It's my understanding that the brain's processing of sensory information is discrete in the sense that if two sensory impulses arrive close enough to each other (about 20 msec), they're perceived as simultaenous. Yet our experience appears to us as continuous. My guess would be that meditation involves opening conscious access to earlier processing stages in the brain, where our sensory experience still seems somewhat discrete - thus the "vibrations". This would seem compatible with e.g. this paper, which hypothesizes that meditation reduces the amount of end-stage processing in the prefrontal cortex, as well as various reports from meditation practicioners which also seem to involve access to earlier processing stages of sensory data (e.g. being able to separately perceive a raw sensory input and the resulting emotional reaction to it). It would also explain why learning to see the vibrations would lead to an ability to see the concept of self - or the "label of the observer", as the grandparent calls it - as something arbitrary, if the same process also allowed us to see part of the normally pre-conscious processing stages that constructed the sensation of a coherent, unchanging self. Though it should be noted that this process of deconstruction seems potentially hazardous for one's mental health: once you start seeing just how arbitrary your self and world-image is, it can be quite frightening and disorienting. Suddenly some of the concepts which your brain has used to order and understand reality with just stop working: [...] Likewise, if the process involves greater access to unprocessed raw data (including raw emotions) and a reduction in the activity of the prefrontal cortex which usually regulates and mediates those emotions, that's going to cause a lot of trouble as well. I suspect that these are the causes of the so-called "Dark Night", a stage in meditation which may cause serious depression and clinical impairment until it's overcome (via more medita

Although I have no experience with any extensive program of meditation, it is clear to me that "vibrations" is a word given to a certain aspect of internal experience that is "subtle" in the sense that a person would probably not notice it without spending quite a few hours in mediation or at least in paying close attention internal experience. ADDED. Because any two human minds have so much in common, it is possible to have a worthwhile discussion about various aspects of internal experience. Although it's a lot harder to catch someone in a lie about their internal experience than it is to catch them in a lie about external reality, that does not prevent worthwhile sharing of knowledge about internal experiences. ADDED. Great writing, BTW, PyryP (author of grandparent).