Causative factor for altered states

Whether an altered mode of awareness or mystic experience is achieved by deliberate practice of a technique or whether it occurs spontaneously, there seems invariably to be a sudden occurrence which triggers the change taking place or a set of circumstances which activate the mechanism for sudden illumination. Often this may be music, or beautiful or awe-inspiring surroundings. Other factors have been variously described: childbirth; grief; illness; nearness of death; sensual experience; flight; sports; achievement, and so on.