Within the Catholic contemplative orders, the Carmelites have developed a special interest in mystical experiences. Beauregard and Paquette monitored fifteen Carmelite nuns with functional magnetic resonance imaging during three conditions: “mystical,” “control,” and “baseline.” It is important to note that in this study the “mystical” condition was based on retrieved memory. The nuns were asked to remember and to relive with their eyes closed the most intense mystical experience they had ever undergone during their membership in the Carmelite order. Why did the researches adopt this strategy? Because the nuns had made it clear to them before the study began that “God can’t be summoned at will.”

From James Austin’s Selfless Insight: Zen and the Meditative Transformations of Consciousness, Cambridge, Massachusetts: The MIT Press, 2009, p. 44.