For what it's worth.... I spent quite a bit of time in zazen in my late teens/early twenties. None of this koan nonsense, or irrationalities, just following my breath, and eventually, just sitting. No big deal, nothing to write home about. Anyway, one day I had a motorcyle accident. Could have been a big deal, but other than ending up on crutches for awhile I walked away from it. I was mostly (pychologically) numb for a few hours following it - the trip to the hospital, xrays, all that.
Coming home - BAM! Everything dropped away and I started giggling nonstop. I could go on and on in words but what's the point? I don't say that in any mystical way, but how do you describe love in words, or any feeling/emotion/brain state? Can't really be done. Anyway, so far as I can tell this was what they call a "tip of the tongue" experience - I was still thinking "hey, this is new" - ie I was still observing it happening.
I totally agree that this must be a brain state; after all, we are meat. It was fun, I spent a few weeks just totally engaged in the moment, but over time it faded away. It's really not something I feel I want to chase, or get again. I view it as a different brain state, not a 'better' one, or closer to "truth" or reality, or anything like that. I can see how this sort of thing could be very useful for someone who spends their lives mulling about what could have been, "I can't believe so-and-so said that", all that negative energy. On the other hand, I get a heck of a lot of milage BY mulling over things. For me, it's part of the creative and intellectual process.
I'm not poo-pooing it, as I draw on it all the time. Heck, this morning I started to get irritated because the person in front of me was driving too slow to catch the next light in time, and then I laughed at myself, realized what I was doing, and just sat back and enjoyed my drive.
Zen? Not zen? I don't know, I don't care. What I experienced felt exactly like what all the descriptions of those brain states sound like, and it wasn't too much like I had imagined it was like beforehand. Like Kevin, I think the same brain state is experienced in many cultures. I suspect those that have near death experiences may be shocked into it.
Interestingly, my girlfriend is a neuroscientist, and her institute is involved in this research. They will be studying this phenomen using MRI and other techniques, and will be testing, among others, the Dalai Lama. Stay tuned...