NJ) is VERY interesting. Here's how I would analyze it. Let's assume that the brain is a computational device tied to multiple sensory scanning devices sending a multitude of signals about the environment surrounding the body. That device has to make decisions on survival behavior in response to the whole of those scanner signals (from the many ear nerves, eye nerves, olfactory nerves, etc.). The computer has been wired and programmed to consider all of the input signals on a continual basis, and make continual behavior responses and adjustments based on these signals.
Any computer has to make these decisions in a bumpy manner; e.g., new decisions every fraction of a second. The decision making cannot be perfectly continuous. That is not physically possible. Even with for the fastest sensing and computing device, the quantum limits on elementary particle size and speed means that information comes in by bits, not in a steady flow. (The original point of quantum physics is that there is nothing perfectly continuous in the physical world, there are limits to smallness and divisibility). The time bit for the receipt of an electron would be extremely small, but not infinitely small. In reality, the neurons work by slower molecular electrochemical processes, processes that occur bit-by-bit, not continuously. Those bits are much longer than the shortest possible quantum time interval.
(Perhaps they all act at once, in synch, every so many micro-seconds. Or perhaps they blink in offset phases, so at every instant at least some are blinking and some are dark. But if that is the case, some parts of our consciousness should be dark at every instant, those dark parts moving around based on the timing of the sense inputs and processing delays.)
So, putting aside the question of how consciousness emerges from this process of signal input / data processing / decision making, it is fairly clear that the brain is operating in "ticks" (like the tick of a watch's second hand), not on a smooth, continuous basis. So, one would expect consciousness, if fully determined by these physical processes, to occur bit - by - bit through time (or alternately on a spotty-field basis). I believe that some mind analysts do interpret consciousness on that basis. For example, I think that Galen Strawson compares consciousness (and "the self") to a string of pearls, each pearl representing a moment of conscious response to the brains tick-tick-tick processing of sensory input data. Perhaps something like Hume's bundle and parade metaphors for the conscious self.
So why do we subjectively experience a continuous experience of being, and not the flick-flick-flick like a slowed down movie? You could say that it's just like a movie, or a TV screen; speed the flicks up enough and humans perceive it continuously, smoothly. OK, but that just begs the question. The brain certainly is processing input data that flicks. What is the fundamental difference between flicking every quarter second versus every millionth of a second? Looking at it another way, why aren't we subjectively aware of the inherent pixelation of our sense data inputs? Even spread over a few billion neurons, there still is some minimum pixel size to the mind's "information picture". Why is there a threshold between data fed to us as big, artificial pixels, which we notice, and the little, natural pixels that we don't?
There is a brain malady whereby the "phi" fails to happen, the flicking never goes away (i.e., motion blindness, damage to the V5 area). Everything then seems like a slow motion movie. So obviously, subjective experience is driven to a great extent by the physics of the brain. Somehow those brain processes need to speed up the processing steps to reach some threshold where the "continuous illusion" occurs.
But once that threshold is reached, a state-transition takes place in our subjective experience. An emergence effect? Yes, certainly. A strong emergence effect, one that does not supervene on / reduce to the physics supporting it. So strong as to make you wonder, why? For what purpose? The non-sentient computer cares less about flickering in its decision making; that's just life in a quantum world. Why do conscious minds care? Why are they (i.e, "we") given subjective "hints of eternity", hints of smooth perfection that do not exist in a universe constructed of quantum pieces of time, space and energy?
If this is an 'illusion', just what is having and experiencing that illusion? I can accept the possibility that a highly developed connectionist machine might come up with concepts like 'perfect smoothness' that would 'overshoot' reality. But does that entirely explain a subjective experience of that overblown concept?
Hmmmmmmmm. I know there must be a huge body of discussion about this, more sophisticated than my ruminations. Interesting, nonetheless.
Jim G.
POST SCRIPT, Aug 23, 2008:
Some further thoughts on the relativity point and regarding my own 'flicker and pixelate' point. First, regarding any relativity problems with the mind forming a simultaneous image of two seperate events occuring within the body's sensory scanning range. Recall that the other major implication of the Libet experiments was that there is up to a half second delay between an environmental signal and conscious awareness of it. In that half second, there is plenty of time for the brain, as a computing device, to exchange information between information inputs from two seperate events and to form a unified "picture", if you will. That "information picture" is not for viewing by a little being in the Cartesian theater, of course, but for use in behavioral decisions and information storage for future behavioral decisions.
So, there aren't necessarily any violations of relativity's restriction of information transmission to light speed, given that half second to exchange "point data" from the senses and come up with an abstracted "bigger picture" through connectionist webs (and yes, also through chaotic attractors on the highest "macro-levels" of brain processing; tip of the hat again to Paul H for pointing out the importance of chaotic determinism).
Second, regarding "flickering" or "pixelation": I was making a bit of a mistake there in looking at consciousness in something like the Cartesian Theater mode. I've read enough to know that whatever consciousness is, it is NOT like a homunculus watching the raw sensory data coming in on a wide-screen TV with a great surround-sound and aromatherapy system. I should have realized that the brain does a lot more processing of sensory inputs than seems apparent on the "folk awareness" level.
We don't respond to a "screen of pixels"; our executive levels are being presented with an ongoing-parade of conculsions regarding "what's out there" after V1 through V100 or whatever get through with the sensory inputs. E.g., blue, box, large portion of left vision field; over that: yellow, ovals, black in center, arranged in flower pattern; under that, green, tube, like flower stem; etc. These come in voracious, continual detail, including details about relative trajectories, relative movements, relative changes, etc. The connectionist devices feed the executive decision-maker and memory-maker the themes, not the raw (or slightly smoothed-out) data. Those themes are smoothed out to a large degree; that's just what parallel connectionist devices do. So, we are "aware" of the conclusion that a ball is moving through the air at some rate relative to other things in the awareness frame, and not of a flickering, pixelated image of that ball (as with the hypothetical homunculus in the Cartesian Theater). When something changes in the major themes and trends, e.g. brown rabbit now moving southwest instead of northeast, relative speed of rabbit slow but accellerating, then the "awareness" changes.
But -- despite all this neuroscientific enlightenment, I myself get the sense that some "qualia mystery" remains. Even if there isn't a relativity problem, even if there isn't a pixel-awareness problem, even if there isn't a temporal flickering problem to conscious perception, due to the amazing things that a connectionist data processing system can do, there still is a big question: just what then takes all of these smoothed-out themes and trend analyses derived from the many inputs from the environmental sensors, and turns them into "vivid subjective experience" with its usual smoothness? Why do we even need such subjective experience? (And what would motion blindness be -- failure of the PDP devices to completely process and smooth-out the inputs, thus the "conclusion output" to subjective experience being closer to raw flickering data?)
Sorry, I'm still not ready to burn my membership card in the mystery dualism club, at least the epistemological mystery dualism club.
, but interesting. Thanks for the stats and theory? Ironically, ideas are not often shared on the forum. (my opinion). Only opinions.
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