Hi adosa,
adosa wrote:Can eye-consciousness arise at the same time as say nose-consciousness or is it one at a time?
adosa
In my experience the higher the vipassana level and the temporal resolution the more I actually become aware of the simultaneousness of mind processes. The spot light of attention (manashikhara if I understand acinteyyo correctly) can either widen it's range or even split into several "beams". The mind seems even to work on several time-scales at once. I recall an incident involving a car and a bike crashing. I saw the external world in slow-motion (like in some movie), my physical body felt like moving through water even slower than the slow-motion of the physical sight. In addition to the physical sight was a 360 degree sight all around me at the level of my eyes (dunno what to make of this, yet, at the time it happened it felt like "well, while I am at it I can check this, too"). Then there was the mind working on a solution to keep the physical body (and, oddly, the personality) alive - it succeeded nicely, when it was over and I was absorbed in the personality again the bike was a wreck but I - having jumped down from it like some stuntman (and believe me, I am NOT a stuntman) - was standing next to it without even a scratch. The whole incident lasted maybe a second, the time from my initial realisation that there was no way to keep me from crashing into that car to me standing next to both bike and car, calm as you please.
I don't recall anything from the nose-sense during that time but eye and tactile sense worked on different time scales and mind much faster than either. And simultaneously. Naturally, after that accident I became more interested in the workings of the mind. Scientifically, it seems that the nervous system can work on different time scales. The optimisation of the Myelin sheath plays an important role in the speed of impulse propagation (
http://en.wikipedia.org/wiki/Myelin" onclick="window.open(this.href);return false; ), also the brain seems to slow itself down to the sense impulses naturally - small mammals like mice see the world in slow motion all the time, thus their fast reactions.
I don't know why the mind tends to slow itself down if not absolutely necessary, maybe more energy is required for the high temporal resolution. In any case the high temporal discernment is possible and at least on that time-scale there was multi-tasking: no switching between different mind states or from one sense to the next but all simultaneously. I believe this is as fast as my discernment ever went during some kind of verification - I mean during sittings it is difficult to know the elapsed time with some kind of precision.
I think there are (at least) three possibilities why my experience does not agree with the Abhidhammic rule of "one citta at a time": Abhidhamma is wrong, the temporal resolution was not high enough yet, or there is some misinterpretation regarding Abhidhamma scripture. As I am not yet able to repeat this kind of experience to make a thorough investigation I guess I just leave the answer open for now.