Zazen as an Altered State (can't share meditative experience)
When I began to practice zazen in my early 30’s, I knew some other beginners who, in contrast to myself, were trying to share their enthusiasm for the practice with their families. By and large, they found their families unreceptive. The reason for that is that the state of mind of a person doing zazen is an altered state of consciousness. An altered state is simply a waking state that differs from day-to-day ordinary waking consciousness.

The term, “altered state of consciousness” or just “altered state” was possibly coined by a certain Charles Tart. At least Mr. Tart gave currency to the term in the 70’s partly through articles in The Journal of Transpersonal Psychology. I remember reading some of these articles and picking up the point that experience in an altered state could not be understood by a person not in that state. This made for a considerable divide between people who had had a mystical experience and the general public.
After sitting for a while in zazen, practitioners often experience a state of mind in which they feel unified with their breathing and other sensations, and in which, on the edge of consciousness, they may sense that everything is right with a unified world in which they are a comfortable part. Whether this state of mind can be called “mystical” or not, it is certainly an altered state, not an ordinary one.
Given that it is an altered state, the state of mind of a zazen practitioner cannot be shared with someone who is not also a practitioner. In the life of a beginning meditator, this may result in a feeling of loneliness. This feeling dissipates with the growth of a sense of self-sufficiency in the practice.