Part of his book is about mystical experiences. Based on James’s study of accounts of such experiences, he concluded that their two primary features are “illumination” and “union.” Illumination has a twofold meaning. The experiences often involve light, luminosity, radiance. Moreover, they involve “enlightenment,” a new way of seeing. “Union” (or “communion”) refers to the experience of connectedness and the disappearance or softening of the distinction between self and world.
