After reading the post and 59 comments I have a couple remarks which might be worthwhile and do not seem to have been addressed yet.

First there is not much mention of the extensive scientific research on the topic of meditation and its possible benefits to physical and mental health. I am personally most interested in the U. Wisconsin meditation studies, such as documented here. Those studies use Tibetan Buddhist monks who perform their meditation with a technique which is not exactly vipassana, but they have the largest amount of measured data I know of. We can argue about personal experiences interminably, but data is far more convincing to me.

The best single systematic source for the known science about meditation may be compiled by Charles Tart in his book Altered States of Consciousness. Tart did his undergraduate in Electrical Engineering before turning to Psychology, and he takes pains to use as much rigorous science as he can on his esoteric research. This is very hard to do. Tart's personal practice is very close to vipassana.

I see a problem with the idea of inviting inexperienced practitioners for ten day intensive retreats. In the temple where I meditated for several years (Zen) they did retreats. Mostly they were for six days, not ten. And people with less than six months of steady participation were never invited. One time I was uninvited from a retreat because one of the senior monks was a hard ass and I had only been affiliated with the temple for eighteen months. This temple definitely practiced a crawl and then walk teaching protocol.

There are two fallacies involved here for those with a specific interest in cognitive bias. One is a sunk cost fallacy. If you have sunk ten days into it you are less willing to ditch it because fallible humans are often unable to act like good economists and recognize that sunk costs are irrelevant. The second fallacy is the idea that big risks are necessary to reap big rewards. This was most effectively debunked by the psychologist Irwin Yalom and his analysis of large group trainings (such as Erhard Seminar Training) back in the 1970's. He was looking at group psychotherapy, not meditation retreats; in the Human Potential Movement there is often a large overlap between these two activities. There is a famous anecdote of the Zen master who, when his student reported seeing some magnificent vision in his meditation, instructed the student to meditate on and such bothersome distractions will pass.

Inexperienced meditators are notorious for thinking they have achieved a great insight which makes little more sense than that stuff you write down that sounds so great when you are really stoned, and the next day is not much more than jabberwocky.

This is not intended to discourage the curious. Meditation is great stuff. Multi-tasking is the bane of many of my friends and colleagues; almost all of them would improve their mental health greatly by taking some time to empty their mind of as much garbage as possible for a few minutes daily. This big production of a ten day retreat for beginners is not generally considered a good idea amongst the monks who I talk to.