The title “Scientific Approaches to Mysticism” reveals half the task and belies the other half—namely, which of the sciences and whose mysticism are to be considered. Is it Capra’s tao of physics, Bohm’s holomovement of undivided wholeness, or Saver/Rabin’s limbic correlates of mystical ecstasy? Is it Freud’s psychoanalytic oneness of nursing at the breast, or Goodall’s evolutionary biology of mystical wonder? Numerous mystics have presented us with a cornucopia of mystical experiences, and many sciences have been employed to analyze mysticism. Any effort to create a singular scientific approach to an “imagined singular mysticism” is doomed to vagueness. Specifics matter, and they matter in the scientific approaches to mysticism. A scientific study of mysticism must first clarify what mysticism means—namely, a conscious experience in which one feels that the normal subject-object boundaries manifest in waking consciousness are altered, presenting a state of unity, union, or interrelationship. This definition of mysticism is broad enough to encompass nature mysticism, theistic I–Thou mysticism, and various forms of non-dualistic mysticisms ranging from experiences of the oneness of Being to the awareness of the emptiness of becoming. Each of these broad categories of mysticism must be refined by examining the particular tradition in which it manifests. As such, the scientific study of mysticism cannot assume, for example, that all Christian mystics, proclaiming the ultimacy of a personal communion with the Trinitarian god, are uttering the same thing, nor that non-dualistic mystics from different traditions, such as Christianity and Hinduism, are saying different things. The scientific study of mysticism must immediately confront the threat of reductionism, in which “mystical experience” is reduced to some elemental explanation such as, “it is only one’s brain.” This threat of scientific reductionism has long been elicited by the knowledge, for example, that the intake of drugs is correlated with mystical experience; more recently, this threat of reductionism has been intensified by the knowledge that we have machines that measure the neural patterns associated with individuals having mystical experiences, and we have machines that can allegedly induce mystical experiences. Stepping beyond the psychological, cognitive, and neuropsychological approaches to mysticism, the connections between mystical experience and physics have also been drawn. Relativity and quantum theories have become the hermeneutical tools to analyze and interpret the declarations of all sorts of mystical experiences. These studies of mysticism tend to present parallel explanations of the world. Evolutionary theory and biology also offer different angles of approach to the study of mysticism proposing explanations, for example, which relate mystical experience to the evolutionary chain of being or to techniques for transcending present limitations.